Journal articles on the topic 'Stratigraphic Miocene'
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1
Munsterman, D. K., and H. Brinkhuis. "A southern North Sea Miocene dinoflagellate cyst zonation." Netherlands Journal of Geosciences - Geologie en Mijnbouw 83, no. 4 (December 2004): 267–85. http://dx.doi.org/10.1017/s0016774600020369.
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AbstractAn integrated stratigraphical analysis emphasizing organic-walled dinoflagellate cyst (dinocyst) distribution has been carried out on multiple boreholes penetrating the Miocene in the subsurface of the Netherlands (southern North Sea Basin). The bulk of the investigated successions is attributed to the Breda Formation, a regional lithostatigraphical unit most complete in the south-eastern part of the Netherlands. In concert with a first regional integrated bio (chrono) sequence-stratigraphical framework, fourteen informal dinocyst zones for the southern North Sea Miocene (SNSM), and three subzones are proposed for the Breda Formation. By also integrating (chrono)stratigraphic information from Mediterranean and North Atlantic dinocyst studies a first ever detailed age-model is here proposed for the Miocene in the subsurface of the Netherlands.
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Mai, Hoàng Đảm, and Thị Thắm Nguyễn. "Biostratigraphic characteristics and correction of the boundary between Miocene and Oligocene sediments in the northern Malay - Tho Chu basin." Petrovietnam Journal 5 (July 4, 2022): 19–27. http://dx.doi.org/10.47800/pvj.2022.05-03.
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Stratigraphic study in oil and gas wells is dependent on the research method and the characteristics of the collected samples, such as sample types and spaces between samples, that is why the stratigraphic boundary of the wells may fluctuate in a certain sedimentary range. Therefore, when re-evaluating the hydrocarbon potential or expanding the petroleum exploration targets of an area, we need to study additional evidence and geological events to correct the stratigraphic boundary of the well and correlate regional stratigraphy. These studies often use biostratigraphic and seismic stratigraphic methods.
This paper provides evidence on biostratigraphy to correct the stratigraphic boundary between Miocene and Oligocene sediments in the northern Malay - Tho Chu basin and compares them with the general stratigraphy of the Malay basin. The research results determined that the top of the Oligocene sediment after correcting is higher than what was specified in the previous studies based on marker fossil findings in a palynomorph abundance cycle; and there are similar biostratigraphic characteristics between the studied area and the Malay basin.
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Pashko, Pandeli, and Shyqyri Aliaj. "Stratigraphy and tectonic evolution of Late Miocene - Quaternary Basins in Eastern Albania: A Review." Bulletin of the Geological Society of Greece 56, no. 1 (December 28, 2020): 317. http://dx.doi.org/10.12681/bgsg.22064.
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The new stratigraphic data and tectonic evolution of the Late Miocene-Quaternary basins developed in Eastern Albania are presented. The reviewed stratigraphic data for deposits filling the Ohrid, Prespa and Devolli basins show that they began to form in Late Miocene. The stratigraphic evidences from eastern Albania are confronted with the stratigraphic data from the lake basins in western North Macedonia and northwestern Greece that all show the same age of infilling. The Cenozoic tectonic evolution of Eastern Albania consists of two phases of extensional deformations, the first in Middle Eocene-Late Miocene (Pannonian/Tortonian) and the second starting in Late Miocene (Pontian s. l.). The two phases are separated by a short compressive phase at the Late Miocene (end of Pannonian/Tortonian) or pre-Pontian s. l. time. In Late Miocene (Pontian) began forming the system of the Ohrid, Prespa and Devolli basins developed along the Drini fault zone. The Korça, Kolonja, Kukesi and Tropoja basins began to form since Pliocene and the Peshkopi Basin since Early Pleistocene. Finally, only the Ohrid and Prespa lakes are still active. The Late Miocene-Pleistocene basins were filled by lacustrine, lacustrine-fluvial and terrestrial sediments of the great thickness and of varied lithology: conglomerates, gravels, sandstones, sands, claystone and marls with lignite seams. Molluscs, microflora and flora, ostracods and vertebrates are found. The Lake Ohrid is a tectonically active graben formed during two main phases of deformation: (1) a trans-tensional phase which generated a pull-apart basin, and (2) an extensional phase which leads to its present geometry. All basins in Eastern Albania are situated in a basin and range-like (graben and horst) geodynamical setting. The inferred stratigraphic and tectonic evolution of Late Miocene-Quaternary basins in Eastern Albania as well as the relief formation and thermochronological data show that the Late Miocene-Quaternary period which led to the recent geological structure of Albania and its rapid relief formation, can be accepted as ‘Neotectonic period’.
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Pashko, Pandeli, and Shyqyri Aliaj. "Stratigraphy and tectonic evolution of Late Miocene - Quaternary Basins in Eastern Albania: A Review." Bulletin of the Geological Society of Greece 56, no. 1 (December 28, 2020): 317. http://dx.doi.org/10.12681/bgsg.22064.
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The new stratigraphic data and tectonic evolution of the Late Miocene-Quaternary basins developed in Eastern Albania are presented. The reviewed stratigraphic data for deposits filling the Ohrid, Prespa and Devolli basins show that they began to form in Late Miocene. The stratigraphic evidences from eastern Albania are confronted with the stratigraphic data from the lake basins in western North Macedonia and northwestern Greece that all show the same age of infilling. The Cenozoic tectonic evolution of Eastern Albania consists of two phases of extensional deformations, the first in Middle Eocene-Late Miocene (Pannonian/Tortonian) and the second starting in Late Miocene (Pontian s. l.). The two phases are separated by a short compressive phase at the Late Miocene (end of Pannonian/Tortonian) or pre-Pontian s. l. time. In Late Miocene (Pontian) began forming the system of the Ohrid, Prespa and Devolli basins developed along the Drini fault zone. The Korça, Kolonja, Kukesi and Tropoja basins began to form since Pliocene and the Peshkopi Basin since Early Pleistocene. Finally, only the Ohrid and Prespa lakes are still active. The Late Miocene-Pleistocene basins were filled by lacustrine, lacustrine-fluvial and terrestrial sediments of the great thickness and of varied lithology: conglomerates, gravels, sandstones, sands, claystone and marls with lignite seams. Molluscs, microflora and flora, ostracods and vertebrates are found. The Lake Ohrid is a tectonically active graben formed during two main phases of deformation: (1) a trans-tensional phase which generated a pull-apart basin, and (2) an extensional phase which leads to its present geometry. All basins in Eastern Albania are situated in a basin and range-like (graben and horst) geodynamical setting. The inferred stratigraphic and tectonic evolution of Late Miocene-Quaternary basins in Eastern Albania as well as the relief formation and thermochronological data show that the Late Miocene-Quaternary period which led to the recent geological structure of Albania and its rapid relief formation, can be accepted as ‘Neotectonic period’.
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Mamengko, David Victor, Yoga B.Sendjadja, Budi Mulyana, Hermes Panggabean, Iyan Haryanto, Eko Budi Lelono, Juwita Trivianty Musu, and Panuju Panuju. "Perkembangan Fasies Sedimen Formasi Mamberamo Berumur Miosen Akhir-Pliosen di Cekungan Papua Utara." Jurnal Geologi dan Sumberdaya Mineral 20, no. 1 (February 25, 2019): 37. http://dx.doi.org/10.33332/jgsm.2019.v20.1.37-47.
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North Papua Basin is a fore arc basin located in northern coastal of Papua Island. This basin filled by Middle-Upper Miocene turbidite sediment and overlied by Upper Miocene – Quarternary clastic sediment. Upper Miocene – Quaternary clastic sediments (Mamberamo Formation) composed by interbedding conglomerate, sandstone and shale as molasses deposit. A detailed stratigraphic study was performed to identify facies and its association of the Mamberamo Formation to that give a new perspective on the characteristics and development of facies succession of Lower Mamberamo Formation. Result shows that the Lower Mamberamo Formation consists of three facies: A) cross bedding sandstone (subtidal), B) heterolothic silty shale (intra-tidal), C) carbonaceous shale (supra-tidal) deposited on Late Miocen to Plio-Pleistocene during centra range orogeny (syn-orogeny) as molasses deposits.Keywords: Fore arc basin, North Papua Basin, Mamberamo Formation, molasse deposits.
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Mamengko, David Victor, Yoga B.Sendjadja, Budi Mulyana, Hermes Panggabean, Iyan Haryanto, Eko Budi Lelono, Juwita Trivianty Musu, and Panuju Panuju. "Perkembangan Fasies Sedimen Formasi Mamberamo Berumur Miosen Akhir-Pliosen di Cekungan Papua Utara." Jurnal Geologi dan Sumberdaya Mineral 20, no. 1 (February 25, 2019): 37. http://dx.doi.org/10.33332/jgsm.geologi.20.1.37-47.
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North Papua Basin is a fore arc basin located in northern coastal of Papua Island. This basin filled by Middle-Upper Miocene turbidite sediment and overlied by Upper Miocene – Quarternary clastic sediment. Upper Miocene – Quaternary clastic sediments (Mamberamo Formation) composed by interbedding conglomerate, sandstone and shale as molasses deposit. A detailed stratigraphic study was performed to identify facies and its association of the Mamberamo Formation to that give a new perspective on the characteristics and development of facies succession of Lower Mamberamo Formation. Result shows that the Lower Mamberamo Formation consists of three facies: A) cross bedding sandstone (subtidal), B) heterolothic silty shale (intra-tidal), C) carbonaceous shale (supra-tidal) deposited on Late Miocen to Plio-Pleistocene during centra range orogeny (syn-orogeny) as molasses deposits.Keywords: Fore arc basin, North Papua Basin, Mamberamo Formation, molasse deposits.
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Mamengko, David Victor, Yoga B.Sendjadja, Budi Mulyana, Hermes Panggabean, Iyan Haryanto, Eko Budi Lelono, Juwita Trivianty Musu, and Panuju Panuju. "Perkembangan Fasies Sedimen Formasi Mamberamo Berumur Miosen Akhir-Pliosen di Cekungan Papua Utara." Jurnal Geologi dan Sumberdaya Mineral 20, no. 1 (February 25, 2019): 37. http://dx.doi.org/10.33332/jgsm.geologi.v20i1.399.
Full textAbstract:
North Papua Basin is a fore arc basin located in northern coastal of Papua Island. This basin filled by Middle-Upper Miocene turbidite sediment and overlied by Upper Miocene – Quarternary clastic sediment. Upper Miocene – Quaternary clastic sediments (Mamberamo Formation) composed by interbedding conglomerate, sandstone and shale as molasses deposit. A detailed stratigraphic study was performed to identify facies and its association of the Mamberamo Formation to that give a new perspective on the characteristics and development of facies succession of Lower Mamberamo Formation. Result shows that the Lower Mamberamo Formation consists of three facies: A) cross bedding sandstone (subtidal), B) heterolothic silty shale (intra-tidal), C) carbonaceous shale (supra-tidal) deposited on Late Miocen to Plio-Pleistocene during centra range orogeny (syn-orogeny) as molasses deposits.Keywords: Fore arc basin, North Papua Basin, Mamberamo Formation, molasse deposits.
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Mamengko, David Victor, Yoga B.Sendjadja, Budi Mulyana, Hermes Panggabean, Iyan Haryanto, Eko Budi Lelono, Juwita Trivianty Musu, and Panuju Panuju. "Perkembangan Fasies Sedimen Formasi Mamberamo Berumur Miosen Akhir-Pliosen di Cekungan Papua Utara." Jurnal Geologi dan Sumberdaya Mineral 20, no. 1 (February 25, 2019): 37. http://dx.doi.org/10.33332/jgsm.v20i1.399.
Full textAbstract:
North Papua Basin is a fore arc basin located in northern coastal of Papua Island. This basin filled by Middle-Upper Miocene turbidite sediment and overlied by Upper Miocene – Quarternary clastic sediment. Upper Miocene – Quaternary clastic sediments (Mamberamo Formation) composed by interbedding conglomerate, sandstone and shale as molasses deposit. A detailed stratigraphic study was performed to identify facies and its association of the Mamberamo Formation to that give a new perspective on the characteristics and development of facies succession of Lower Mamberamo Formation. Result shows that the Lower Mamberamo Formation consists of three facies: A) cross bedding sandstone (subtidal), B) heterolothic silty shale (intra-tidal), C) carbonaceous shale (supra-tidal) deposited on Late Miocen to Plio-Pleistocene during centra range orogeny (syn-orogeny) as molasses deposits.Keywords: Fore arc basin, North Papua Basin, Mamberamo Formation, molasse deposits.
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BERGH, EUGENE W., and JOHN S. COMPTON. "Taxonomy of Middle Miocene foraminifera from the northern Namibian continental shelf." Zootaxa 5091, no. 1 (January 12, 2022): 1–55. http://dx.doi.org/10.11646/zootaxa.5091.1.1.
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Middle Miocene foraminifera from the northern Namibian outer continental shelf are indicators of a period prior to the initiation of the Benguela Upwelling System (BUS). This study provides an update to the occurrence and taxonomy of Miocene foraminifera from the continental margin of Namibia. The taxonomy of 51 benthic and 12 planktic foraminiferal species from the northern Namibian shelf are discussed, their stratigraphic significance given, and their ecological preferences and regional distribution summarised within this study. The identification of extinct planktic foraminifera provided key stratigraphic control for the middle Miocene strata of this region. The taxa identified in this study provide a distinct and different assemblage to the overlying younger strata. Many of the species recorded in this study have not been identified in the region and are reported for the first time from the middle Miocene on the southwestern continental shelf of Africa, off Namibia. A total of 47 species are identified and discussed for the first time from this region. Nineteen species recorded in this study are extinct and eleven taxa reported here have previously only been reported on the genus level on the southwestern shelf of South Africa. Seven benthic species (Amphicoryna scalaris, Marginulina obesa, Glandulina laevigata, Globocassidulina subglobosa, Uvigerina peregrina, Sphaeroidina bulloides and Melonis affinis) and two planktic species (Globigerina bulloides and Orbulina universa) did not disappear from the regional stratigraphy and continued to occur in Plio-Pleistocene to Recent sediments along the southwestern continental shelf of Africa.
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Drury, Anna Joy, Thomas Westerhold, David Hodell, and Ursula Röhl. "Reinforcing the North Atlantic backbone: revision and extension of the composite splice at ODP Site 982." Climate of the Past 14, no. 3 (March 8, 2018): 321–38. http://dx.doi.org/10.5194/cp-14-321-2018.
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Abstract. Ocean Drilling Program (ODP) Site 982 represents a key location for understanding the evolution of climate in the North Atlantic over the past 12 Ma. However, concerns exist about the validity and robustness of the underlying stratigraphy and astrochronology, which currently limits the adequacy of this site for high-resolution climate studies. To resolve this uncertainty, we verify and extend the early Pliocene to late Miocene shipboard composite splice at Site 982 using high-resolution XRF core scanning data and establish a robust high-resolution benthic foraminiferal stable isotope stratigraphy and astrochronology between 8.0 and 4.5 Ma. Splice revisions and verifications resulted in ∼ 11 m of gaps in the original Site 982 isotope stratigraphy, which were filled with 263 new isotope analyses. This new stratigraphy reveals previously unseen benthic δ18O excursions, particularly prior to 6.65 Ma. The benthic δ18O record displays distinct, asymmetric cycles between 7.7 and 6.65 Ma, confirming that high-latitude climate is a prevalent forcing during this interval. An intensification of the 41 kyr beat in both the benthic δ13C and δ18O is also observed ∼ 6.4 Ma, marking a strengthening in the cryosphere–carbon cycle coupling. A large ∼ 0.7 ‰ double excursion is revealed ∼ 6.4–6.3 Ma, which also marks the onset of an interval of average higher δ18O and large precession and obliquity-dominated δ18O excursions between 6.4 and 5.4 Ma, coincident with the culmination of the late Miocene cooling. The two largest benthic δ18O excursions ∼ 6.4–6.3 Ma and TG20/22 coincide with the coolest alkenone-derived sea surface temperature (SST) estimates from Site 982, suggesting a strong connection between the late Miocene global cooling, and deep-sea cooling and dynamic ice sheet expansion. The splice revisions and revised astrochronology resolve key stratigraphic issues that have hampered correlation between Site 982, the equatorial Atlantic and the Mediterranean. Comparisons of the revised Site 982 stratigraphy to high-resolution astronomically tuned benthic δ18O stratigraphies from ODP Site 926 (equatorial Atlantic) and Ain el Beida (north-western Morocco) show that prior inconsistencies in short-term excursions are now resolved. The identification of key new cycles at Site 982 further highlights the requirement for the current scheme for late Miocene marine isotope stages to be redefined. Our new integrated deep-sea benthic stable isotope stratigraphy and astrochronology from Site 982 will facilitate future high-resolution late Miocene to early Pliocene climate research.
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Johnson, Kenneth G. "Middle Miocene recovery of Caribbean reef corals: New data from the Tamana Formation, Trinidad." Journal of Paleontology 75, no. 3 (May 2001): 513–26. http://dx.doi.org/10.1017/s0022336000039639.
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Caribbean coral reef communities were restructured by episodes of accelerated biotic change during the late Oligocene/early Miocene and the late Pliocene/early Pleistocene. However, rigorous description of the effects of rapid biotic change is problematic because preservation and exposure of coral-bearing deposits is not consistent in all stratigraphic intervals. In the Caribbean, early and middle Miocene exposures are more rare than late Miocene and Pliocene exposures. One exception is the late early to early middle Miocene Tamana Formation of Trinidad, and old and new collections from this unit were studied to determine the timing of recovery after the Oligocene/Miocene transition. A total of 41 species of zooxanthellate corals were recovered from the unit, including 21 new records. Within these assemblages, species first occurrences outnumber species last occurrences by a factor of four (31 first occurrences and eight last occurrences). The extension of the stratigraphic ranges of species previously first recorded in Pliocene sediments has reduced an apparent Pliocene pulse of origination, indicating that the Pliocene/Pleistocene transition was largely a result of accelerated extinction against a background of near-constant origination. The fact that few species last occur in the Tamana fauna indicates that the Oligocene/Miocene transition was complete by the end of the early Miocene.
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Iqbal, M., D. S. Ambarsari, S. Sukmono, W. Triyoso, T. A. Sanny, E. Septama, P. D. Wardaya, R. R. Pratama, B. S. Murdianto, and R. Raguwanti. "Seismic reservoir characterization of gas-sand deposits in the Kutei basin, Indonesia." IOP Conference Series: Earth and Environmental Science 873, no. 1 (October 1, 2021): 012051. http://dx.doi.org/10.1088/1755-1315/873/1/012051.
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Abstract Kutei Basin has the second largest hydrocarbon reserve in Indonesia. In addition to the Miocene inversion related structural traps, slope-fan and channel stratigraphic traps are also important traps in this basin. To guide stratigraphic traps explorations in the basin, the seismic stratigraphy, attributes, and AI inversion methods are integrated to identify and map the reservoir seismic facies, porosity, and pore-fluid. Well data indicates that the studied reservoirs are filled by gas. Seismic data shows that there are two main gas-sand reservoirs corresponding to strong amplitude anomaly. Seismic stratigraphy analysis, guided by seismic attributes, shows that these gas-sand reservoirs were deposited in the channel and local fan facies. The AI inversion is applied to identify and map the porosity and pore-fluid of these two sand reservoirs. Future well locations are identified by integrating the facies, porosity, and pore-fluid maps.
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Cadena, Andrea F., and Roger M. Slatt. "Seismic and sequence stratigraphic interpretation of the area of influence of the Magdalena submarine fan, offshore northern Colombia." Interpretation 1, no. 1 (August 1, 2013): SA53—SA74. http://dx.doi.org/10.1190/int-2013-0028.1.
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The area of influence of the Magdalena submarine fan, offshore northern Colombia, is a global frontier basin with sparse well control and only publically available 2D seismic from which to conduct exploration surveys. We have conducted a 2D seismic stratigraphic study to advance knowledge of the tectonostratigraphic evolution of this area and, furthermore, optimize exploration concepts to include stratigraphy and sedimentology to enhance such opportunities. Eight third-order seismic sequences from the early Miocene to Holocene comprise the stratigraphic record. Seismic character, thickness, and sedimentary processes vary in each sequence based on the area of deposition. Three geomorphologic areas are subject to deposition: the Tayrona depression, the undeformed central Magdalena fan and deformed wedges on either side of the fan. From oldest to youngest, sequences I to V represent bathyal paleo-environments that were deformed during the late Miocene Andean phase. Deformation of these sequences is thin skinned thrust sheets, where the main basal detachment corresponds to Oligocene shale. This deformation continued until the middle Pliocene, when sequence VI and VII were deposited on the Magdalena Fan mainly as mass transport and channel-levee deposits. Sequence VIII represents the record from early Pleistocene to the present time. From early Pliocene to present, erosion was mainly the product of submarine fan activity and bypass in areas of high slope, whereas for older deposits, erosion was caused by exposure to subaerial conditions. Superimposed on the third-order sequences are fourth-order sequences, which reveal a relative (tectonic-eustatic) sea level increase from Early Miocene to middle Late Miocene (Tortonian) time, followed by a lowstand event that extended until Holocene time. Potential reservoirs embedded within the sequences include sheet sands, channel fills, and levee-overbank. Other components of the petroleum system such as a mature source rock are still under debate.
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Erten, Hüseyin, Sevket Sen, and Muhittin Görmüş. "Middle and Late Miocene Cricetidae (Rodentia, Mammalia) from Denizli Basin (Southwestern Turkey) and a New Species ofMegacricetodon." Journal of Paleontology 88, no. 3 (May 2014): 504–18. http://dx.doi.org/10.1666/13-060.
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The occurrences of Cricetidae and the description of a new species,Megacricetodon yenicekentensisnew species from the Denizli terrestrial Neogene Basin are considered herein. The Miocene sediments of the area mainly include terrestrial siliciclastic sediments and have a significant mammal fauna. Fieldwork was carried out in the six localities in the basin and the following rodents were identified:Cricetodon candirensis,Cricetulodon hartenbergeri,Megacricetodon minorandMegacricetodon yenicekentensisn. sp. This is the first study of rodent faunas from the Denizli Basin, which is still poorly documented. This study contributes to a better understanding of the stratigraphic and geological features of the Denizli Basin, which is one of the grabens formed within the Neotectonic period of Western Anatolia and has a significant role in explaining the tectonic evolution of the region. Its sedimentary units are, in stratigraphic order, the Kızılburun, Sazak, Kolankaya and Ulubey formations. Based on the systematics and biochronological implications of cricetids and the bulk faunas from six localities, the time range of these formations is discussed, and an age between the early middle Miocene (MN 6) and late Miocene (MN 10) is proposed for this stratigraphic succession. In addition, the dating of the Ulubey Formation, which is observed both in the Denizli and Uşak-Selendi basins, provides new data about the time of connection between these two basins.
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ZIMMT, JOSHUA B., SUSAN M. KIDWELL, ROWAN LOCKWOOD, and MATTHEW THIRLWALL. "STRONTIUM ISOTOPE STRATIGRAPHY REVEALS 100 KY-SCALE CONDENSATION, BEVELING, AND INTERNAL SHINGLING OF TRANSGRESSIVE SHELL BEDS IN THE MARYLAND MIOCENE." PALAIOS 37, no. 10 (October 20, 2022): 553–73. http://dx.doi.org/10.2110/palo.2022.004.
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Abstract Condensed transgressive shell beds, rich in paleobiological information, are common in the Phanerozoic stratigraphic record, but their interpretation is complicated by the uncertain amount of time that each deposit represents. Miocene strata exposed in the Calvert Cliffs (Maryland, USA) are known for a series of regionally extensive, densely packed, meters-thick shell beds that serve as global exemplars of shallow-water condensation during marine transgression and onlap. Applying Sr isotope stratigraphy to calcitic scallops from the base and top of the oldest of these beds (Shattuck Zone 10), we demonstrate that its most densely fossiliferous part accumulated over the interval of 16.60–15.95 Ma, reflecting approximately 0.65 ±0.20 Myr of skeletal accumulation within the Miocene Climatic Optimum, with a likely 0.15 Myr-scale of time averaging per each firmground-bounded subunit. Both of these estimates are an order of magnitude longer than previous best estimates based on radiocarbon-dated Holocene analogs. Sr isotopes confirm subtle low-angle erosional beveling of the main body of Zone 10, truncating 0.3-Myr of record in updip sections, and demonstrate that a down-dip wedge of less shelly sand is an entirely younger (by ∼ 0.5 Myr) interleaved body. This condensation, beveling, and inter-shingling within Zone 10 quantified here sets a precedent for the magnitude of lateral and vertical temporal variability within condensed transgressive deposits, relevant to paleobiologic and other geohistorical analysis, and justifies the interpretation of comparably complex temporal fabrics based upon similar physical stratigraphic features found elsewhere in this and other very thin stratigraphic records.
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Zeng, Hongliu, and Milo M. Backus. "Interpretive advantages of 90°-phase wavelets: Part 2 — Seismic applications." GEOPHYSICS 70, no. 3 (May 2005): C17—C24. http://dx.doi.org/10.1190/1.1925741.
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We examine field seismic data to test the benefits of 90°-phase wavelets in thin-bed interpretation that are predicted by seismic modeling in part 1 of this paper. In an interbedded sandstone-shale Miocene succession in the Gulf of Mexico basin, a 90°-phase shift of nearly zero-phase seismic data significantly improves lithologic and stratigraphic interpretation. A match between seismic and acoustic impedance (AI) profiles results in a better tie between seismic amplitude traces and lithology-indicative logs. Better geometric imaging of AI units that does not use dual-polarity seismic events results in easier and more accurate reservoir delineation. Less amplitude distortion and the stratigraphy-independent nature of thin-bed interference significantly improves stratigraphic resolution and seismic stratigraphic profiling. For a Ricker-like wavelet having small side lobes, stratigraphic resolution of 90°-phase data is considerably higher than that of zero-phase data. In this specific case, stratigraphic resolution of 90°-phase data is λ/4 (λ = wavelength), compared with λ/2 for its zero-phase counterpart. Stratal slices made from 90°-phase data show geomorphologic patterns of depositional systems with less noise and fewer interference fingerprints. A Permian Basin field provides a real-world example of porous zones in thin, high-frequency carbonate sequences that are better visualized with 90°-phase seismic data than with zero-phase data.
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Osokpor, Jerry, and Efetobore G. Maju-Oyovwikowhe. "Paleodepositional Environment and Sequence Stratigraphy of Miocene Sediments in Well TN-1, Coastal Swamp Depobelt, Niger Delta Basin, Nigeria." Tanzania Journal of Science 47, no. 5 (December 1, 2021): 1530–45. http://dx.doi.org/10.4314/tjs.v47i5.4.
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This research focused on the interpretation of paleodepositional environment and development of a sequence stratigraphic framework for the well TN-1 section, located in the coastal swamp depositional belt of the Niger Delta Basin. Integration of interpreted litho- and biofacies data sets that facilitated the interpretation of the paleodepositional environment enabled the erection of a sequence-stratigraphic framework. Three lithotypes (sand, clay, and shale) distributed within fourteen facies variants were integrated with palynomorph components to delineate five paleodepositional cycles ranging from distal delta plain to bathyal. Eight systems tracts (closely related to depositional cycles, but transcended depositional boundaries in some intervals) that hosted three maximum flooding surfaces (MFS), three sequence boundaries (SBs), distributed within four third-order and three second-order sequences, were defined. Age-significant palynomorphs recovered indicated an Aquitanian to Messinian age range (with non-deposition or erosion of Burdigalian, Langhian, Serravallian Stages sediments), distributed within five pollen zones (P628–P840) that correlated with published global cycles. This study demonstrates the significance of integrated studies to erect a sequence-stratigraphic framework applicable for field and basin-scale exploration and exploitation purposes.
Keywords: Sequence stratigraphy, paleodepositional cycles, systems tract, cyclic sedimentation,lithofacies analysis, integrated studies.
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CULVER, STEPHEN J., SETH R. SUTTON, DAVID J. MALLINSON, MARTIN A. BUZAS, MARCI M. ROBINSON, and HARRY J. DOWSETT. "MIOCENE NERITIC BENTHIC FORAMINIFERAL COMMUNITY DYNAMICS, CALVERT CLIFFS, MARYLAND, USA: SPECIES POOL, PATTERNS AND PROCESSES." PALAIOS 36, no. 7 (July 19, 2021): 247–59. http://dx.doi.org/10.2110/palo.2020.069.
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ABSTRACT The presence/absence and abundance of benthic foraminifera in successive discrete beds (Shattuck “zones”) of the Miocene Calvert and Choptank formations, exposed at the Calvert Cliffs, Maryland, USA, allows for investigation of community dynamics over space and time. The stratigraphic distribution of benthic foraminifera is documented and interpreted in the context of sea-level change, sequence stratigraphy, and the previously published distribution of mollusks. Neritic benthic foraminiferal communities of four sea-level cycles over ∼4 million years of the middle Miocene, encompassing the Miocene Climatic Optimum and the succeeding middle Miocene Climate Transition, are dominated by the same abundant species. They differ in the varying abundance of common species that occur throughout most of the studied section and in the different rare species that appear and disappear. Transgressive systems tracts (TSTs) have higher species diversity than highstand systems tracts (HSTs) but much lower density of specimens. In contrast to some previous research, all beds in the studied section are interpreted as being from the inner part of a broad, low gradient shelf and were deposited at water depths of less than ∼50 m. It is suggested that species are recruited from a regional species pool of propagules throughout the duration of TSTs. Recruitment is curtailed during highstands leading to lower diversity in the HSTs.
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Vrsaljko, Davor, Davor Pavelić, and Zlatan Bajraktarević. "Stratigraphy and Palaeogeography of Miocene Deposits from the Marginal Area of Žumberak Mt. and the Samoborsko Gorje Mts. (Northwestern Croatia)." Geologia Croatica 58, no. 2 (2005): 133–50. http://dx.doi.org/10.4154/gc.2005.07.
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Miocene sediments rimming the Palaeozoic–Mesozoic–Palaeogenerocks, form Žumberak Mt. and the Samoborsko Gorje Mts. Spatialanalysis of the setting and development of the surface Miocenestratigraphy, at the marginal areas of the Žumberak and SamoborskoGorje Mts., allows four palaeogeographic areas to be distinguished:Žumberak, Plešivica–Sveta Jana, Samobor–Sveta Nedelja and Grdanjci.In the Miocene deposits (totaling 350 m), within the area ofŽumberak, coarse-grained clastics from deltaic deposits of Pannonianage prevail. Here only, 50 m of sediments of Pliocene–Pleistoceneage overlie the Miocene deposits whereas Mesozoic carbonates representthe basement. The Plešivica–Sveta Jana area is characterizedby a 600 m sequence of Miocene deposits, mainly overlying Triassicdolomites, where finely-grained layers of marls and silts prevail.In this area, Miocene successions from the Badenian to the Pontianare characterized by a continuity of sedimentation with an inheriteddepositional environment. In the area of Samobor–Sveta Nedelja,the basement is diverse: Triassic dolomites, volcanogenic–sedimentarycomplex of Cretaceous age and a clastic–carbonate complex ofPalaeogene age. The Miocene succession shows a regressive trendfrom the Badenian to the Pontian and the total thickness is estimatedat 400 m. The area of Grdanjci differs considerably from the otherMiocene palaeorelief. An approximately 50 m-thick series of coarsegrained clastics with coal is distinguished, of unclear stratigraphic age (Ottnangian?). Miocene sediments of the Grdanjci area are represented by both a transgressive type of conglomerates and shallow water limestones of Badenian age, with a total thickness of about 100 m.The development of the Miocene stratigraphy of the Žumberakand Samoborsko Gorje Mts. is generally correlative with that in theother parts of the Pannonian area, though it does exhibit local variations.Comparison of the Miocene palaeorelief of Žumberak Mt. withthe Samoborsko Gorje Mts., together with neighbouring areas, enabledwider correlation with other parts of northern Croatia, and themore distant Western and Central Paratethys.
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Del Río, Claudia-J., and Sergio Martínez. "Diversity and biostratigraphy of the late Oligocene-late Miocene sand dollars (Echinoidea: Scutelliformes) of Argentina and Uruguay." Revista de Biología Tropical 69, Suppl.1 (March 22, 2021): 35–50. http://dx.doi.org/10.15517/rbt.v69isuppl.1.46324.
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Introduction: Scutelliforms were diverse and widespread in shallow marine environments during Neogene times in South America. Nevertheless, they have almost never been used as biostratigraphic tools. Objective: To provide a refined stratigraphic frame useful for calibrating temporal dimensions of scutelliform diversity from Argentina and Uruguay and its correlation with the molluscan assemblages previously proposed. Methods: A detailed survey of their geographic and stratigraphic provenance was carried out. We revised both the bibliography and collections (institutional and from our own field work). Results: The group is represented by 14 species belonging to six genera, and four assemblages were identified. Numerical dates of the Neogene marine rocks obtained recently allowed their placement in a chronological scheme: “Iheringiella” sp. A is restricted to the late Oligocene, the genera Camachoaster and “Eoscutella” and the species Monophoraster telfordi to the early Miocene, Abertella gualichensis and Abertella miskellyi to the middle Miocene, and Monophoraster duboisi, Amplaster coloniensis and Amplaster ellipticus to the late Miocene. Non-lunulate scutelliforms are not restricted to the late Oligocene as previously supposed. The oldest occurrence of the genus Monophoraster corresponds to the early Miocene, and along with Iheringiella are long-living taxa that embrace the 25.3 Ma-18.1 Ma (Iheringiella patagonensis) and approximately 15 Ma-6.48 Ma (Monophoraster darwini) intervals. The presence of Iheringiella in the early Miocene of northeastern Patagonia is corroborated, reaching there its northernmost distribution. Monophoraster darwini has a temporal range from the late Miocene (where it was previously thought to be restricted) back to the middle Miocene, since this is the species yielded in the well-known and discussed “Monophoraster and Venericor Beds”. Conclusions: The Paleogene-Neogene scutelliforms of Argentina and Uruguay range from the late Oligocene to the late Miocene. There is a good correspondence among the numerical ages, molluscan biozones and scutelliform assemblages.
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Ramanujam, C. G. K., P. R. Reddy, and H. Ramakrishna. "Surmaspora Singh & Rao from the Neogene sediments of southern India: its stratigraphic and botanical significance." Journal of Palaeosciences 46, no. 3 (December 31, 1997): 47–50. http://dx.doi.org/10.54991/jop.1997.1347.
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The paper deals with the occurrence of Surmaspora (S. karii) from the subsurface Miocene sediments of Godavari Basin in Andhra Pradesh and Cauvery Basin in Tamil Nadu and highlights its stratigraphic and botanical significance.
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de Santana dos Anjos Zerfass, Geise, Dmitry A. Ruban, Farid Chemale Jr., and Henrique Zerfass. "Cenozoic synthem stratigraphic architecture of the SE Brazilian shelf and its global eustatic context: evidence from the Pelotas Basin (offshore Brazil)." Geologos 19, no. 4 (December 1, 2013): 273–90. http://dx.doi.org/10.2478/logos-2013-0018.
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Abstract The Pelotas Basin, located on the SE Brazilian shelf, has evolved since the Aptian. Stratigraphical data from the basin can be used for delineation of the unconformity-bounded units (synthems) on the shelf, which is a first step towards a full understanding of its stratigraphic architecture, evolution, and hydrocarbon potential. Hiatuses in the Cenozoic succession of the Pelotas Basin are established with both biostratigraphic (planktonic foraminifers and calcareous nannofossils) and isotopic (87Sr/86Sr) data. The seven recognised hiatuses are dated respectively as (1) Palaeocene (Danian- Thanetian), (2) Palaeocene/Eocene boundary (Thanetian-Ypresian), (3) Eocene (Ypresian-Lutetian), (4) Eocene-Oligocene (Lutetian-Rupelian), (5) early-late Oligocene (Rupelian-Chattian), (6) early Miocene (Aquitanian-Burdigalian), and (7) middle-late Miocene (Serravallian-Tortonian). These intervals between the hiatuses are correlated with those of the Santos and Campos Basins north from the Pelotas Basin. The breaks in sedimentation that these basins have in common occurred (1) at the Palaeocene-Eocene and (2) Eocene-Oligocene transitions, (3) in the early Miocene, and (4) in the middle-late Miocene. These main unconformities outline five synthems on the SE Brazilian shelf, viz. the SEBS-1 (Palaeocene), SEBS-2 (Eocene), SEBS-3 (Oligocene), SEBS-4 (early-middle Miocene) and SEBS-5 (late Miocene-Holocene). The above unconformities are correlated with those established in the Cenozoic sedimentary successions of different regions such as Western Siberia, Arabia, NW and NE Africa, peninsular India, S Australia, the Gulf of Mexico, NW Europe, and South Africa. The only regional unconformity, near the Oligocene/Miocene boundary, coincides with the nearly-global sedimentation break. The latter was resulted from a climatic event, i.e., the ‘Mi-1 glaciation’. Thus, a eustatic origin is supposed for this regional unconformity. The other regional unconformities also correspond to global sea-level falls (probably with an exception for the Palaeocene/Eocene surface), which suggests that global eustatic movements controlled the development of the regional synthem architecture.
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Krizmanić, Krešimir, Krisztina Sebe, and Imre Magyar. "Dinoflagellate cysts from the Pannonian (late Miocene) "white marls" in Pécs-Danitzpuszta, southern Hungary." Földtani Közlöny 151, no. 3 (December 4, 2021): 267–74. http://dx.doi.org/10.23928/foldt.kozl.2021.151.3.267.
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Dinoflagellate-cyst based biostratigraphy is an important tool in the stratigraphical subdivision and correlation of the Neogene Lake Pannon deposits. A total of 66 palynological samples were investigated from the Pannonian (upper Miocene) marl succession exposed in the Pécs-Danitzpuszta sand pit in order to evaluate the biostratigraphical assignment and constrain the age of the strata. Earlier attempts to recover dinoflagellate cysts from this important reference section had failed. In our material, six samples contained well-preserved palynomorphs. One sample from the lower part of the succession (D25) contained a probably reworked middle Miocene assemblage. Samples from the middle segment of the succession (D3, D2, D1) indicate the Pontiadinium pecsvaradensis Zone (ca. 10.8 to 10.6 Ma). Samples from the top of the marl (D219, D221) did not give additional stratigraphic information (P. pecsvaradensis Zone or younger). The palynofacies of samples D3 to D221 indicates a relatively distal, calm, occasionally oxygen-deficient, probably deep depositional environment.
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Alvan, Aldo A., Yacory F. Bustamante, Elvis A. Sánchez, and Mirian I. Mamani. "Arquitectura estratigráfica, paleogeografía y proveniencia sedimentaria de las rocas cenozoicas del sur de Perú (Tacna, 18° S)." Andean Geology 47, no. 2 (May 29, 2020): 351. http://dx.doi.org/10.5027/andgeov47n2-3168.
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The Cenozoic rocks lying in the Province of Tacna (18° S), southern Perú, represent approximately 600 m of stratigraphic thickness. This stacking groups the Sotillo (Paleocene), Moquegua Inferior (Eocene), Moquegua Superior (Oligocene), Huaylillas (Miocene) and Millo formations (Pliocene), and these are the sedimentary fill of the Moquegua Basin. The sediments of the three latter formations are organized into nine sedimentary facies and five architectural elements. Their facies associations suggest the existence of an ancient highly channelized multi-lateral fluvial braided system, with upward increase of pyroclastic and conglomeratic depositions. The heavy mineral spectra make each lithostratigraphic unit unique and distinguishable, being the sediments of the Moquegua Superior Formation rich in garnets, titanites and zircons; while the sediments of the Huaylillas and Millo formations in clinopyroxenes. This mineral arrangement becomes an excellent tool for stratigraphic correlations between outcrops and subsurface stratigraphy (by means of well cores studies) and allow to sketch out a new stratigraphic framework and a complex of rocky blocks bounded by normal faults, often tilted. The sediment mineralogy also suggests that the rocks conforming the Western Cordillera were the main source of sediments for the Moquegua Basin in Tacna. In this context, the detritus of the Moquegua Superior Formation derives mainly from the erosion of the rocks forming the Coastal Basal Complex (Proterozoic), the Ambo Group (Carboniferous) and the Junerata/Chocolate Formation (Early Jurassic). The Huaylillas Formation is a pyroclastic and sedimentary unit which components derived mainly from the Huaylillas volcanism (Miocene) and partly from the denudation of the Toquepala Group (Late Cretaceous). The Huaylillas Formation widely contrasts to the underlying Moquegua Superior Formation due its mineralogy and facies. Finally, the detritus of the Millo Formation derived mostly from the rocks forming the Barroso Formation (Pliocene), and their facies represent a higher contrast in relation to the underlying units due its notorious conglomerate facies.
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Bayshashov, B. U., E. A. Tokpanov, G. Zh Nurgalieva, and N. B. Abubakirova. "Oligocene, miocene fossil animals of the river valley maitobe (South-East Kazakhstan) and their biostratigraphic and paleoecological positions." Kazakhstan zoological bulletin 1, no. 1-2 (2020): 68–75. http://dx.doi.org/10.54944/kzbdn725ys58.
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The article discusses the importance of the study of fossil animals for the reconstruction of the landscape and climatic conditions of the past, on the example of the study of fossil fauna and the biostratigraphic, paleoecological position of the deposits of the Kogaly intermountain depression of the Maitobe river valley of the Kyzylzhar geological section. As a result of the latest research, it became clear that the fossil animals from Kyzylzhary belong to two separate stratigraphic levels. As a result of the latest research, it became clear that the fossil animals from Kyzylzhary belong to two separate stratigraphic levels. The bones of the rhinoceros - Paraceralherum zhajremensis Bayshashov, 1988 were found in the yellow sands of the Upper Oligocene, and the Aceratherium aralense Borissiak, 1944 - in gravelly sands with gravelites, conglomerates of the Lower Miocene. Previously, here the fossil fauna was referred to one stratigraphic level - from the beginning, as in Saryozek in the Lower Miocene (Bazhanov and Kostenko, 1958; Savinov, 1963; Bayshashov, 1990), then, as in the Zhajrem and Aktau localities, the Upper Oligocene (Bayshashov, 2009). In addition, a description of the bone Paraceratherum zhajremensis discovered later is given.
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Luan, Xiwu, and Peter Lunt. "Eocene to Miocene stratigraphic controls in the far East Java Sea: Implications for stratigraphic studies." Marine Geology 436 (June 2021): 106479. http://dx.doi.org/10.1016/j.margeo.2021.106479.
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Pasini, Giovanni, Antonio De Angeli, and Alessandro Garassino. "Calappa praelata Lőrenthey in Lőrenthey & Beurlen, 1929 (Decapoda, Brachyura, Calappidae) from the Middle Miocene of Tresnuraghes (Oristano, Sardegna, Italy)." Natural History Sciences 153, no. 1 (January 1, 2012): 135. http://dx.doi.org/10.4081/nhs.2012.135.
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We report <em>Calappa praelata</em> Lőrenthey in Lőrenthey & Beurlen, 1929 (Calappidae De Haan, 1833), based upon one single carapace, three-dimensionally preserved, from the Middle Miocene of Tresnuraghes (Oristano, Sardegna, Italy). It is the first record of this species in Sardegna and Italian territory, enlarging the knowledge of distribution and its stratigraphic range in the paleo-Mediterranean basin. The species is already known from Middle-Upper Miocene of Hungary, Poland, Austria, Malta, and Spain.
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Pham, Thi Duyen, Hoang Dam Mai, Thi Hoa Ta, Van Su Nguyen, and Thi Tham Nguyen. "Distribution of larger benthic foraminifera from Miocene carbonates in the Center and Southeast of the Nam Con Son basin." Petrovietnam Journal 11 (December 16, 2022): 19–32. http://dx.doi.org/10.47800/pvj.2022.11-02.
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In biostratigraphical studies, the planktonic foraminifera, nannofossils, and palynomorphs are recorded rarely in shallow water limestones. Meanwhile, larger benthic foraminifera (LBF) have an important role in defining the stratigraphic range and the depositional environment of carbonate formations is recorded abundantly. The precise identification of LBF’s taxonomy depends on the recognition of its internal structures using polarised microscopes.
Results from the study in the Central and South-eastern Nam Con Son basin show that LBF occurred frequently in the Miocene and, especially, became extremely dominant in the Middle Miocene. In the Early Miocene (Te5 - lower Tf1), they appeared sparsely in the Te5 but became abundant in the lower Tf1. In the Middle Miocene (middle Tf1 - Tf3), they were predominant and diverse in many genera and species, marked by the disappearance of Miogypsina, Miogypsinoides, Katacycloclypeus, and most of the species of Lepidocyclina and Cycloclypeus at the top of the sub-epoch. In the Late Miocene (Tg), LBF was not varied, mainly Amphistegina and Operculina. However, some significant species of the genus Lepidocyclina were extant and dwelled on the isolated carbonate platforms in the Southeast area of the basin. The association of larger benthic foraminifera with small millioids and rotalids, planktonic foraminifera, coral, and/or algae, crinoids, bivalves, etc., may implicate the palaeoenvironmental zone of the carbonate deposits in the wells of the studied region, ranging from the lagoon, shelves surrounding reef to relatively deep, open marine conditions. The occurrence of LBF in carbonate deposits is the key to defining the age, identifying the stratigraphy and depositional environment, and correlating the carbonates.
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Abd El-Naby, Ahmed I. M., Hussam Ghanem, Mohamed Boukhary, Mohamed H. Abd El-Aal, Sebastian Lüning, and Jochen Kuss. "Sequence-stratigraphic interpretation of structurally controlled deposition: Middle Miocene Kareem Formation, southwestern Gulf of Suez, Egypt." GeoArabia 15, no. 3 (July 1, 2010): 129–50. http://dx.doi.org/10.2113/geoarabia1503129.
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ABSTRACT The structural evolution and sequence-stratigraphic architecture of the syn-rift Middle Miocene (Langhian) Kareem Formation were studied in the Western Sub-Basin (WSB) of the Gulf of Suez, Egypt. Biostratigraphic data, facies interpretations, and log data from thirteen wells were used to construct six tectono-sedimentary scenarios and lithofacies-distribution maps, which illustrate the paleogeography during six systems tracts. Abrupt thickness and facies changes reflect deep basins and adjacent high-relief areas created by differential fault-block movements. Within the WSB seven individual fault blocks record complex, tectonically controlled deposition of the Kareem Formation, which we subdivide into two third-order sequences. Earlier tectonic interpretations, facies analysis, and stratigraphic correlations from individual fault blocks were used to interpret the varying depositional settings during six systems tracts and, as a consequence, to discern the structural evolution of the WSB during the Middle Miocene.
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Rasmussen, Erik S., Karen Dybkjær, and Stefan Piasecki. "The Billund delta: a possible new giant aquifer in central and western Jutland." Geological Survey of Denmark and Greenland (GEUS) Bulletin 4 (July 20, 2004): 21–24. http://dx.doi.org/10.34194/geusb.v4.4773.
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The search for new, deep-seated drinking water resources in Denmark has increased significantly during the past five years as a result of the discovery of excessive amounts of nitrate, pesticides and other pollutants in shallow groundwater boreholes (e.g. Nygaard et al. 2004, this volume). To find and map these aquifers, a multidisciplinary sequence stratigraphic approach has successfully been applied to the Miocene deposits of southern Jutland, where especially the Odderup and Ribe Formations are known as a main aquifer for drinking water from several test wells (Rasmussen et al. 2002). Recently, a more systematic study of the Miocene succession in central and western Jutland has been initiated by the Geological Survey of Denmark and Greenland (GEUS) under contract with local authorities. It includes detailed sedimentological descriptions of outcrops, sedimentological andlog-interpretations of new stratigraphic boreholes and interpretation of new high-resolution seismic data (Fig. 1). A number of outcrops and wells have been studied palynologically, resulting in a detailed dinoflagellate cyst stratigraphy and in palynofacies interpretations. The results of these studies have been integrated in the regional geological and stratigraphic model (Fig. 2). Two new aquifers have been discovered: the Bastrup sand and the Billund sand. The Bastrup sand has already been exploited as a main aquifer in central and southern Jutland, and has been referred to either the Ribe or Odderup Formations. However, new stratigraphic results reveal that the Bastrup sand is a separate unit in the Miocene succession. The Billund sand is a deep-seated aquifer located more than 100 m and often more than 150 m deep, and is therefore not penetrated by standard water supply wells which rarely reach c. 100 m. The Billund sand was first revealed by multichannel seismic data deriving from former oil-exploration carried out in the Billund area (Fig. 3A). The resolution of these seismic data is very poor, but one interpretation of the dipping reflectors (clinoforms) seen in Fig. 3A was of a delta complex. This agrees with outcrop studies along the fjords of eastern Jutland which suggest that a spit complex was deposited in this area during the Early Miocene. The Billund sand was tested by the Vandel Mark well in 2001, which penetrated c. 40 m of sand at a depth of 200 m. The presence of a regional major sand body was later confirmed by new high-resolution seismic data and by the Billund and Løvlund wells in 2002. The Billund well penetrated 50 m of medium- to coarse-grained sand, and chemical tests of the water quality were good. However, a water supply well at Fjand in western Jutland has had problems with so-called ‘brown water’ – water enriched in organic matter (humus). Saline water may also be expected close to older deep-seated faults. This paper summarises the results of a mapping programme of the Billund sand initiated in the summer of 2003.
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Barbieri, Roberto, and Gian Gabriele Ori. "<i>Globorotalia bouregregensis,</i> a new species of planktonic foraminifer from the latest Miocene–early Pliocene of the Rifian Seaway (northwest Morocco)." Journal of Micropalaeontology 16, no. 2 (October 1, 1997): 175–78. http://dx.doi.org/10.1144/jm.16.2.175.
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Abstract. Globorotalia bouregregensis, n. sp., is described and documented from the latest Miocene-early Pliocene sequence of the Rifian Seaway, northwest Morocco. By its short stratigraphic distribution, persistence and distinctive morphologic features, the new taxon is well differentiated within the scituline assemblage.
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Pashko, Pandeli. "Morave Mt Oligocene-Middle Miocene succession of Albanian-Thessalian Basin." Bulletin of the Geological Society of Greece 52, no. 1 (September 28, 2018): 1. http://dx.doi.org/10.12681/bgsg.15837.
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The Morava Mountain Oligocene-Middle Miocene molasse deposits take part in the Albanian-Thessalian Basin, which developed NW-SE from eastern Albania to Thessaly in Greece, where it is called as Mesohellenic Basin. The 4.5 km thick basin infill is subdivided into three molasse cycles separated by two regional unconformities at the Eocene/Oligocene and Aquitanian/Burdigalian boundaries. The Morava Mountain Oligocene-Middle Miocene molase, ~ 3500 m thick, represents an exposed continuous, rich in fossil fauna succession. Six stratigraphic sections were studied and measured.
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Leroux, Estelle, Marina Rabineau, Daniel Aslanian, Christian Gorini, François Bache, Maryline Moulin, Romain Pellen, Didier Granjeon, and Jean-Loup Rubino. "Post-rift evolution of the Gulf of Lion margin tested by stratigraphic modelling." Bulletin de la Société Géologique de France 186, no. 4-5 (July 1, 2015): 291–308. http://dx.doi.org/10.2113/gssgfbull.186.4-5.291.
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AbstractThe sedimentary architecture of basins and passive margins is determined by a complex interaction of parameters, including subsidence, eustasy, and sediment supply. A quantification of the post-rift (20 Ma-0 Ma) vertical movements of the Gulf of Lion (West Mediterranean) is proposed here based on the stratigraphic study of sedimentary paleomarkers using a large 3D grid of reflection seismic data, correlations with existing drillings, and refraction data. Post-rift subsidence was measured by the direct use of sedimentary geometries analysed in 3D and validated by numerical stratigraphic modelling. Three domains of subsidence were found: on the continental shelf and slope, subsidence corresponds to a seaward tilting with different amplitudes, whereas the deep basin subsides purely vertically. We show that these domains fit with the deeper crustal domains highlighted by previous geophysical data, and that post-break-up subsidence follows the initial hinge lines of the rifting phase. Subsidence rates are quantified on each domain for each stratigraphic interval. At a constant distance from the rotational hinge line, the Plio-Quaternary subsidence rate is constant on the shelf overall. Conversely, Miocene subsidence rates are very different on the eastern and western shelves. Stratigraphic simulations focused on the Messinian salinity crisis (MSC) were also performed. Their results are discussed together with our post-rift subsidence estimates in order to provide ideas and hypotheses for future detailed quantifications of Miocene subsidence, including isostatic readjustments linked to the MSC.
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Pasini, Giovanni, Alessandro Garassino, and Marco Sami. "Decapod assemblage from the late Miocene (early-middle Messinian) of the Romagna Apennines nearby Brisighella, Emilia-Romagna (N Italy)." Natural History Sciences 6, no. 1 (March 18, 2019): 27–32. http://dx.doi.org/10.4081/nhs.2019.394.
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An assemblage of axiidean and brachyuran decapods is reported from the late Miocene pre-evaporitic (early-middle Messinian) limestone of Cò di Sasso, nearby Brisighella (Ravenna, Emilia- Romagna), located in Romagna Apennines (NE Italy). Except Monodaeus bortolottii Delle Cave, 1988 (Xanthidae MacLeay, 1838), which is reported here for the first time in Miocene, all the other specimens have been assigned to species previously known in the Italian Miocene (Messinian s.l.), but never reported in this area. The report of Galathea cf. G. weinfurteri Bachmayer, 1950 (Galatheidae Samouelle, 1819) and Medorippe ampla Garassino, De Angeli, Gallo and Pasini, 2004 (Dorippidae MacLeay, 1838) enlarges the stratigraphic range of these Miocene species. This report enlarges our limited knowledge on the composition and distribution of the axiidean, anomuran, and brachyuran decapods during the early-middle Messinian before the evaporitic event in the Mediterranean Basin.
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Volkonskaya, A. L., I. N. Kerusov, A. I. Konyukhov, E. E. Karnyushina, O. V. Krylov, and G. A. Kalmykov. "Model of the structure of upper Miocene productive deposits odoptu area of the Okhotsk sea." Moscow University Bulletin. Series 4. Geology, no. 4 (August 28, 2017): 48–53. http://dx.doi.org/10.33623/0579-9406-2017-4-48-53.
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Using the example of lower nutovsky thickness on Odoptu field discusses the possibility and efficacy of sequence-stratigraphic approach to integrated interpretation of seismic data and drilling materials. Sequence stratigraphic model, graph showing sea level changes and regional chronostratigraphic correlation chart with reference to the existing geochronological scale was developed for the formation of the sedimentary cover in the research area.
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Slupik, A. A., F. P. Wesselingh, A. C. Janse, and J. W. F. Reumer. "The stratigraphy of the Neogene-Quaternary succession in the southwest Netherlands from the Schelphoek borehole (42G4-11/42G0022) – a sequence-stratigraphic approach." Netherlands Journal of Geosciences - Geologie en Mijnbouw 86, no. 4 (December 2007): 317–32. http://dx.doi.org/10.1017/s0016774600023556.
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AbstractWe investigate the stratigraphy of Neogene and Quaternary intervals of the Schelphoek borehole (Schouwen, Zeeland, the Netherlands). The Breda Formation (Miocene-Zanclean) contains three sequences separated by hiatuses. The Oosterhout Formation (Zanclean-Piacenzian) contains at least two sequences. This formation is overlain by seven sequences of the Gelasian Maassluis Formation that almost certainly represent glacial cycles. The three lowermost sequences are provisionally assigned to the Praetiglian (MIS 96, MIS 98 and MIS 100). A large hiatus exists between the top of the Maassluis Formation and the base of the late Middle to Late Quaternary succession. Due to extensivein situreworking of older strata (including fossils) at the base of several of the formations, their exact boundaries are difficult to establish. The Neogene succession in the Schelphoek borehole is compared to the stratigraphic successions in the Antwerp area to the south and the Dutch coastal area and continental platform to the north. Finally, the stratigraphic context of the Gelasian (‘Tiglian’) mammal fauna dredged from the bottom of a major tidal channel in the adjacent Oosterschelde is assessed by comparison with the Schelphoek borehole.
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Dybkjær, Karen, and Erik Skovbjerg Rasmussen. "Palynological dating of the Oligocene – Miocene successions in the Lille Bælt area, Denmark." Bulletin of the Geological Society of Denmark 47 (December 31, 2000): 87–103. http://dx.doi.org/10.37570/bgsd-2000-47-07.
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A new geological model for the succession outcropping in the Lille Bælt area, Denmark, is proposed. The model is based on dinoflagellate cyst stratigraphy on the three sections at Hindsgavl, Hagenør and Rønshoved combined with earlier biostratigraphic studies and sequence stratigraphic correlation of outcrops and borings. Our results indicate that there have been two periods with lagoonal and nearshore marine deposition in the Lille Bælt area separated by a hiatus of at least 3.5 million years. The first period occurred in Late Oligocene or earliest Early Miocene (early Aquitanian) time and is represented by the deposits at Hindsgavl. The second period occurred in Early Miocene (early to mid-Burdigalian) time and is represented by the deposits at Hagenør and Rønshoved. The deposits at Hindsgavl are time equivalent with the lagoonal upper part of the Vejle Fjord Formation and the overlying nearshore marine sand at Hvidbjerg. The deposits at Hagenør and Rønshoved correlate with the lower part of the offshore marine Arnum Formation and thus represent part of the coastline during the early to mid-Burdigalian.
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RAUSCH, LEA, MARIUS STOICA, and SERGEI LAZAREV. "A LATE MIOCENE – EARLY PLIOCENE PARATETHYAN TYPE OSTRACOD FAUNA FROM THE DENIZLI BASIN (SW ANATOLIA) AND ITS PALAEOGEOGRAPHIC IMPLICATIONS." Acta Palaeontologica Romaniae, no. 16 (2) (April 22, 2020): 3–56. http://dx.doi.org/10.35463/j.apr.2020.02.01.
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The upper Miocene – lower Pliocene sedimentary succession of the Denizli Basin (SW Anatolia) displays a unique record of undisturbed stratigraphy and provides an excellent opportunity to study long-term palaeoecological changes. This paper documents the ostracod assemblages of two sections of the Neogene Kolankaya Formation, resulting in the following taxonomic, palaeobiogeographic and ecological interpretations. The ostracod assemblages from the two sections consist of a mixture of oligohaline to mesohaline tolerant taxa but expose fundamental differences in their composition. This is reflected by the fact that out of 32 determined species, both sections only have 3 in common. In the stratigraphic older succession, the diverse ostracod fauna resembles taxa known from the Paratethys. Faunal relations to the brackish lake habitats of the Euxinic and Pannonian basins are apparent and the palaeobiogeographic significance of the fauna is discussed. The ostracod association of the younger section indicates a low brackish water habitat with fluctuating salinities, most likely in the oligohaline range. The ostracod assemblage of the Kolankaya Formation only permits a broad age assignment to the late Miocene – early Pliocene.
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Natasia, Nanda, Ildrem Syafri, Muhammad Kurniawan Alfadli, and Kurnia Arfiansyah. "Stratigraphy Seismic and sedimentation Development of Middle Baong Sand, Aru Field, North Sumatera Basin." Journal of Geoscience, Engineering, Environment, and Technology 1, no. 1 (December 1, 2016): 51. http://dx.doi.org/10.24273/jgeet.2016.11.7.
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This paper defines the stratigraphic sequence focused on Middle Baong Sand. The analyses aim to understand the sedimentation pattern regarding to sequence stratigraphy model including its lateral and vertical succession based on seismic and well data. The study can be used in ranking the prospect for new oil field. Based on the analyses in 39 seismic sections and 2 wireline log, the area are consist of three depositional sequences, namely sequence I (consist of HST I) Sequence II (consist of TST II and LST II), and Sequence III (consist of TST III). Baong Formation are deposited when the sea level are rising regionally at Middle Miocene (N7-N15) makes the sediment deposited in deep water environment. while Middle Baong Sand are deposited in the minor falling stage placed at N13 (Middle of Middle Miocene). In this episode, there is a change in depositional setting from bathyal to middle neritic. Clastic origin of this deposits were interpreted came from South-South West direction or from Bukit Barisan where at that time is started to uplift.
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Young, H. C., N. M. Lemon, and J. N. F. Hull. "THE MIDDLE CRETACEOUS TO RECENT SEQUENCE STRATIGRAPHIC EVOLUTION OF THE EXMOUTH-BARROW MARGIN, WESTERN AUSTRALIA." APPEA Journal 41, no. 1 (2001): 381. http://dx.doi.org/10.1071/aj00018.
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Five supersequences have been revealed by a regional sequence stratigraphic study conducted in the Albian (109 Ma) to Recent section of the Exmouth-Barrow passive margin. The interpretation utilises a new sequence stratigraphic model developed for mixed siliciclasticcarbonate lithofacies. A high degree of resolution is brought to the study by identification of 37 regional sequence boundaries controlled by biostratigraphic, wireline and seismic data. Ditch cutting analysis, integrated into the new chronostratigraphic framework, provided detailed lithofacies maps.The five supersequences, named the Gallic, Senonian, Palaeogene, Middle Neogene and Pliocene, are based upon regional lowstand, transgressive and highstand phases. The Gallic Supersequence (late Tithonian–latest Cenomanian) represents a marine incursion of siliciclastic sediments coincident with the rifting and accelerated movement of India away from Australia. A Senonian Supersequence (latest Cenomanian–middle Maastrichtian) truncates the previous supersequence with incised canyons developed on the outer shelf. The evolution of the Senonian section corresponds to the Australian separation from Antarctica and the first appearance of carbonates.The Palaeogene Supersequence (middle Maastrichtian– late Early Miocene) dominates much of the Tertiary and is identified by a basinward shift of facies following a Maastrichtian–Paleocene sea level fall. Enhanced subsidence on the outer shelf during the Eocene created a forced transgression with carbonate mudstonesiltstone deposition. A highstand during the Oligocene– Early Miocene formed the distinctive prograding carbonate shelf recognised throughout the North West Shelf.A Middle Neogene Supersequence (late Early Miocene– Early Pliocene) is identified by an erosive base and the development of a thin lowstand fan on the outer shelf. The supersequence is largely characterised by backstepping reefs following a Middle Miocene transgression. A Late Miocene eustatic stillstand restricted reef development to the inner shelf, generating coarsegrained carbonate progrades from highstand-shedding. The final Pliocene Supersequence (Pliocene–Recent) was initiated by a eustatic fall during the Early Pliocene and was followed by the development of a transgressive, aggrading shelf.
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Farouk, Sherif, Abdelmohsen Ziko, Shehtta A. Eweda, and Ali E. Said. "Subsurface Miocene sequence stratigraphic framework in the Nile Delta, Egypt." Journal of African Earth Sciences 91 (March 2014): 89–109. http://dx.doi.org/10.1016/j.jafrearsci.2013.12.010.
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Budd, Ann F., Thomas A. Stemann, and Kenneth G. Johnson. "Stratigraphic distributions of genera and species of Neogene to Recent Caribbean reef corals." Journal of Paleontology 68, no. 5 (September 1994): 951–77. http://dx.doi.org/10.1017/s0022336000026585.
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To document evolutionary patterns in late Cenozoic Caribbean reef corals, we compiled composite stratigraphic ranges of 49 genera and 175 species using Neogene occurrences in the Cibao Valley sequence of the northern Dominican Republic and faunal lists for 24 Miocene to Recent sites across the Caribbean region. This new compilation benefits in particular from increased sampling at late Miocene to early Pleistocene sites and from increased resolution and greater taxonomic consistency provided by the use of morphometric procedures in species recognition.Preliminary examination and quantitative analysis of origination and extinction patterns suggest that a major episode of turnover took place between 4 and 1 Ma during Plio-Pleistocene time. During the episode, extinctions were approximately simultaneous in species of all reef-building families, except the Mussidae. Most strongly affected were the Pocilloporidae (Stylophora and Pocillopora), Agariciidae (Pavona and Gardineroseris), and free-living members of the Faviidae and Meandrinidae. At the genus level, mono- and paucispecific as well as more speciose genera became regionally extinct. Many of the extinct genera live today in the Indo-Pacific region, and some are important components of modern eastern Pacific reefs. Global extinctions were concentrated in free-living genera. During the turnover episode, no new genera or higher taxa arose. Instead, new species originated within the surviving Caribbean genera at approximately the same time as the extinctions, including many dominant modern Caribbean reef-building corals (e.g., Acropora palmata and the Montastraea annularis complex).Excluding this episode, the taxonomic composition of the Caribbean reef-coral fauna remained relatively unchanged during the Neogene. Minor exceptions include: 1) high originations in the Agariciidae and free-living corals during late Miocene time; and 2) regional or global extinctions of several important Oligocene Caribbean reef builders during early to middle Miocene time.
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Nyborg, Torrey, Alessandro Garassino, Brant Nyborg, and Francisco J. Vega. "A new cyclodorippid crab, Berglundus bretoni n. gen., n. sp. (Decapoda, Cyclodorippidae) from the Notheastern Pacific, USA." Boletín de la Sociedad Geológica Mexicana 73, no. 3 (December 1, 2021): A301220. http://dx.doi.org/10.18268/bsgm2021v73n3a301220.
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A new cyclodorippid crab, Berglundus bretoni n. gen., n. sp. (Cyclodorippidae Ortmann, 1892) from the Astoria Formation (early to middle Miocene) of Washington State is herein described. It represents the fourth genus of cyclodorippids in North America, keeping the stratigraphic range and the palaeogeographic distribution of the Cyclodorippidae unchanged.
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Zosymovych, V. Yu. "THE NOVI PETRIVTSI REGIONAL STAGE OF THE MIOCENE OF THE NORTHERN UKRAINE." Geological Journal, no. 4 (December 28, 2021): 3–16. http://dx.doi.org/10.30836/igs.1025-6814.2021.4.238658.
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Description of the Novi Petrivtsi Regional Stage of the Miocene of the Stratigraphic Scheme of the Neogene deposits of the Northern Ukraine is given. The Novi Petrivtsi Regional Stage is the first, oldest regional subdivision of this scheme. It corresponds to the Miocene part of the “Poltava stage” of the stratigraphic scheme of the end of XIX century of Lower Tertiary sediments of South Russia by N.A. Sokolov. The Novi Petrivtsi Regional Stage includes the Novi Petrivtsi Formation of the Dnipro-Donets Depression and Ukrainian Shield, the Chasov-Yar Strata, the Strata of clayey sticky sands, the Strata of quartz-siliceous pellites and sandstones of the western and south-western outskirts of Donets basin, lignite deposits and the Strata of dark gray clays of the Novo-Dmytrivka funnel sink. The Novi Petrivtsi Regional Stage reflects the step of the Miocene Sub-Paratethys history connecting with the formation of freshwater megalake within the Northern Ukraine paleosedimentological province after the regression of the last Paleogene sea basin (the late Oligocene, the Sivash time). The Novi Petrivtsi deposits together with the Mottled clays Strata make up the only sedimentation cycle known as the great lakes stage of the Eastern European Platform in the Miocene. Information on fresh-water mollusks, palynology and sporadic foraminifera of the Novi Petrivtsi Regional Stage of the Northern Ukraine is provided. The Novi Petrivtsi Regional Stage of the Northern UKraine is correlated with the Caucasian — Konkian regional stages of the Eastern Paratethys and dated Aquitanian — early Serravallian.
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Fifariz, Reynaldy, Xavier Janson, Charles Kerans, and Benyamin Sapiie. "Carbonate-shelf evolution during the Oligocene to early Miocene: insights from shelf architecture, lithofacies, and depositional models of the Kujung Formation, offshore East Java, Indonesia." Journal of Sedimentary Research 90, no. 8 (August 19, 2020): 796–820. http://dx.doi.org/10.2110/jsr.2020.42.
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ABSTRACT Oligocene–Miocene carbonates are prolific hydrocarbon reservoirs in Southeast Asia. Extensive subsurface data for this stratigraphic section has become available through exploration and production activities. A carbonate shelf in the study area showed an evolution in shelf architecture and lithofacies during this period. Despite the economic importance, complexity, and data availability, there have been few published studies on a comprehensive description and interpretation of carbonate-shelf evolution in the region. We utilized data from nineteen wells and 1,300 km2 of 3D seismic data from offshore East Java to study the Oligocene–Miocene Kujung Formation. An average of 700 m stratigraphic sections from this formation were analyzed. This interval spans 13.5 million years (My) from the Rupelian, Chattian, through Aquitanian constrained by numerical ages from 87Sr/86Sr. The Kujung Formation is subdivided into the Rupelian–Chattian mixed-siliciclastic–carbonate shelf (MSCS) and the Aquitanian carbonate-buildups shelf (CBS) based on shelf architecture and lithofacies. The boundary between the MSCS and CBS is interpreted to be near the Oligocene–Miocene boundary at 23 Ma. Accumulation rates in the CBS are up to three times greater than that of the MSCS. We propose new depositional models for the Kujung Formation, which was used to discuss the dominant controls on shelf evolution. This study suggests that although climate played a role in dictating environmental conditions during the Oligocene–Miocene, the dominant factors controlling carbonate-shelf evolution in the study area appear to have been antecedent topography, routing of siliciclastic sediment, and patterns of sea-level fluctuation.
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Johns, Marjorie J., Julie A. Trotter, Clio J. M. Bonnett, and Christopher R. Barnes. "Neogene strontium isotope stratigraphy, foraminifer biostratigraphy, and lithostratigraphy from offshore wells, Queen Charlotte Basin, British Columbia, Canada." Canadian Journal of Earth Sciences 52, no. 9 (September 2015): 795–822. http://dx.doi.org/10.1139/cjes-2014-0159.
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Strontium isotope ages of foraminifers from Early Miocene to Late Pliocene (Neogene) sequences (21.2–3.4 Ma) are reported for the first time from the Queen Charlotte Basin (QCB) in Queen Charlotte Sound, offshore British Columbia. These ages, together with a revised foraminifer biostratigraphy and log data from two offshore wells, provide a high-resolution chronostratigraphy for the southern part of the QCB. The data show thick 1717–2636 m Miocene sequences overlain by much thinner Pliocene and younger units (<240 m). Assessments of foraminifer biofacies indicate common transported neritic and shelf faunas into slope or bathyal environments where changes in basin water depths indicate significant deformation and erosion. Additional stratigraphic information for six offshore wells in Hecate Strait show the common occurrence of amorphous carbonates in the upper sections of the penetrated basin successions. Amorphous carbonates and coals are less common in the Harlequin D-86 and Osprey D-36 wells of Queen Charlotte Sound. Coals are especially common to abundant in the sedimentary sections penetrated by the Hecate Strait wells and are potential sources of seep fluids and gases. The occurrences of glassy-textured coals, zeolite-like minerals, recrystallized foraminifers, and inverted stratigraphic units in the basal parts of Miocene sub-basins indicate heating, deformation or slumping, and upward mobilization of fluids or gases after the Early Miocene. Results support syn-rift and post-rift depositional and deformational phases. Comparisons between the different geological processes and events in the Queen Charlotte and Tofino basins reveal details of the complex evolution of these Cenozoic basins, plate margins, and ridge junctions.
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Madon, Mazlan, and John Jong. "The Structural-Stratigraphic Framework And Petroleum Systems Of The Sandakan Basin, Offshore East Sabah, Malaysia." Bulletin of the Geological Society of Malaysia 74, no. 1 (November 30, 2022): 135–60. http://dx.doi.org/10.7186/bgsm74202209.
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Decades of exploration activities in the Sandakan Basin offshore eastern Sabah, Malaysia, since the 1970s have yet to yield commercial hydrocarbon discoveries. Of the nineteen wells that have been drilled in the basin up to 2015, only five are classified as discoveries, all made between 1970 and 1995. There are essentially two main proven play types: (1) Early to Middle Miocene “Segama play”, in which the reservoir targets are the Tanjong Formation equivalents within the Segama Group, which were deposited as part of the synrift sequence. (2) Middle to Late Miocene “Sebahat play” in which the reservoirs belong to the Sebahat Formation, characterised by prograding deltaic shoreface and shelf sequences, advancing eastwards and southwards from an uplifting hinterland in central and northern Sabah. The best reservoir facies are shoreface sands, which have porosities greater than 20%, particularly at depths shallower than ~2000 m. Although the generative source rocks have not been penetrated, geochemical data indicate that they are present at depths greater than 3200 m. The source rocks are characterised by predominantly Type III and Types II/III organic matter, which are typical of deltaic settings. The data indicate that hydrocarbons were generated by source rocks with a maturity range of 0.7 – 0.8% vitrinite reflectance (Ro). The Sandakan Basin was affected by several compressional deformation events which are expressed as major erosional unconformities; most significantly, the Middle Miocene (“D2 event”, 13.0 Ma) and Late Miocene (“D3 event”, 8.6 Ma). The unconformities were the result of compression and faulting which, while being responsible for trap formation, may also pose significant risk to trap integrity and preservation. Modelling results indicate that hydrocarbon generation and migration took place during Late Miocene–Early Pliocene and continues today. The basin’s prospectivity, therefore, critically depends on the delicate interplay between the timing of trap formation and hydrocarbon migration. Understanding these processes requires detailed understanding of the structural evolution and petroleum systems of the basin.
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Winter, Chris J., and Paul N. Pearson. "Coiling directions in some Miocene planktonic Foraminifera." Journal of Micropalaeontology 20, no. 1 (July 1, 2001): 29–30. http://dx.doi.org/10.1144/jm.20.1.29.
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Abstract. We have measured the coiling directions of approximately 14 000 Miocene planktonic Foraminifera shells belonging to three lineages (Dentoglobigerina altispira, Paragloborotalia mayeri and Fohsella spp.) from sites in the Pacific (ODP Site 871) and Atlantic (ODP Site 925) oceans. Stratigraphic patterns in the preferred direction of coiling of these forms are assessed and their potential utility for biostratigraphic correlation is discussed. We find that all three lineages show a transition from approximately random coiling (although with a slight discernible sinistral bias in D. altispira) to sinistral predominance in both oceans, although the timing and pattern of change is different in each case.
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Radwański, Andrzej, Marcin Górka, and Anna Wysocka. "Badenian (Middle Miocene) echinoids and starfish from western Ukraine, and their biogeographic and stratigraphic significance." Acta Geologica Polonica 64, no. 2 (June 1, 2014): 224–64. http://dx.doi.org/10.2478/agp-2014-0012.
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Abstract Echinoderms from the Badenian (Middle Miocene) of the Fore-Carpathian Basin of western Ukraine are facies restricted. The Mykolaiv Beds, stratigraphically older, yielded the starfish Astropecten forbesi (complete skeletons), two genera of sand dollars (Parascutella, Parmulechinus), and numerous other echinoids of the genera Psammechinus , Echinocyamus, Spatangus, Hemipatagus, Echinocardium, Clypeaster, Echinolampas, and Conolampas. The stratigraphically younger, calcareous Ternopil Beds yielded Eucidaris (complete coronae, isolated spines), Arbacina , Brissus, and Rhabdobrissus. Sixteen species of echinoids are distinguished and/or commented. A new brissid, Rhabdobrissus tarnopolensis sp. nov., is established. A mass occurrence of some species (Psammechinus dubius and Hemipatagus ocellatus) contrasts with that of mass aggregations (sand dollars and Echinocardium leopolitanum) by dynamic events in selected layers of proximal tempestites. Of special note is the occurrence of very small specimens, interpreted as juveniles (‘babies’) having been swept out of their restricted biotopes (‘nurseries’). Some species hitherto regarded as of Early Miocene age, and the problem of their persistence beyond the Fore-Carpathian Basin and/or migration into that basin during the Middle Miocene transgression are discussed.
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Karim, Kamal H., Hiyam Daoud, Rzger A. Abdula, and Arkan O. Sharezwri. "Occurrence And Relationship Of The Aqra, Bekhme And Govanda Formations In The Soran (Rawanduz) Area, Kurdistan Region, Northeastern Iraq." Bulletin of the Geological Society of Malaysia 73, no. 1 (May 23, 2022): 67–77. http://dx.doi.org/10.7186/bgsm73202206.
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The present study focuses on the presentation of field and laboratory evidences for the first record of the Aqra Formation (Maastrichtian) outcrop at the top of the Tanjero Formation in the Soran area, Erbil Governorate. The previous studies indicated its outcrops as Middle Miocene Govanda Formation between Merga Red Bed Series and Tanjero Formation. The present study discusses relations of this outcrop with Govanda and Bekhme formations in the Sulaimani and Duhok governorates in terms of environment and tectonics. In the Soran area, the formation has variable thickness ranging between 2-160 m and underlies either Red Bed Series or Govanda Formation (Middle Miocene). The study documented many stratigraphic and paleontological evidences to prove occurrence of the Aqra Formation in the area. Additionally, we discussed the significance of its occurrence in detail by which many tectonic and stratigraphic issues of the area are unlocked. One of the issues is occurrence of Tanjero Formation between the Aqra and Bekhme formations and it separates the two formations in two different age ranges and tectonic episodes. Another issue is the documentation of the occurrence of the Aqra Formation inside the Thrust Zone by which the distribution of the formation is extendable beyond Main Zagros Thrust Fault. The study includes a detailed stratigraphic column and tectonic model of the formation to show the coastal area, patchy reef, and shelf environment of the Aqra Formation.