Статті в журналах: "Pleistocene sea level changes"

1

Cosentino, Domenico, Paola Cipollari, Letizia Di Bella, Alessandra Esposito, Costanza Faranda, Guido Giordano, Elsa Gliozzi, et al. "Tectonics, sea-level changes and palaeoenvironments in the early Pleistocene of Rome (Italy)." Quaternary Research 72, no. 1 (July 2009): 143–55. http://dx.doi.org/10.1016/j.yqres.2009.03.003.

Повний текст джерела

Анотація:

AbstractThe historical site of the Monte Mario lower Pleistocene succession (Rome, Italy) is an important marker of the Pliocene/Pleistocene boundary. Recently, the Monte Mario site was excavated and restudied. A spectacular angular unconformity characterizes the contact between the Monte Vaticano and the Monte Mario formations, which marks the Pliocene/Pleistocene boundary. Biostratigraphical analyses carried out on ostracod, foraminifer, and calcareous nannofossil assemblages indicate an Early Pliocene age (topmost Zanclean, 3.81–3.70 Ma) for the underlying Monte Vaticano Formation, whereas the Monte Mario Formation has been dated as early Pleistocene (Santernian, 1.66–1.59 Ma). Palaeomagnetic analyses point to C2Ar and C1r2r polarity chrons for the Monte Vaticano and the Monte Mario formations, respectively. The Monte Mario Formation consists of two obliquity-forced depositional sequences (MM1 and MM2) characterized by transgressive systems tracts of littoral marine environments at depths, respectively, of 40–80 m and 15–20 m. The data obtained from foraminifer and ostracod assemblages allow us to reconstruct early Pleistocene relative sea-level changes near Rome. At the Plio/Pleistocene transition, a relative sea-level drop of at least 260 m occurred, as a result of both tectonic uplift of the central Tyrrhenian margin and glacio-eustatic changes linked to early Pleistocene glaciation (Marine Isotope Stage 58).

Стилі APA, Harvard, Vancouver, ISO та ін.

2

Karin, Benjamin R., Indraneil Das, Todd R. Jackman, and Aaron M. Bauer. "Ancient divergence time estimates inEutropis rugiferasupport the existence of Pleistocene barriers on the exposed Sunda Shelf." PeerJ 5 (October 27, 2017): e3762. http://dx.doi.org/10.7717/peerj.3762.

Повний текст джерела

Анотація:

Episodic sea level changes that repeatedly exposed and inundated the Sunda Shelf characterize the Pleistocene. Available evidence points to a more xeric central Sunda Shelf during periods of low sea levels, and despite the broad land connections that persisted during this time, some organisms are assumed to have faced barriers to dispersal between land-masses on the Sunda Shelf.Eutropis rugiferais a secretive, forest adapted scincid lizard that ranges across the Sunda Shelf. In this study, we sequenced one mitochondrial (ND2) and four nuclear (BRCA1,BRCA2,RAG1, andMC1R) markers and generated a time-calibrated phylogeny in BEAST to test whether divergence times between Sundaic populations ofE. rugiferaoccurred during Pleistocene sea-level changes, or if they predate the Pleistocene. We find thatE. rugiferashows pre-Pleistocene divergences between populations on different Sundaic land-masses. The earliest divergence withinE. rugiferaseparates the Philippine samples from the Sundaic samples approximately 16 Ma; the Philippine populations thus cannot be considered conspecific with Sundaic congeners. Sundaic populations diverged approximately 6 Ma, and populations within Borneo from Sabah and Sarawak separated approximately 4.5 Ma in the early Pliocene, followed by further cladogenesis in Sarawak through the Pleistocene. Divergence of peninsular Malaysian populations from the Mentawai Archipelago occurred approximately 5 Ma. Separation among island populations from the Mentawai Archipelago likely dates to the Pliocene/Pleistocene boundary approximately 3.5 Ma, and our samples from peninsular Malaysia appear to coalesce in the middle Pleistocene, about 1 Ma. Coupled with the monophyly of these populations, these divergence times suggest that despite consistent land-connections between these regions throughout the PleistoceneE. rugiferastill faced barriers to dispersal, which may be a result of environmental shifts that accompanied the sea-level changes.

Стилі APA, Harvard, Vancouver, ISO та ін.

3

Spratt, Rachel M., and Lorraine E. Lisiecki. "A Late Pleistocene sea level stack." Climate of the Past 12, no. 4 (April 26, 2016): 1079–92. http://dx.doi.org/10.5194/cp-12-1079-2016.

Повний текст джерела

Анотація:

Abstract. Late Pleistocene sea level has been reconstructed from ocean sediment core data using a wide variety of proxies and models. However, the accuracy of individual reconstructions is limited by measurement error, local variations in salinity and temperature, and assumptions particular to each technique. Here we present a sea level stack (average) which increases the signal-to-noise ratio of individual reconstructions. Specifically, we perform principal component analysis (PCA) on seven records from 0 to 430 ka and five records from 0 to 798 ka. The first principal component, which we use as the stack, describes ∼ 80 % of the variance in the data and is similar using either five or seven records. After scaling the stack based on Holocene and Last Glacial Maximum (LGM) sea level estimates, the stack agrees to within 5 m with isostatically adjusted coral sea level estimates for Marine Isotope Stages 5e and 11 (125 and 400 ka, respectively). Bootstrapping and random sampling yield mean uncertainty estimates of 9–12 m (1σ) for the scaled stack. Sea level change accounts for about 45 % of the total orbital-band variance in benthic δ18O, compared to a 65 % contribution during the LGM-to-Holocene transition. Additionally, the second and third principal components of our analyses reflect differences between proxy records associated with spatial variations in the δ18O of seawater.

Стилі APA, Harvard, Vancouver, ISO та ін.

4

Spratt, R. M., and L. E. Lisiecki. "A Late Pleistocene sea level stack." Climate of the Past Discussions 11, no. 4 (August 13, 2015): 3699–728. http://dx.doi.org/10.5194/cpd-11-3699-2015.

Повний текст джерела

Анотація:

Abstract. Late Pleistocene sea level has been reconstructed from ocean sediment core data using a wide variety of proxies and models. However, the accuracy of individual reconstructions is limited by measurement error, local variations in salinity and temperature, and assumptions particular to each technique. Here we present a sea level stack (average) which increases the signal-to-noise ratio of individual reconstructions. Specifically, we perform principal component analysis (PCA) on seven records from 0–430 ka and five records from 0–798 ka. The first principal component, which we use as the stack, describes ~80 % of the variance in the data and is similar using either five or seven records. After scaling the stack based on Holocene and Last Glacial Maximum (LGM) sea level estimates, the stack agrees to within 5 m with isostatically adjusted coral sea level estimates for Marine Isotope Stages 5e and 11 (125 and 400 ka, respectively). When we compare the sea level stack with the δ18O of benthic foraminifera, we find that sea level change accounts for about ~40 % of the total orbital-band variance in benthic δ18O, compared to a 65 % contribution during the LGM-to-Holocene transition. Additionally, the second and third principal components of our analyses reflect differences between proxy records associated with spatial variations in the δ18O of seawater.

Стилі APA, Harvard, Vancouver, ISO та ін.

5

Reeder-Myers, Leslie, Jon M. Erlandson, Daniel R. Muhs, and Torben C. Rick. "Sea level, paleogeography, and archeology on California's Northern Channel islands." Quaternary Research 83, no. 2 (March 2015): 263–72. http://dx.doi.org/10.1016/j.yqres.2015.01.002.

Повний текст джерела

Анотація:

Sea-level rise during the late Pleistocene and early Holocene inundated nearshore areas in many parts of the world, producing drastic changes in local ecosystems and obscuring significant portions of the archeological record. Although global forces are at play, the effects of sea-level rise are highly localized due to variability in glacial isostatic adjustment (GIA) effects. Interpretations of coastal paleoecology and archeology require reliable estimates of ancient shorelines that account for GIA effects. Here we build on previous models for California's Northern Channel Islands, producing more accurate late Pleistocene and Holocene paleogeographic reconstructions adjusted for regional GIA variability. This region has contributed significantly to our understanding of early New World coastal foragers. Sea level that was about 80-85 m lower than present at the time of the first known human occupation brought about a landscape and ecology substantially different than today. During the late Pleistocene, large tracts of coastal lowlands were exposed, while a colder, wetter climate and fluctuating marine conditions interacted with rapidly evolving littoral environments. At the close of the Pleistocene and start of the Holocene, people in coastal California faced shrinking land, intertidal, and subtidal zones, with important implications for resource availability and distribution.

Стилі APA, Harvard, Vancouver, ISO та ін.

6

Kızıldağ, Nilhan, A. Harun Özdas, and Atilla Uluğ. "Late Pleistocene and Holocene Sea Level Changes in the Hisarönü Gulf, Southeast Aegean Sea." Geoarchaeology 27, no. 3 (April 19, 2012): 220–36. http://dx.doi.org/10.1002/gea.21407.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

7

Wang, Liyan, Guangxue Li, Jishang Xu, Yong Liu, Lulu Qiao, Dong Ding, Jichao Yang, Olusegun A. Dada, and Qian Li. "Strata sequence and paleochannel response to tectonic, sea-level, and Asian monsoon variability since the late Pleistocene in the South Yellow Sea." Quaternary Research 92, no. 2 (June 27, 2019): 450–68. http://dx.doi.org/10.1017/qua.2019.29.

Повний текст джерела

Анотація:

AbstractThe continental shelf strata provide information regarding sea-level fluctuation and climate changes in the Quaternary period. A 5831.47-km-long high-resolution seismic profile and borehole core (YS01) were acquired to reconstruct the evolutionary history of the strata in South Yellow Sea (SYS) during the late Pleistocene. The strata recorded three transgression events (HI, HII, and HIII) and three stages of paleochannel development (LI, LII, and LIII). Based on the distribution, thickness, and volume of the strata formed in the three transgressions, we concluded that the scale of the three transgressions during the late Pleistocene was HIII, HI, and HII, in descending order. In addition, our data show that the Yellow River extended to the Yellow Sea Trough during the last glacial maximum. The influence of the tectonic framework on sedimentation in the SYS was completely concealed by sea-level changes and sediment supply in the late Pleistocene (~Marine Isotope Stage 5). Since then, the accommodation space, a crucial prerequisite for sedimentation, has been controlled solely by sea-level changes in the SYS. Furthermore, two “source to sink” models of the neritic shelf in the marine and terrestrial environments were established, including high sea-level and shelf-exposure models.

Стилі APA, Harvard, Vancouver, ISO та ін.

8

Chmal, Henryk. "Pleistocene sea level changes and glacial history of the Hornsund area, Svalbard." Polar Research 5, no. 3 (January 12, 1987): 269–70. http://dx.doi.org/10.3402/polar.v5i3.6883.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

9

CHMAL, HENRYK. "Pleistocene sea level changes and glacial history of the Hornsund area, Svalbard." Polar Research 5, no. 3 (December 1987): 269–70. http://dx.doi.org/10.1111/j.1751-8369.1987.tb00545.x.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

10

Prizomwala, S. P., Gunjan Yadav, Nilesh Bhatt, and Komal Sharma. "Late Pleistocene Relative Sea-Level Changes from Saurashtra, West Coast of India." Current Science 115, no. 12 (December 25, 2018): 2297. http://dx.doi.org/10.18520/cs/v115/i12/2297-2301.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

11

Salomonsen, Inger. "Origin of a deep buried valley system in Pleistocene deposits of the eastern central North Sea." Danmarks Geologiske Undersøgelse Serie C 12 (December 31, 1995): 7–19. http://dx.doi.org/10.34194/seriec.v12.7106.

Повний текст джерела

Анотація:

In the North Sea, the sedimentary development of the late Tertiary and early Quaternary was dominated by deltaic sedimentation in a fast subsiding basin. During the Pleistocene, pronounced climatic changes affected the sedimentation of the area and progradation of the delta systems ceased. The Middle and Upper Pleistocene sedimentary successions consist of alternations of marine and fluvial deposits, partly reworked during glacial periods. Seismic records from the Danish sector of the North Sea reveal numerous deep incisions cut down from various levels of the Middle and Upper Pleistocene successions. These incisions are concluded to form a pattern of buried valleys. Detailed seismic stratigraphic analysis shows the occurrence of various internal unconformities within these buried valleys. It is concluded that the valleys originate from a river system developed in periods of repeated sea-level changes. Pluvial erosion during glacial sea-level lowstand and glacial meltwater action is proposed to have been responsible for the origin of the valley system. Thus, in Middle and Upper Pleistocene glacial periods drainage and associated sediment transport occurred from Northwest and Central European land areas via a presently buried river system in the southeastern North Sea towards a depositional basin north and northwest of the Danish North Sea sector.

Стилі APA, Harvard, Vancouver, ISO та ін.

12

Donders, Timme H., Niels A. G. M. van Helmond, Roel Verreussel, Dirk Munsterman, Johan ten Veen, Robert P. Speijer, Johan W. H. Weijers, et al. "Land–sea coupling of early Pleistocene glacial cycles in the southern North Sea exhibit dominant Northern Hemisphere forcing." Climate of the Past 14, no. 3 (March 23, 2018): 397–411. http://dx.doi.org/10.5194/cp-14-397-2018.

Повний текст джерела

Анотація:

Abstract. We assess the disputed phase relations between forcing and climatic response in the early Pleistocene with a spliced Gelasian (∼2.6–1.8 Ma) multi-proxy record from the southern North Sea basin. The cored sections couple climate evolution on both land and sea during the intensification of Northern Hemisphere glaciation (NHG) in NW Europe, providing the first well-constrained stratigraphic sequence of the classic terrestrial Praetiglian stage. Terrestrial signals were derived from the Eridanos paleoriver, a major fluvial system that contributed a large amount of freshwater to the northeast Atlantic. Due to its latitudinal position, the Eridanos catchment was likely affected by early Pleistocene NHG, leading to intermittent shutdown and reactivation of river flow and sediment transport. Here we apply organic geochemistry, palynology, carbonate isotope geochemistry, and seismostratigraphy to document both vegetation changes in the Eridanos catchment and regional surface water conditions and relate them to early Pleistocene glacial–interglacial cycles and relative sea level changes. Paleomagnetic and palynological data provide a solid integrated timeframe that ties the obliquity cycles, expressed in the borehole geophysical logs, to Marine Isotope Stages (MIS) 103 to 92, independently confirmed by a local benthic oxygen isotope record. Marine and terrestrial palynological and organic geochemical records provide high-resolution reconstructions of relative terrestrial and sea surface temperature (TT and SST), vegetation, relative sea level, and coastal influence. During the prominent cold stages MIS 98 and 96, as well as 94, the record indicates increased non-arboreal vegetation, low SST and TT, and low relative sea level. During the warm stages MIS 99, 97, and 95 we infer increased stratification of the water column together with a higher percentage of arboreal vegetation, high SST, and relative sea level maxima. The early Pleistocene distinct warm–cold alterations are synchronous between land and sea, but lead the relative sea level change by 3000–8000 years. The record provides evidence for a dominantly Northern Hemisphere-driven cooling that leads the glacial buildup and varies on the obliquity timescale. Southward migration of Arctic surface water masses during glacials, indicated by cool-water dinoflagellate cyst assemblages, is furthermore relevant for the discussion on the relation between the intensity of the Atlantic meridional overturning circulation and ice sheet growth.

Стилі APA, Harvard, Vancouver, ISO та ін.

13

Caratini, C., G. Delibrias, and G. Rajagopalan. "Palaeomangroves of Kanara coast, Karnataka, India and their implications on Late Pleistocene sea-level changes." Journal of Palaeosciences 38 (December 31, 1989): 370–78. http://dx.doi.org/10.54991/jop.1989.1672.

Повний текст джерела

Анотація:

Along the Kanara coast, some wells, show an organic clay layer, 1.5 to 7 m thick, between a layer of 2 to 6 m of coarse yellow sand above and white sand and pebbles below. The altitude of this intermediate organic clay formation is more or less at the present mean sea-level. Palynological analyses reveal that this sediment had been deposited within a mangrove environment i.e. at sea-level, while the 14 C datings give ages older than 40,000 years B. P. No proof of vertical movements after the deposit of the intermediate organic clay formation has been put forward up to now. Therefore, it can be accepted that the present elevation of this formation is more or less the same as its original altitude i.e., the present sea-level. Comparison of this altitude with the curves of global sea-level changes indicates that the period of deposition of these organic sediments should be around 125,000 years B.P., during the last Interglacial (Eemian) when the sea-level was ± the same that it is today. The main characteristics of “Eemian” flora were the same as the present. The climatic regime may have been slightly different with the less contrasting season.

Стилі APA, Harvard, Vancouver, ISO та ін.

14

Kazanskiy, A. B. "A Hypothesis for the Sawlike Pattern of World Sea-Level Fluctuations." Quaternary Research 24, no. 3 (November 1985): 285–94. http://dx.doi.org/10.1016/0033-5894(85)90051-1.

Повний текст джерела

Анотація:

A theory of the world's sea-level fluctuations during late Pleistocene time, based on the analysis of the general equation of the mass balance between ocean water and inland water, suggests that the exchange of water masses between the ocean and the land, where at continental glaciation periods water is stored as ice, occurs only as a result of global climatic changes. The tectonic effect is considered insignificant for late Pleistocene time. The proposed theory explains the asymmetric character and the sawlike shape of the curve of the main cycles of sea-level fluctuations. The theory also makes it possible to construct a diagram of sea-level fluctuations from the last glacial maximum to the present time. This diagram is governed by two parameters, the amount of the average “effective” evaporation from the world's ocean surface (evaporation minus rainfall) and the rate of the sea-level rise at the present time. The resulting theoretical curve agrees well with known estimates of sea level within the time span being considered. The comparison of the theoretical curve with these estimates eliminates the apparent discrepancy between data obtained by different methods: measurements of old coastline and the isotopic composition of bottom sediments.

Стилі APA, Harvard, Vancouver, ISO та ін.

15

van der Zee, Jurjan P., Marjolijn J. A. Christianen, Martine Bérubé, Mabel Nava, Sietske van der Wal, Jessica Berkel, Tadzio Bervoets, Melanie Meijer zu Schlochtern, Leontine E. Becking, and Per J. Palsbøll. "Demographic changes in Pleistocene sea turtles were driven by past sea level fluctuations affecting feeding habitat availability." Molecular Ecology 31, no. 4 (December 14, 2021): 1044–56. http://dx.doi.org/10.1111/mec.16302.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

16

Shelley, James J., Stephen E. Swearer, Tim Dempster, Mark Adams, Matthew C. Le Feuvre, Michael P. Hammer, and Peter J. Unmack. "Plio‐Pleistocene sea‐level changes drive speciation of freshwater fishes in north‐western Australia." Journal of Biogeography 47, no. 8 (April 19, 2020): 1727–38. http://dx.doi.org/10.1111/jbi.13856.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

17

Fedorov, P. V. "THE PROBLEM OF CHANGES IN THE LEVEL OF THE BLACK SEA DURING THE PLEISTOCENE." International Geology Review 30, no. 6 (June 1988): 635–41. http://dx.doi.org/10.1080/00206818809466043.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

18

Granja, Helena Maria, and G. Soares Carvalho. "Sea-level changes during the Pleistocene-Holocene in the NW coastal zone of Portugal." Terra Nova 7, no. 1 (January 1995): 60–67. http://dx.doi.org/10.1111/j.1365-3121.1995.tb00668.x.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

19

De Waele, Jo, Ilenia M. D'Angeli, Tomaso Bontognali, Paola Tuccimei, Denis Scholz, Klaus Peter Jochum, Andrea Columbu, et al. "Speleothems in a north Cuban cave register sea-level changes and Pleistocene uplift rates." Earth Surface Processes and Landforms 43, no. 11 (May 22, 2018): 2313–26. http://dx.doi.org/10.1002/esp.4393.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

20

Frigola, J., M. Canals, I. Cacho, A. Moreno, F. J. Sierro, J. A. Flores, S. Berné, et al. "A 500 kyr record of global sea-level oscillations in the Gulf of Lion, Mediterranean Sea: new insights into MIS 3 sea-level variability." Climate of the Past 8, no. 3 (June 22, 2012): 1067–77. http://dx.doi.org/10.5194/cp-8-1067-2012.

Повний текст джерела

Анотація:

Abstract. Borehole PRGL1-4 drilled in the upper slope of the Gulf of Lion provides an exceptional record to investigate the impact of late Pleistocene orbitally-driven glacio-eustatic sea-level oscillations on the sedimentary outbuilding of a river fed continental margin. High-resolution grain-size and geochemical records supported by oxygen isotope chronostratigraphy allow reinterpreting the last 500 ka upper slope seismostratigraphy of the Gulf of Lion. Five main sequences, stacked during the sea-level lowering phases of the last five glacial-interglacial 100-kyr cycles, form the upper stratigraphic outbuilding of the continental margin. The high sensitivity of the grain-size record down the borehole to sea-level oscillations can be explained by the great width of the Gulf of Lion continental shelf. Sea level driven changes in accommodation space over the shelf cyclically modified the depositional mode of the entire margin. PRGL1-4 data also illustrate the imprint of sea-level oscillations at millennial time-scale, as shown for Marine Isotopic Stage 3, and provide unambiguous evidence of relative high sea-levels at the onset of each Dansgaard-Oeschger Greenland warm interstadial. The PRGL1-4 grain-size record represents the first evidence for a one-to-one coupling of millennial time-scale sea-level oscillations associated with each Dansgaard-Oeschger cycle.

Стилі APA, Harvard, Vancouver, ISO та ін.

21

Frigola, J., M. Canals, I. Cacho, A. Moreno, F. J. Sierro, J. A. Flores, S. Berné, et al. "A 500 kyr record of global sea level oscillations in the Gulf of Lion, Mediterranean Sea: new insights into MIS 3 sea level variability." Climate of the Past Discussions 7, no. 6 (December 20, 2011): 4401–28. http://dx.doi.org/10.5194/cpd-7-4401-2011.

Повний текст джерела

Анотація:

Abstract. Borehole PRGL1-4 drilled in the upper slope of the Gulf of Lion provides an exceptional record to investigate the impact of Late Pleistocene orbitally-driven glacio-eustatic sea level oscillations on the sedimentary outbuilding of a river fed continental margin. High-resolution grain-size and geochemical records supported by oxygen isotope chronostratigraphy allow reinterpreting the last 500 ka upper slope seismostratigraphy of the Gulf of Lion which consists of five main sequences stacked during the sea level lowering phases of the last five glacial-interglacial 100-kyr cycles. The high sensitivity to sea level oscillations of the grain-size record along the borehole, favoured by the large width of the Gulf of Lion continental shelf, demonstrates that sea level driven changes in accommodation space over the shelf are able to cyclically modify the depositional mode of the entire margin. PRGL1-4 data also illustrate the imprint of sea level oscillations at millennial scale, as shown for Marine Isotopic Stage 3, and provide unambiguous evidence of relative high sea levels at the onset of each Dansgaard-Oeschger Greenland warm interstadial. The PRGL1-4 grain-size record represents the first evidence ever for a one-to-one coupling of millennial-scale sea level oscillations associated with each Dansgaard-Oeschger cycle.

Стилі APA, Harvard, Vancouver, ISO та ін.

22

Cui, Xiaohui, Shoujun Li, Hua Xu, Zhuo Zhang, Xiuli Zhao, Zongjun Gao, Ning Wei, and Xiangyu Zhang. "Late Quaternary Paleoenvironmental Reconstruction, Using Benthic Foraminifera and Ostracoda, of Marine Sedimentary Beds On the Southern Coast of Laizhou Bay, Bohai Sea, China." Journal of Foraminiferal Research 48, no. 2 (April 20, 2018): 87–99. http://dx.doi.org/10.2113/gsjfr.48.2.87.

Повний текст джерела

Анотація:

Abstract Extensive studies of Quaternary transgressions have been conducted in Bohai Sea, but debates continue regarding the sedimentary evolution and timing of transgressions, especially in the Pleistocene section. Benthic foraminifers and ostracodes from three boreholes (GK138, GK111, GK95) at Laizhou Bay, Bohai Sea, were utilized to interpret the paleoenvironments of deposition and elucidate the coastal response to global sea-level changes since the late Quaternary. Benthic foraminiferal species identified included 32 species from 15 genera; ostracodes included 28 species from 16 genera. Three marine sedimentary beds were recognized based on sedimentary characteristics, down-core changes in environmental proxies (benthic foraminifers and ostracodes), accelerator mass spectrometry (AMS) 14C, and optically stimulated luminescence (OSL) dates. These three beds were interpreted as: marine sedimentary bed 3 (M3), deposited in the late-middle Pleistocene; marine sedimentary bed 2 (M2), deposited during the late Pleistocene; and marine sedimentary bed 1 (M1), deposited during the Holocene. Three microfossil assemblages were identified, all indicating nearshore conditions. Assemblage III indicated a fluvially influenced or paralic environment during a relatively small-scale late-middle Pleistocene transgression that produced bed M3. Assemblage II indicates an intertidal-subtidal environment where bed M2 was deposited during the late Pleistocene transgression. Assemblage I indicates somewhat more marine influence in a subtidal environment where bed M1 was deposited during the Holocene marine transgression.

Стилі APA, Harvard, Vancouver, ISO та ін.

23

Lambeck, Kurt, and Masao Nakada. "Late Pleistocene and Holocene sea-level change along the Australian coast." Global and Planetary Change 3, no. 1-2 (October 1990): 143–76. http://dx.doi.org/10.1016/0921-8181(90)90060-p.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

24

Du, Zhenyong, Tadashi Ishikawa, Hui Liu, Satoshi Kamitani, Osamu Tadauchi, Wanzhi Cai, and Hu Li. "Phylogeography of the Assassin Bug Sphedanolestes impressicollis in East Asia Inferred From Mitochondrial and Nuclear Gene Sequences." International Journal of Molecular Sciences 20, no. 5 (March 12, 2019): 1234. http://dx.doi.org/10.3390/ijms20051234.

Повний текст джерела

Анотація:

The assassin bug, Sphedanolestes impressicollis (Hemiptera: Reduviidae), is widely distributed in East Asia. It is an ideal model for evaluating the effects of climatic fluctuation and geographical events on the distribution patterns of East Asian reduviids. Here, we used two mitochondrial genes and one nuclear gene to investigate the phylogeographic pattern of the assassin bug based on comprehensive sampling in China, Japan, South Korea, Vietnam, and Laos. High levels of genetic differentiation were detected among the geographic populations classified into the northern and southern groups. A significant correlation was detected between genetic and geographical distances. The East China Sea land bridge served as a “dispersal corridor” during Pleistocene glaciation. The estimated divergence time indicated that the northern group may have separated from the eastern Chinese populations when the sea level rapidly rose during the “Ryukyu Coral Sea Stage” and the East China Sea land bridge was completely submerged. Demographic history and ecological niche modeling suggested that appropriate climatic conditions may have accounted for the rapid spread across the Korean Peninsula and Japan during the late Pleistocene. Our study underscores the pivotal roles of the Pleistocene sea level changes and climatic fluctuations in determining the distribution patterns of East Asian reduviids.

Стилі APA, Harvard, Vancouver, ISO та ін.

25

Aiello, Gemma. "Quaternary Lowstand Prograding Wedges of the Salento Continental Shelf (Southern Adriatic Sea, Italy): Architectural Stacking Patterns and the Control of Glacio-Eustatic Sea Level Fluctuations and Foreland Tectonic Uplift." Geosciences 13, no. 1 (December 22, 2022): 4. http://dx.doi.org/10.3390/geosciences13010004.

Повний текст джерела

Анотація:

The performance of both the tectonic uplift and of the 4th-order glacial eustatic sea level fluctuations in controlling the stratigraphic architecture of Quaternary lowstand prograding wedges of the Salento continental shelf (Southern Adriatic sea, Italy) during a time interval spanning from the Middle Pleistocene to the Holocene has been pointed out through the interpretation of high-resolution seismic reflection profiles and their correlation to the curves of the isotopic stratigraphy. Three main transgressive surfaces of erosion (RS1, RS2 and RS3) punctuate the stratigraphic architecture of the Salento continental shelf, separating Quaternary lowstand prograding wedges between them. All along the Middle Pleistocene, increasing the tectonic uplift of the Puglia offshore, combining with 4th-order glacio-eustatic variations, have dealt with the pattern of a broad forced regression prograding wedge, favoring a platform progradation of approximately 15 km. The architectural stacking patterns of the overlying Late Pleistocene and Holocene prograding wedges are controlled by 4th-order glacio-eustatic sea level changes, allowing for the formation of incomplete depositional sequences. In this period, the eustatic signature overcomes the tectonic mark, implying a decline in the uplift of the Apulian foreland in the course of the final 250 ky.

Стилі APA, Harvard, Vancouver, ISO та ін.

26

Wong, Th E., R. de Kramer, P. L. de Boer, C. Langereis, and J. Sew-A-Tjon. "The influence of sea-level changes on tropical coastal lowlands; the Pleistocene Coropina Formation, Suriname." Sedimentary Geology 216, no. 3-4 (April 2009): 125–37. http://dx.doi.org/10.1016/j.sedgeo.2009.02.003.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

27

Emslie, Steven D. "Avian Community, Climate, and Sea-Level Changes in the Plio-Pleistocene of the Florida Peninsula." Ornithological Monographs, no. 50 (January 1998): 1–113. http://dx.doi.org/10.2307/40166707.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

28

Gabriel, Gerald, Dietrich Ellwanger, Christian Hoselmann, and Michael Weidenfeller. "Preface: The Heidelberg Basin Drilling Project." E&G Quaternary Science Journal 57, no. 3/4 (April 1, 2009): 253–69. http://dx.doi.org/10.3285/eg.57.3-4.00.

Повний текст джерела

Анотація:

Abstract. Since Late Pliocene / Early Pleistocene, the River Rhine, as one of the largest European rivers, has acted as the only drainage system that connected the Alps with Northern Europe, especially the North Sea. Along its course from the Alps to the English Channel the river passes several geomorphological and geological units, of which the Upper Rhine Graben acts as the major sediment trap. Whereas the potential of sediment preservation of the alpine foreland basins is low due to the high dynamics of the system, and the area of deposition close to the North Sea was significantly affected several times by Pleistocene sea level changes, the ongoing subsidence of the Upper Rhine Graben offers a unique potential for a continuous sediment accumulation and preservation.

Стилі APA, Harvard, Vancouver, ISO та ін.

29

Esin, Nikolay V., Nikolay I. Esin, Igor S. Podymov, Anna V. Lifanchuk, and Irina V. Melnikova. "Formation mechanisms of the Caspian transgressive seas in the Pleistocene." Hydrosphere Еcology (Экология гидросферы), no. 1(3) (2019): 13–23. http://dx.doi.org/10.33624/2587-9367-2019-1(3)-13-23.

Повний текст джерела

Анотація:

The basis of the theory of evolution of transgressive the Akchagyl Sea is based on the hypothesis that the transgression was created by water coming from an as yet unidentified ocean. This causes some doubt due to the fact that in the Akchagyl time the ocean level was about 100 m below sea level. The article calculates changes in salinity in the sea. A comparison of the results of calculations with geological data shows that in reality the salinity of the water entering the sea was 2–3 orders of magnitude lower than the salinity of ocean water. Theoretically, only in 1000 years, the salinity of seawater was supposed to increase to 120‰, and geological studies showed that during the whole time of transgression the salinity of the water was not higher than 25‰. This indicates that during the transgression the water came not from the ocean, but from melting glaciers, i.e. water theoretically could not flow upwards, and it never really flowed upwards.

Стилі APA, Harvard, Vancouver, ISO та ін.

30

Berends, Constantijn J., Bas de Boer, and Roderik S. W. van de Wal. "Reconstructing the evolution of ice sheets, sea level, and atmospheric CO<sub>2</sub> during the past 3.6 million years." Climate of the Past 17, no. 1 (February 1, 2021): 361–77. http://dx.doi.org/10.5194/cp-17-361-2021.

Повний текст джерела

Анотація:

Abstract. Understanding the evolution of, and the interactions between, ice sheets and the global climate over geological timescales is important for being able to project their future evolution. However, direct observational evidence of past CO2 concentrations, and the implied radiative forcing, only exists for the past 800 000 years. Records of benthic δ18O date back millions of years but contain signals from both land ice volume and ocean temperature. In recent years, inverse forward modelling has been developed as a method to disentangle these two signals, resulting in mutually consistent reconstructions of ice volume, temperature, and CO2. We use this approach to force a hybrid ice-sheet–climate model with a benthic δ18O stack, reconstructing the evolution of the ice sheets, global mean sea level, and atmospheric CO2 during the late Pliocene and the Pleistocene, from 3.6 million years (Myr) ago to the present day. During the warmer-than-present climates of the late Pliocene, reconstructed CO2 varies widely, from 320–440 ppmv for warm periods to 235–250 ppmv for the early glacial excursion ∼3.3 million years ago. Sea level is relatively stable during this period, with maxima of 6–14 m and minima of 12–26 m during glacial episodes. Both CO2 and sea level are within the wide ranges of values covered by available proxy data for this period. Our results for the Pleistocene agree well with the ice-core CO2 record, as well as with different available sea-level proxy data. For the Early Pleistocene, 2.6–1.2 Myr ago, we simulate 40 kyr glacial cycles, with interglacial CO2 decreasing from 280–300 ppmv at the beginning of the Pleistocene to 250–280 ppmv just before the Mid-Pleistocene Transition (MPT). Peak glacial CO2 decreases from 220–250 to 205–225 ppmv during this period. After the MPT, when the glacial cycles change from 40 to 80 120 kyr cyclicity, the glacial–interglacial contrast increases, with interglacial CO2 varying between 250–320 ppmv and peak glacial values decreasing to 170–210 ppmv.

Стилі APA, Harvard, Vancouver, ISO та ін.

31

Steadman, David W., Nancy A. Albury, Brian Kakuk, Jim I. Mead, J. Angel Soto-Centeno, Hayley M. Singleton, and Janet Franklin. "Vertebrate community on an ice-age Caribbean island." Proceedings of the National Academy of Sciences 112, no. 44 (October 19, 2015): E5963—E5971. http://dx.doi.org/10.1073/pnas.1516490112.

Повний текст джерела

Анотація:

We report 95 vertebrate taxa (13 fishes, 11 reptiles, 63 birds, 8 mammals) from late Pleistocene bone deposits in Sawmill Sink, Abaco, The Bahamas. The >5,000 fossils were recovered by scuba divers on ledges at depths of 27–35 m below sea level. Of the 95 species, 39 (41%) no longer occur on Abaco (4 reptiles, 31 birds, 4 mammals). We estimate that 17 of the 39 losses (all of them birds) are linked to changes during the Pleistocene–Holocene Transition (PHT) (∼15–9 ka) in climate (becoming more warm and moist), habitat (expansion of broadleaf forest at the expense of pine woodland), sea level (rising from −80 m to nearly modern levels), and island area (receding from ∼17,000 km2 to 1,214 km2). The remaining 22 losses likely are related to the presence of humans on Abaco for the past 1,000 y. Thus, the late Holocene arrival of people probably depleted more populations than the dramatic physical and biological changes associated with the PHT.

Стилі APA, Harvard, Vancouver, ISO та ін.

32

Hodgson, Douglas A., Robert B. Taylor, and John G. Fyles. "Late Quaternary Sea Level Changes on Brock and Prince Patrick Islands, Western Canadian Arctic Archipelago." Géographie physique et Quaternaire 48, no. 1 (November 23, 2007): 69–84. http://dx.doi.org/10.7202/032973ar.

Повний текст джерела

Анотація:

ABSTRACT Emerged shorelines are few and poorly defined on Prince Patrick and Brock islands. The sparse radiocarbon dates show emergence of only 10 m through the Holocene on the Arctic Ocean coast, increasing to 20 m 100 km to the east. Hence, from Brock Island, representative of westernmost coasts, the sea level curve since the latest Pleistocene has a very low gradient, whereas on eastern Prince Patrick Island the curve takes the more typical exponential form. A decline in isobases towards the west is thus registered. Drowned estuaries, breached lakes, and coastal barriers, particularly in southwest Prince Patrick Island, suggest that the sea is now transgressing at a rate that decreases towards the north end of the island, hence there is also a component of tilt to the south. Delevelling is assumed to result from undefined ice loads, but may have a tectonic component. The sole prominent raised marine deposit is a ridge probably built in a period of more mobile sea ice, possibly at a time of stable or slightly rising sea level in the middle or early Holocene. It winds discontinuously along several hundred of kilometres of the shores of the Arctic Ocean and connecting channels, declining to the south.

Стилі APA, Harvard, Vancouver, ISO та ін.

33

Seitz, Carina, María I. Vélez, and Gerardo M. E. Perillo. "Cenozoic geologic evolution of the lower Colorado River Basin, Northern Patagonia, Argentina." Andean Geology 46, no. 1 (September 28, 2018): 131. http://dx.doi.org/10.5027/andgeov46n1-3060.

Повний текст джерела

Анотація:

Climatic changes and eustatic sea levels have been assumed to be the most important controllers of the Colorado River alluvial fan in northern Patagonia. Although the alluvial fan occurs in a region considered tectonically stable, there are pieces of evidence that the Miocene Andean orogeny has reactivated inherited structures, with subsequent geomorphological changes that date back to the Pleistocene. Besides, the clear evidence of neotectonism in the region and their effects on the evolution of this fan, it has not been studied in detail yet. In this study, we map and analyze six sections outcropping in different terraces of the alluvial fan with the primary aim of disentangling the role of tectonism, climate and eustatic changes on the evolution of the alluvial fan. This study is part of a bigger project aimed to understand the origin of the shallow lakes occurring in northern Patagonia. Our results indicate that the alluvial fan of the Colorado River was established in the area around the Middle Pleistocene. Evidence of deformations in Miocene to Pleistocene units indicates significant neotectonism during the Upper Pleistocene. By the Pleistocene-Holocene transition, tectonism produced incision generating a set of terraces. After this time, an important climate change from semiarid to arid favored the calcretization of some terraces. By the Pleistocene-Middle Holocene, the terraces were covered by ancient eolian sediment accumulated during dry conditions. By the Middle Holocene, a broad alluvial fan developed in the region under a warmer and more humid climate generating the Alluvial Colorado River-III deposit at the T3 terrace. In the late Holocene, aggradation process was favored by a high sea level and temperate-arid climate, producing T4 terrace. At the same time, this climate condition favored the local deflation-sedimentation processes that resulted in the deposition of modern eolian deposits (mE) over the T3 terrace. The depressions generated by the deflation were, later on, occupied by shallow lakes when the climate turn more humid. Subsequently, during regressive sea level condition, ca. 2000 years BP, the T4 terrace was partially eroded and the modern alluvial plain formed.

Стилі APA, Harvard, Vancouver, ISO та ін.

34

Wright, James D., Robert E. Sheridan, Kenneth G. Miller, Jane Uptegrove, Benjamin S. Cramer, and James V. Browning. "Late Pleistocene Sea level on the New Jersey Margin: Implications to eustasy and deep-sea temperature." Global and Planetary Change 66, no. 1-2 (March 2009): 93–99. http://dx.doi.org/10.1016/j.gloplacha.2008.03.013.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

35

Chiba, Takashi, Shigeo Sugihara, Yoshiaki Matsushima, Yusuke Arai, and Kunihiko Endo. "Crustal subsidence inferred from reconstruction of the Pleistocene–Holocene palaeogeography in the northern Lake Inba area, central Japan." Quaternary Research 94 (December 26, 2019): 61–79. http://dx.doi.org/10.1017/qua.2019.69.

Повний текст джерела

Анотація:

ABSTRACTTo help characterise the palaeogeographic and lacustrine environmental changes that resulted from the Holocene transgression and residual subsidence in the eastern Kanto Plain of central Japan, we analysed four drill cores and reviewed other core data from the southern part of the Lake Inba area. Fossil diatom assemblages yielded evidence of centennial-scale palaeogeographic and salinity responses to sea-level changes since the late Pleistocene. We determined that the seawater incursion into the Lake Inba area during the Holocene transgression occurred at approximately 9000 yr. We also recognised a late Holocene regression event corresponding to the Yayoi regression, considered to have occurred from ca. 3000 to ca. 2000 yr, and a subsequent transgression. Our data clarify some of the palaeogeographic changes that occurred in the Lake Inba area and document an overall trend toward lower salinity in the lake during the regression. In particular, the environment in Lake Inba changed from brackish to freshwater no later than 1000 yr. From the detailed palaeogeographic and palaeo-sea-level reconstruction, we recognised that residual subsidence occurred during the Holocene in this area. Thus, comparison of sea-level reconstructions based on modelling and fossil diatom assemblages is effective in interpreting Holocene long-term subsidence.

Стилі APA, Harvard, Vancouver, ISO та ін.

36

Müller, Anne. "Late- and Postglacial Sea-Level Change and Paleoenvironments in the Oder Estuary, Southern Baltic Sea." Quaternary Research 55, no. 1 (January 2001): 86–96. http://dx.doi.org/10.1006/qres.2000.2189.

Повний текст джерела

Анотація:

AbstractKnowledge of sea-level change in the southern Baltic Sea region is important for understanding the variations in late Pleistocene and Holocene sea-level change across northern Europe. These variations are a consequence of the response of the Earth's crust to the deglaciation of Fennoscandia and of the water added to the oceans from the melting of all Pleistocene ice sheets. The sedimentological and geochemical composition of five sediment cores from the lagoonal Oder Estuary offers new observational evidence for sea-level change and coastal development in the southern Baltic Sea region. The combined use of several geochemical proxies (organic carbon, nitrogen, calcium carbonate and biogenic opal contents, Corg/S and Corg/N ratios, δ13C values of organic matter, and δ15N values) is a new approach for the study area. The chemical evidence of this multiproxy approach allows clear identification of several stages in the development of the lagoonal environment: postglacial lake stages with sandy sedimentation during the Older Dryas and the Allerød stades, lacustrine phases with high autochthonous productivity during the Atlantic stade, terrestrial stages with peat formation at the beginning of the Subboreal stade, sedimentation as a result of marine transgression, and brackish sedimentation after the formation of sand spits and barrier islands during the Subatlantic stade. The stages are the result of regional sea-level change owing to complex shoreline development. They support the tentative sea-level curve proposed nearly 20 years ago for the region. In addition, changes in Oder River input in response to climate conditions is monitored. Whereas high terrigenous input of organic matter from the Oder River occurred during periods of humid climate during the Allerød, Atlantic, and Subatlantic stades, Oder River discharge decreased with drier and cooler climate conditions during the Subboreal stade. Furthermore, the geochemical evidence points to local anomalies such as the significance of river input and additional sulfate supply into the Oder lagoon for the composition of the sediments. Overall, the results provide a framework for future studies, which would allow for a more detailed comparison with other, similar environments.

Стилі APA, Harvard, Vancouver, ISO та ін.

37

Novico, F., C. Endyana, D. Menier, M. Mathew, I. Kurniawan, H. Bachtiar, D. Ranawijaya, and H. Hendarmawan. "The dynamic coastal evidence of Jakarta Bay during Late Pleistocene-Recent." IOP Conference Series: Earth and Environmental Science 930, no. 1 (December 1, 2021): 012002. http://dx.doi.org/10.1088/1755-1315/930/1/012002.

Повний текст джерела

Анотація:

Abstract Some significant indication identifying a coastal dynamic during Late Pleistocene to Recent is the evolution of isochrone patterns throughout glacial-interglacial stages. This study aims to identify the sediments stratification of Jakarta Bay during the Late Pleistocene – Recent in the framework of coastal dynamic triggered by the sea-level changes of last prominent climatic stages. The several high-resolution seismic records in Jakarta Bay lines were interpreted to illustrate the different sequences from the top down to the oldest by line-drawing the more robust seismic reflectors as a sequence limit surface. Furthermore, the isochrone map series of unit boundary (UB) were reconstructed to delineate isochrone contour patterns from the oldest until modern. The selected isochrones map of UB-3 and UB-5 with their unit facies are somehow favorable to be compared for observing the coastal dynamic of Jakarta Bay during the last climatic variability. Finally, the coastal dynamic of Jakarta Bay is discovered by the movement series of isochrones contour patterns that correspond to the sea-level changes during the last prominent glacial-interglacial stages.

Стилі APA, Harvard, Vancouver, ISO та ін.

38

Mendes, Vinícius Ribau, Paulo César Fonseca Giannini, Carlos Conforti Ferreira Guedes, Regina DeWitt, and Helena Asmar de Abreu Andrade. "Central Santa Catarina coastal dunefields chronology and their relation to relative sea level and climatic changes." Brazilian Journal of Geology 45, suppl 1 (August 2015): 79–95. http://dx.doi.org/10.1590/2317-4889201530143.

Повний текст джерела

Анотація:

ABSTRACTDuring the past decades, there have been contrarian explanations for the formation and stabilization of coastal dunefields: while many authors believe the dunes formation would be enhanced by falling sea level, others argue that a rising or stable sea level context would be favorable. For Brazilian coastal dunefields, the second hypothesis seems to be more consistent with the luminescence ages found so far; however, most of these data were obtained without using the SAR protocol. Another point of concern is the role of climate change in the aeolian system, which is still not very clear. The aim of this paper is to try to clarify these two questions. To this end, five coastal dunefields were selected in central Santa Catarina coast. The remote sensing and dating results allowed the discrimination and mapping of at least four aeolian generations. Their age distribution in relation to the global curve of relative sea level variation during the Late Pleistocene allows us to suggest that the formation of Aeolian dunefields in the coastal context is supported by stable relative sea level. However, relative sea level is not the only determinant for the formation and preservation of the aeolian coastal dunes. Evidences of climatic control indicate that the initiation of dunefields would be favored by periods of less humidity while their stabilization would occur preferably during the periods of rain intensification, connected to monsoon activity.

Стилі APA, Harvard, Vancouver, ISO та ін.

39

Gholami Zadeh, Parisa, and Alireza Shafeii. "Response of the Pliocene-Pleistocene carbonates to relative sea-level changes in Kish Island, Persian Gulf." Journal of African Earth Sciences 183 (November 2021): 104316. http://dx.doi.org/10.1016/j.jafrearsci.2021.104316.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

40

Adamson, K. R., J. C. Woodward, P. D. Hughes, F. Giglio, and F. Del Bianco. "Middle Pleistocene glaciation, alluvial fan development and sea-level changes in the Bay of Kotor, Montenegro." Geological Society, London, Special Publications 433, no. 1 (September 16, 2016): 193–209. http://dx.doi.org/10.1144/sp433.13.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

41

Caddah, Luiz Fernando G., Renato O. Kowsmann, and Adriano R. Viana. "Slope sedimentary facies associated with Pleistocene and Holocene sea-level changes, Campos Basin, southeast Brazilian Margin." Sedimentary Geology 115, no. 1-4 (January 1998): 159–74. http://dx.doi.org/10.1016/s0037-0738(97)00091-2.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

42

Schmincke, H. U., B. Behncke, M. Grasso, and S. Raffi. "Evolution of the northwestern Iblean Mountains, Sicily: uplift, Plicocene/Pleistocene sea-level changes, paleoenvironment, and volcanism." Geologische Rundschau 86, no. 3 (October 28, 1997): 637–69. http://dx.doi.org/10.1007/s005310050169.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

43

Nakada, Masao, Nobuyuki Yonekura, and Kurt Lambeck. "Late pleistocene and halocene sea-level changes in Japan: implications for tectonic histories and mantle rheology." Palaeogeography, Palaeoclimatology, Palaeoecology 85, no. 1-2 (May 1991): 107–22. http://dx.doi.org/10.1016/0031-0182(91)90028-p.

Повний текст джерела

Стилі APA, Harvard, Vancouver, ISO та ін.

44

Polidorou, Miltiadis, and Niki Evelpidou. "Geomorphology of the Coastal Sand Dune Fields and Their Association with the Palaeolandscape Evolution of Akrotiri Peninsula, Lemesos, Cyprus." Geosciences 11, no. 11 (October 30, 2021): 448. http://dx.doi.org/10.3390/geosciences11110448.

Повний текст джерела

Анотація:

Two well-developed late Pleistocene dune fields have been identified on the western and eastern side of Akrotiri promontory (Lemesos, Cyprus). The dune fields extend immediately from the low level of their source beaches onto higher ground (>48 m amsl). Geomorphic observations supported by OSL dating and sedimentological data provided evidence of the dune development and for the palaeogeographic reconstruction of the area. Relative sea level changes and wave action during the upper Pleistocene and Holocene played an important role into the development of the palaeolandscape and affected the formation of the dunes. From the collected data the development of the western dune field started at 56.2 ± 5.5 ka when the relative sea level was at approximately −60 m and contributed to the development of the western tombolo of the area whereas the eastern dune field developed in the late Holocene, after the formation of the eastern spit that resulted in the formation of the Akrotiri Salt lake.

Стилі APA, Harvard, Vancouver, ISO та ін.

45

Huang, Huai-Hsuan May, Moriaki Yasuhara, Hokuto Iwatani, Tatsuhiko Yamaguchi, Katsura Yamada, and Briony Mamo. "Deep-sea ostracod faunal dynamics in a marginal sea: biotic response to oxygen variability and mid-Pleistocene global changes." Paleobiology 45, no. 1 (November 23, 2018): 85–97. http://dx.doi.org/10.1017/pab.2018.37.

Повний текст джерела

Анотація:

AbstractDeep-sea benthic ostracod assemblages covering the last 2 Myr were investigated in Integrated Ocean Drilling Program Site U1426 (at 903 m water depth) in the southern Sea of Japan. Results show that (1) orbital-scale faunal variability has been influenced by eustatic sea-level fluctuations and oxygen variability and (2) secular-scale faunal transitions are likely associated with the mid-Brunhes event (MBE, ~0.43 Ma) and the onset of the Tsushima Warm Current (TWC, ~1.7 Ma).Krithe,Robertsonites, andAcanthocythereisare the three most abundant genera throughout the core, accounting for 78.5% of total specimens. Multiple-regression tree analysis indicated that the TWC, the MBE, and oxygen content are the significant controlling factors of ostracod dominance. Changes in assemblages exhibit decline and recovery patterns corresponding to orbital-scale cyclicity of sea-level changes. In the Sea of Japan marginal ocean setting, this cyclicity shows a close relationship with bottom-water oxygen variability since the onset of the TWC influx. The MBE amplified the influence of the TWC and oxygen variability to the deep-sea ecosystem through larger sea-level fluctuations.Acanthocythereis dunelmensis, a circumpolar species, dominates before the TWC onset. After the TWC onset and during the mid-Pleistocene transition (MPT, ~1.2–0.7 Ma)Krithespp., known for their low-oxygen tolerance, substantially increase under moderate oxygen depletion. At the end of the MPT,Krithedominance diminishes and is replaced byRobertsonites hanaiiandPropontocyprisspp. after the MBE. The post-MBE assemblage, characterized byR. hanaii, suggests a slightly warmer environment under the development of the TWC. In addition, the post-MBE high-amplitude climate system may have caused the increased abundance of active-swimmingPropontocyprisspp. due to their superior migration ability. Benthic ecosystems in marginal seas are sensitive and vulnerable to both short- and long-term climatic changes, and the MBE is suggested to be a global biotic event affecting benthic ecosystems substantially.

Стилі APA, Harvard, Vancouver, ISO та ін.

46

Savini, Alessandra, Valentina Alice Bracchi, Antonella Cammarosano, Micla Pennetta, and Filippo Russo. "Terraced Landforms Onshore and Offshore the Cilento Promontory (South-Eastern Tyrrhenian Margin) and Their Significance as Quaternary Records of Sea Level Changes." Water 13, no. 4 (February 23, 2021): 566. http://dx.doi.org/10.3390/w13040566.

Повний текст джерела

Анотація:

Climate change and tectonic uplift are the dominant forcing mechanisms responsible for the formation of long and narrow terraced landforms in a variety of geomorphic settings; and marine terraces are largely used to reconstruct the Quaternary glacial and interglacial climates. Along the Mediterranean coast, a considerable number of popular scientific articles have acknowledged a range of marine terraces in the form of low-relief surfaces resulting from the combined effects of tectonic uplift and eustatic sea-level fluctuations, as relevant geomorphological indicators of past sea-level high-stands. With the exception of a few recent studies on the significance of submarine depositional terraces (SDT), submerged terraced landforms have been less investigated. By integrating different marine and terrestrial datasets, our work brings together and re-examines numerous terraced landforms that typify the Cilento Promontory and its offshore region. In this area, studies since the 1960s have allowed the recognition of well-defined Middle to Upper Pleistocene marine terraces on land, while only a few studies have investigated the occurrences of late Pleistocene SDT. Furthermore, to date, no studies have consistently integrated findings. For our work, we correlated major evidence of emerged and submarine terraced landforms in order to support an improved understanding of the tectono-geomorphological evolution of the Cilento Promontory and to further clarify the geomorphological significance of submerged terraces.

Стилі APA, Harvard, Vancouver, ISO та ін.

47

Genov, Ivan. "The Black Sea level from the Last Glacial Maximum to the present time." Geologica Balcanica 45 (2016): 3–19. http://dx.doi.org/10.52321/geolbalc.45.0.3.

Повний текст джерела

Анотація:

Construction of the Black Sea level curve in the interval from the Last Glacial Maximum (LGM) to the present is the main purpose of this article. This curve was created on the basis of seismostratigraphic analysis and data from other investigations. Existing seismostratigraphic subdivisions have been corrected. The seismic sections of the uppermost part of the Upper Pleistocene and the Holocene display two sequences (cycles). Highstand normal regressive, forced regressive, lowstand normal regressive, and transgressive genetic units within the older sequence have been distinguished, i.e., all system tracts. The lowstand normal regressive tract in the younger sequence was not recognized in the seismic sections. This fact evidences catastrophic inundation of the brackish Black Sea from the Mediterranean (Marmara) salt waters during the Early Holocene. Synchronization between sea-level changes and climatic variations is shown. The Black Sea level in relation to the World Ocean level, the Marmara Sea level, and the Caspian Sea level have been examined. For this end, the ways and time of formation of the recognized subunits in seismic sections from the Dardanelles Strait, Marmara and Aegean Seas were explained. Juxtaposition between the results of this study and solutions of other investigations and hypotheses concerning the Black Sea level changes is done as a discussion. The chemical aragonite intercalations in the base of the sapropel mud, the seismostratigraphic analysis, and 14C dating prove redepositions over vast areas of seabed. The constructed Black Sea level curve is consistent with all data of different nature (e.g., sedimentological, climatic, biostratigraphic, seismostratigraphic, and 14C dating).

Стилі APA, Harvard, Vancouver, ISO та ін.

48

Gehrels, W. Roland. "Middle and Late Holocene Sea-Level Changes in Eastern Maine Reconstructed from Foraminiferal Saltmarsh Stratigraphy and AMS 14C Dates on Basal Peat." Quaternary Research 52, no. 3 (November 1999): 350–59. http://dx.doi.org/10.1006/qres.1999.2076.

Повний текст джерела

Анотація:

A relative sea-level history is reconstructed for Machiasport, Maine, spanning the past 6000 calendar year and combining two different methods. The first method establishes the long-term (103 yr) trend of sea-level rise by dating the base of the Holocene saltmarsh peat overlying a Pleistocene substrate. The second method uses detailed analyses of the foraminiferal stratigraphy of two saltmarsh peat cores to quantify fluctuations superimposed on the long-term trend. The indicative meaning of the peat (the height at which the peat was deposited relative to mean tide level) is calculated by a transfer function based on vertical distributions of modern foraminiferal assemblages. The chronology is determined from AMS 14C dates on saltmarsh plant fragments embedded in the peat. The combination of the two different approaches produces a high-resolution, replicable sea-level record, which takes into account the autocompaction of the peat sequence. Long-term mean rates of sea-level rise, corrected for changes in tidal range, are 0.75 mm/yr between 6000 and 1500 cal yr B.P. and 0.43 mm/yr during the past 1500 year. The foraminiferal stratigraphy reveals several low-amplitude fluctuations during a relatively stable period between 1100 and 400 cal yr B.P., and a sea-level rise of 0.5 m during the past 300 year.

Стилі APA, Harvard, Vancouver, ISO та ін.

49

Mahiques, Michel Michaelovitch de, and Luis Antonio Pereira de Souza. "Shallow seismic reflectors and upper Quaternary sea levei changes in the Ubatuba region, São Paulo State, Southeastern Brazil." Revista Brasileira de Oceanografia 47, no. 1 (1999): 01–10. http://dx.doi.org/10.1590/s1413-77391999000100001.

Повний текст джерела

Анотація:

The relationship between shallow seismic Wlits and Quaternary sea level changes in Southeastern Brazil is based on boomer profiles and core data ftom the Ubatuba region, northern São Paulo coast. In Flamengo and Palmas bays, the intecpretation of seismic lines revealed the occurrence of four sedimentary units, separated by regionally correlated reflectors. The upper two Wlits correspond to Late Pleistocene and Holocene deposits. The lowermost sedimentary units were correlated to the older Quaternary transgressive events. These deposits, which have not yet been described for this area, can presently be fOWld on the Rio Grande do Sul coastal plain. In the Boqueirão Strait, two erosional events in the sedimentary strata have been associated with the Cananéia (maximum at 120,000 yr. B.P.) and Santos (maximum at 5,100 yr. B.P.) sea-level rise events.

Стилі APA, Harvard, Vancouver, ISO та ін.

50

Nagai, Renata Hanae, Silvia Helena de Mello e. Sousa, Rafael André Lourenço, Márcia Caruso Bícego, and Michel Michaelovitch de Mahiques. "Paleoproductivity changes during the Late Quaternary in the southeastern Brazilian upper continental margin of the Southwestern Atlantic." Brazilian Journal of Oceanography 58, spe1 (2010): 31–41. http://dx.doi.org/10.1590/s1679-87592010000500004.

Повний текст джерела

Анотація:

Changes in the Brazilian continental margins oceanic productivity and circulation over the last 27,000 years were reconstructed based on sedimentological and microfaunal analyses. Our results suggest that oceanic paleoproductivity and the supply of terrigenous sediments to the Brazilian continental margin were higher during the Last Glacial Maximum (LGM) than during the Holocene. These changes may have been primarily influenced by significant sea level fluctuations that have occurred since the late Pleistocene. During the LGM, the lower sea level, higher productivity and lower sea-surface paleotemperatures may have been the result of the offshore displacement of the main flow of the Brazil Current. However, during the Holocene, the warm waters of the Brazil Current were displaced toward the coast. This displacement contributed to the increase in water temperature and prevented an increase in oceanic productivity. The decrease in terrigenous supply since the LGM could be related to the increase of the extension of the continental shelf and/or drier climatic conditions.

Стилі APA, Harvard, Vancouver, ISO та ін.

Статті в журналах з теми "Pleistocene sea level changes"

Оформте джерело за APA, MLA, Chicago, Harvard та іншими стилями