Journal articles on the topic 'Interglacial sedimentation'
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Li, Qianyu, Fan Zheng, Muhong Chen, Rong Xiang, Peijun Qiao, Lei Shao, and Xinrong Cheng. "Glacial Paleoceanography off the Mouth of the Mekong River, Southern South China Sea, During the last 500 ka." Quaternary Research 73, no. 3 (May 2010): 563–72. http://dx.doi.org/10.1016/j.yqres.2010.03.003.
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We have analyzed core MD01-2392, ∽360 km east of the Mekong River mouth in the South China Sea (SCS). Over the past 500 ka, planktonic foraminiferal oxygen-isotopic values are consistently lighter than northern SCS and open-ocean records by up to 0.5‰, indicating the influence of run-off from the Mekong River during both glacial and interglacial periods. Carbonate content is higher during interglacials; sedimentation rates were higher during glacials. Increased sedimentation rates since 30 ka imply increased run-off during the last glacial maximum and Holocene Period. Contrary to general experience, in which it is classed as a warm species for temperature estimates, the thermocline-dwelling species Pulleniatina obliquiloculata increased its numbers during glacial periods. This implies an estuarine circulation and even brackish-water caps during glacial periods, reinforcing the sense of strong run-off. In an overall decline of warm water, the thermocline shoaled stepwise, with rapid rises across the glacial terminations. We infer that the southern SCS was opened to an influx of Indian Ocean waters through southern passages at those times of rising sea levels.
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SEJRUP, H. P., and K. L. KNUDSEN. "Geochronology and palaeoenvironment of marine Quaternary deposits in Denmark: new evidence from northern Jutland." Geological Magazine 136, no. 5 (September 1999): 561–78. http://dx.doi.org/10.1017/s0016756899002964.
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The degree of isoleucine epimerization in the benthic foraminiferal species Elphidium excavatum and Bulimina marginata have been measured in four boreholes, penetrating marine interglacial beds, from northern Jutland. The results of these analyses are compiled with results obtained from other sites in Denmark and the North Sea region, and four aminozones (AZs) have been erected. AZ1 (aIle/Ile < 0.05) include the Late Weichselian and the Holocene part of the record. AZ2 (0.08–0.12) includes samples of last interglacial age. AZ3 (0.14–0.16) includes samples from sites that have been previously correlated with the Holsteinian, and marine isotope stage 7 age for this zone is suggested. An age close to 400±100 ka is assigned to AZ4 (0.21–0.26). AZ4 is recorded in corings at Skagen and Nørre Lyngby, and includes the here defined Skagerrak Interglacial, which is tentatively correlated with marine isotope stage 11.The Skagerrak Interglacial sediments are characterized by boreal lusitanian benthic foraminiferal faunas evidencing strong input of Atlantic water to the North Sea. These faunas are replaced by assemblages indicating cooler conditions at least twice during this period. The sedimentation pattern in northern Jutland during this interglacial seems to be different from the sedimentation regimes in the same area at the classical Eemian sites and during the Holocene, which were characterized by large sediment input from the Jutland Current. This difference may be attributed to a change in the geometry of the sedimentary basin through the later part of the Quaternary, which is a result of repeated periods of intense erosion in the confluence area of the Norwegian Channel ice stream. A strong influx of Atlantic water to the North Sea during stage 11 has been suggested earlier, based on records from the Devil's Hole area. However, the correlation of this event to the classic biostratigraphic based schemes of northwest Europe is still problematic.
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LÖWEMARK, LUDVIG, HUI-LING LIN, and MICHAEL SARNTHEIN. "Temporal variations of the trace fossil Zoophycos in a 425 ka long sediment record from the South China Sea: implications for the ethology of the Zoophycos producer." Geological Magazine 143, no. 1 (December 2, 2005): 105–14. http://dx.doi.org/10.1017/s0016756805001408.
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A 425 ka long record from piston core GIK17925-3 taken in the northeastern South China Sea was used to study the environmental conditions controlling the distribution of the Zoophycos trace fossil. The 12 m long core offers a unique opportunity to study the response of the Zoophycos-producing animal to environmental variations over four glacial–interglacial cycles. The trace fossils show a strong glacial to interglacial variation in their abundance with a special preference for intervals with low sedimentation rates. Additional X-ray radiograph studies of piston cores from the Southeast Asian Marginal Seas show that the trace fossil Zoophycos is widespread in slope and deep-marine sediments, with the highest abundances encountered in low sedimentation rate settings. The preference of the Zoophycos producer for low sedimentation rates in a setting with strong seasonal fluctuations in food supply due to the shift between winter and summer monsoons, is interpreted to be the result of a cache-model behaviour, where food is collected during rich times and squirrelled away for poor times. Core GIK17925-3 also offers an opportunity to assess the impact of Zoophycos bioturbation on various palaeoenvironmental proxies. In this core, more than 30 % of the measured data points were more or less strongly affected by Zoophycos bioturbation. Together with the widespread occurrence this percentage indicates that Zoophycos may pose a serious threat to palaeoclimatic reconstructions in cores from low to moderate sedimentation rate sites.
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Droxler, Andre W., and Wolfgang Schlager. "Glacial versus interglacial sedimentation rates and turbidite frequency in the Bahamas." Geology 13, no. 11 (1985): 799. http://dx.doi.org/10.1130/0091-7613(1985)13<799:gvisra>2.0.co;2.
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Gibbard, P. L., and J. Lewin. "Climate and related controls on interglacial fluvial sedimentation in lowland Britain." Sedimentary Geology 151, no. 3-4 (August 2002): 187–210. http://dx.doi.org/10.1016/s0037-0738(01)00253-6.
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Demidova, Svetlana V., Tatyana B. Rylova, and Galina K. Khursevich. "Paleogeographical conditions of the formation of Alexandrian (Likhvinian) sediments in the territory of Minsk." Issues of modern algology (Вопросы современной альгологии), no. 2(20) (2019): 201–4. http://dx.doi.org/10.33624/2311-0147-2019-2(20)-201-204.
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The article presents the results of studying the diatom method of interglacial Alexandrian (Likhvinian) sediments discovered by drilling in the city of Minsk. Diatom and spore-pollen data are compared. The environmental conditions of sedimentation in an ancient lake and the features of the vegetation of the surrounding area are characterized.
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Jonkers, H. A. "The Cockburn Island Formation; Late Pliocene interglacial sedimentation in the James Ross Basin, northern Antarctic Peninsula." Newsletters on Stratigraphy 36, no. 2-3 (August 11, 1998): 63–76. http://dx.doi.org/10.1127/nos/36/1998/63.
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Hepp, Daniel A., and Tobias Mörz. "An approach to quantifying Pliocene ice sheet dynamics via slope failure frequencies recorded in Antarctic Peninsula rise sediments." Antarctic Science 21, no. 6 (July 17, 2009): 619–31. http://dx.doi.org/10.1017/s0954102009990289.
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AbstractUnderstanding of glacially driven sedimentary transport systems across the shelf to the slope and subsequently to deep sea sediment bodies along the Pacific continental margin of Antarctic Peninsula is crucial for interpreting ice sheet dynamics. Here we quantify slope-failure frequencies recorded in Pliocene core intervals of ODP Site 1095. We used the relationship between long-term sedimentation rate and marine carbon burial efficiency to calculate glacial or interglacial specific sedimentation rates. Using the decompacted average length of glacial-interglacial cycles it was possible to solve a set of linear equations to derive average half-periods of 61.59 and 59.77 kyr respectively for the time interval 5.8–3.2 Ma. The resulting frequency distribution of slope failures reflects short and rapid but cyclic ice advances every ∼375 years. Short retention times between slope loading and slope failure are supported by biogenic silica dissolution analyses. This study demonstrates the potential of the rise record to improve models of orbitally controlled size variations of the West Antarctic ice sheet and confirms the hypothesis of a highly dynamic ice sheet during the early Pliocene warm period.
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Wang, Rong, Leonid Polyak, Weiyan Zhang, Xiaoguo Yu, Liming Ye, Linsen Dong, Yanguang Liu, Weiguo Wang, and Bernhard Diekmann. "Glacial-interglacial sedimentation and paleocirculation at the Northwind Ridge, western Arctic Ocean." Quaternary Science Reviews 258 (April 2021): 106882. http://dx.doi.org/10.1016/j.quascirev.2021.106882.
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Salabarnada, Ariadna, Carlota Escutia, Ursula Röhl, C. Hans Nelson, Robert McKay, Francisco J. Jiménez-Espejo, Peter K. Bijl, et al. "Paleoceanography and ice sheet variability offshore Wilkes Land, Antarctica – Part 1: Insights from late Oligocene astronomically paced contourite sedimentation." Climate of the Past 14, no. 7 (July 10, 2018): 991–1014. http://dx.doi.org/10.5194/cp-14-991-2018.
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Abstract. Antarctic ice sheet and Southern Ocean paleoceanographic configurations during the late Oligocene are not well resolved. They are however important to understand the influence of high-latitude Southern Hemisphere feedbacks on global climate under CO2 scenarios (between 400 and 750 ppm) projected by the IPCC for this century, assuming unabated CO2 emissions. Sediments recovered by the Integrated Ocean Drilling Program (IODP) at Site U1356, offshore of the Wilkes Land margin in East Antarctica, provide an opportunity to study ice sheet and paleoceanographic configurations during the late Oligocene (26–25 Ma). Our study, based on a combination of sediment facies analysis, magnetic susceptibility, density, and X-ray fluorescence geochemical data, shows that glacial and interglacial sediments are continuously reworked by bottom currents, with maximum velocities occurring during the interglacial periods. Glacial sediments record poorly ventilated, low-oxygenation bottom water conditions, interpreted as resulting from a northward shift of westerly winds and surface oceanic fronts. Interglacial sediments record more oxygenated and ventilated bottom water conditions and strong current velocities, which suggests enhanced mixing of the water masses as a result of a southward shift of the polar front. Intervals with preserved carbonated nannofossils within some of the interglacial facies are interpreted as forming under warmer paleoclimatic conditions when less corrosive warmer northern component water (e.g., North Atlantic sourced deep water) had a greater influence on the site. Spectral analysis on the late Oligocene sediment interval shows that the glacial–interglacial cyclicity and related displacements of the Southern Ocean frontal systems between 26 and 25 Ma were forced mainly by obliquity. The paucity of iceberg-rafted debris (IRD) throughout the studied interval contrasts with earlier Oligocene and post-Miocene Climate Optimum sections from Site U1356 and with late Oligocene strata from the Ross Sea, which contain IRD and evidence for coastal glaciers and sea ice. These observations, supported by elevated sea surface paleotemperatures, the absence of sea ice, and reconstructions of fossil pollen between 26 and 25 Ma at Site U1356, suggest that open-ocean water conditions prevailed. Combined, this evidence suggests that glaciers or ice caps likely occupied the topographic highs and lowlands of the now marine Wilkes Subglacial Basin (WSB). Unlike today, the continental shelf was not overdeepened and thus ice sheets in the WSB were likely land-based, and marine-based ice sheet expansion was likely limited to coastal regions.
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Palchan, Daniel, Ina Neugebauer, Yael Amitai, Nicolas D. Waldmann, Markus J. Schwab, Peter Dulski, Achim Brauer, Mordechai Stein, Yigal Erel, and Yehouda Enzel. "North Atlantic controlled depositional cycles in MIS 5e layered sediments from the deep Dead Sea basin." Quaternary Research 87, no. 1 (January 2017): 168–79. http://dx.doi.org/10.1017/qua.2016.10.
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AbstractThe drilled Inter-Continental Drilling Project core at the deeps of the Dead Sea reveals thick sequences of halite deposits from the last interglacial period, reflecting prevailing arid conditions in the lake’s watershed. Here, we examine sequences of intercalating evaporates (halite or gypsum) and fine-detritus laminae and apply petrographic, micro-X-ray fluorescence, and statistical tools to establish in high-temporal resolution the hydroclimatic controls on the sedimentation in the last interglacial Dead Sea. The time series of the thickness of the best-recovered core sections of the layered halite, detritus, and gypsum reveals periodicities of ~11, 7–8, and 4–5 yr, pointing to a North Atlantic control and possibly solar influence on the hydrology of the Dead Sea watershed during the regionally arid period of the last interglacial period. Similar periodicities were detected in the last glacial and modern sedimentary sequences of the Dead Sea and other archives of the central Levant, indicating a persistent impact of the solar cycles on regional hydrology, possibly through the effects of the North Atlantic Oscillation.
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Kleinen, Thomas, Victor Brovkin, and Guy Munhoven. "Modelled interglacial carbon cycle dynamics during the Holocene, the Eemian and Marine Isotope Stage (MIS) 11." Climate of the Past 12, no. 12 (November 29, 2016): 2145–60. http://dx.doi.org/10.5194/cp-12-2145-2016.
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Abstract. Trends in the atmospheric concentration of CO2 during three recent interglacials – the Holocene, the Eemian and Marine Isotope Stage (MIS) 11 – are investigated using an earth system model of intermediate complexity, which we extended with process-based modules to consider two slow carbon cycle processes – peat accumulation and shallow-water CaCO3 sedimentation (coral reef formation). For all three interglacials, model simulations considering peat accumulation and shallow-water CaCO3 sedimentation substantially improve the agreement between model results and ice core CO2 reconstructions in comparison to a carbon cycle set-up neglecting these processes. This enables us to model the trends in atmospheric CO2, with modelled trends similar to the ice core data, forcing the model only with orbital and sea level changes. During the Holocene, anthropogenic CO2 emissions are required to match the observed rise in atmospheric CO2 after 3 ka BP but are not relevant before this time. Our model experiments show a considerable improvement in the modelled CO2 trends by the inclusion of the slow carbon cycle processes, allowing us to explain the CO2 evolution during the Holocene and two recent interglacials consistently using an identical model set-up.
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Liu, Yuming, Xingxing Liu, Long Ma, Shugang Kang, Xiaoke Qiang, Fei Guo, and Youbin Sun. "Temporal–spatial variations in aeolian flux on the Chinese Loess Plateau during the last 150 ka." Geological Magazine 157, no. 5 (November 14, 2019): 757–67. http://dx.doi.org/10.1017/s0016756819001067.
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AbstractAeolian dust deposits from continent and ocean have been extensively investigated to reflect past changes in source aridity and atmospheric circulations. Aeolian flux (AF) as a quantitative dust proxy has been widely used in both palaeoenvironmental reconstruction and numerical simulation. However, available AF data on the Chinese Loess Plateau (CLP) is too limited to assess the temporal–spatial variations at glacial–interglacial timescales, and therefore cannot be used as robust input parameters in palaeoclimate models. Here we investigate eight loess profiles along two N–S-aligned transects on the CLP to quantitatively estimate the AF variations over the last glacial–interglacial cycle. We first establish a refined chronological framework based on optically stimulated luminescence chronology and pedostratigraphic correlation. AF was then estimated by multiplying the sedimentation rate and bulk density. The results show that the AF increases from 2–18 g cm−2 ka−1 in the southeastern CLP to 14–105 g cm−2 ka−1 in the northwestern CLP. At glacial–interglacial scales, the AF varies from 2–20 g cm−2 ka−1 during the last interglacial to 8–105 g cm−2 ka−1 in the last glaciation. Due to more spatial coverage and better age constraints, our AF data can be used to refine other AF datasets and to improve the proxy–model comparison.
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Francke, A., V. Wennrich, M. Sauerbrey, O. Juschus, M. Melles, and J. Brigham-Grette. "Multivariate statistic and time series analyses of grain-size data in quaternary sediments of Lake El'gygytgyn, NE Russia." Climate of the Past 9, no. 6 (November 5, 2013): 2459–70. http://dx.doi.org/10.5194/cp-9-2459-2013.
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Abstract. Lake El'gygytgyn, located in the Far East Russian Arctic, was formed by a meteorite impact about 3.58 Ma ago. In 2009, the International Continental Scientific Drilling Program (ICDP) at Lake El'gygytgyn obtained a continuous sediment sequence of the lacustrine deposits and the upper part of the impact breccia. Here, we present grain-size data of the past 2.6 Ma. General downcore grain-size variations yield coarser sediments during warm periods and finer ones during cold periods. According to principal component analysis (PCA), the climate-dependent variations in grain-size distributions mainly occur in the coarse silt and very fine silt fraction. During interglacial periods, accumulation of coarser material in the lake center is caused by redistribution of clastic material by a wind-induced current pattern during the ice-free period. Sediment supply to the lake is triggered by the thickness of the active layer in the catchment and the availability of water as a transport medium. During glacial periods, sedimentation at Lake El'gygytgyn is hampered by the occurrence of a perennial ice cover, with sedimentation being restricted to seasonal moats and vertical conduits through the ice. Thus, the summer temperature predominantly triggers transport of coarse material into the lake center. Time series analysis that was carried out to gain insight into the frequency of the grain-size data showed variations predominately on 98.5, 40.6, and 22.9 kyr oscillations, which correspond to Milankovitch's eccentricity, obliquity and precession bands. Variations in the relative power of these three oscillation bands during the Quaternary suggest that sedimentation processes at Lake El'gygytgyn are dominated by environmental variations caused by global glacial–interglacial variations (eccentricity, obliquity), and local insolation forcing and/or latitudinal teleconnections (precession), respectively.
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Murray, R. W., M. Leinen, D. W. Murray, A. C. Mix, and C. W. Knowlton. "Terrigenous Fe input and biogenic sedimentation in the glacial and interglacial equatorial Pacific Ocean." Global Biogeochemical Cycles 9, no. 4 (December 1995): 667–84. http://dx.doi.org/10.1029/95gb02833.
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Funder, S., O. Bennike, J. Böcher, C. Israelson, K. S. Petersen, and A. Símonarson. "Late Pliocene Greenland – The Kap København Formation in North Greenland." Bulletin of the Geological Society of Denmark 48 (December 31, 2001): 117–34. http://dx.doi.org/10.37570/bgsd-2001-48-06.
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The Kap København Formation, North Greenland, is a 100-m thick succession of predominantly shallow marine nearshore sediments, dated to c. 2.4 ma. The abundant well preserved remains of mosses, land plants, foraminifers, ostracodes, insects, cladocers, molluscs, and a few vertebrates enable a detailed reconstruction of terrestrial and marine environments and climate. The sediments indicate a complex sea-level history implying combined glacioisostatic and -eustatic control. This is supported by the faunal and floral development from arctic to subarctic and boreal conditions, and the record probably reflects the demise of the first major Cenozoic ice sheet, the Praetiglian, over the area, and the onset of the succeeding Tiglian A interglacial. The record ends with the attainment of the interglacial sea-level highstand and climate optimum when forest tundra reached the world’s northernmost coasts. It is inferred that the duration of sedimentation was a half obliquity cycle, i.e. 20,000 yr, at the most.
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Fedorowicz, Stanislaw, and Algirdas Gaigalas. "Geochronological and Sedimentological Interpretation of Interglacial Aquatic Sediments based on TL Dating." Geochronometria 35, no. -1 (January 1, 2010): 75–83. http://dx.doi.org/10.2478/v10003-010-0003-7.
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Geochronological and Sedimentological Interpretation of Interglacial Aquatic Sediments based on TL DatingFor the first time sedimentological interpretation of absolute ages obtained by thermoluminescence method on aquatic interglacial sediments was made. The analyzed size fractions of quartz grains were 160-250, 125-160, 100-125, 80-100 and 63-80 μm. The youngest and most reliable ages from 22 analyzed samples were obtained from the following quartz grain size granulometric fractions: 160-250 μm - 3 cases, 125-160 μm - 7, 100-125 μm - 6, 80-100 μm - 3 and 63-80 μm - 2 cases. Therefore, it may be concluded that the most suitable fractions for thermoluminescence dating are 125-160 μm and 100-125 μm. While evaluating the results of thermoluminescence dating it is necessary to take into account the procedure of sampling from layers of interest, their lithological composition, first of all granulometric, sedimentary environment, including sources of material, the material getting to the load flows, transportation mode and basin differentiation. From all the granulometric fractions of a sample, age of fine-grained fraction (63-80 μm) may be explained by the input of aeolian dust to a basin and sedimentation along with clasts brought to a lake by water flows. Aeolian sand storms performed precise multigenetic sedimentation that was active during that time. Bimodality of granulometric composition is defined by input of material from various sources of different composition. Older ages were obtained in the case of positive granulometric asymmetry. After sedimentological interpretation of thermoluminescence (TL) dating we can state that formation of aquatic fine-grained sands occurred 83.6±10 - 116.1±13 and 130.2±15 - 276.4±32 thousand years (ky) ago. Those geochronological zones coincide with interg lacial periods of Merkine (75.5-114 ky) and Snaigupele (180-280 ky) in Lithuania.
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Gasse, F., L. Vidal, A. L. Develle, and E. Van Campo. "Hydrological variability in the Northern Levant: a 250 ka multi-proxy record from the Yammoûneh (Lebanon) sedimentary sequence." Climate of the Past 7, no. 4 (November 24, 2011): 1261–84. http://dx.doi.org/10.5194/cp-7-1261-2011.
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Abstract. The Levant is a key region in terms of both long-term hydroclimate dynamics and human cultural evolution. Our understanding of the regional response to glacial-interglacial boundary conditions is limited by uncertainties in proxy-data interpretation and the lack of long-term records from different geographical settings. The present paper provides a 250 ka paleoenvironmental reconstruction based on a multi-proxy approach from northern Levant, derived from a 36 m lacustrine-palustrine sequence cored in the small intra-mountainous karstic Yammoûneh basin from northern Lebanon. We combined time series of sediment properties, paleovegetation, and carbonate oxygen isotopes (δc), to yield a comprehensive view of paleohydrologic-paleoclimatic fluctuations in the basin over the two last glacial-interglacial cycles. Integration of all available proxies shows that Interglacial maxima (early-mid MIS 7, MIS 5.5 and early MIS 1) experienced relatively high effective moisture, evidenced by the dominance of forested landscapes (although with different forest types) associated with authigenic carbonate sedimentation in a productive waterbody. Synchronous and steep δc increases can be reconciled with enhanced mean annual moisture when changes in seasonality are taken into account. During Glacials periods (MIS 2 and MIS 6), open vegetation tends to replace the forests, favouring local erosion and detrital sedimentation. However, all proxy data reveal an overall wetting during MIS 6, while a drying trend took place during MIS4-2, leading to extremely harsh LGM conditions possibly linked to water storage as ice in the surrounding highlands. Over the past 250 ka, the Yammoûneh record shows an overall decrease in local effective water, coincident with a weakening of seasonal insolation contrasts linked to the decreasing amplitude of the eccentricity cycle. The Yammoûneh record is roughly consistent with long-term climatic fluctuations in the northeastern Mediterranean region (except during MIS 6). It suggests that the role of seasonality on effective moisture, already highlighted for MIS 1, also explains older interglacial climate. The Yammoûneh record shares some features with speleothem isotope records of western Israel, while the Dead Sea basin generally evolved in opposite directions. Changes in atmospheric circulation, regional topographic patterns and site-specific hydrological factors are invoked as potential causes of spatial heterogeneities. Further work is needed to refine the Yammoûneh chronology, better understand its functioning through hydrological and climate modelling, and acquire other long records from northern Levant to disentangle the relative effects of local versus regional factors.
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Jedoui, Younes, Eric Davaud, Hedi Ben Ismaïl, and Jean-Louis Reyss. "Sedimentological analysis of marine Pleistocene deposits of southeastern Tunisia : evidence of two positive eustatic pulsations during the marine isotopic substage 5e (Eemian, Tyrrhenian)." Bulletin de la Société Géologique de France 173, no. 3 (May 1, 2002): 255–64. http://dx.doi.org/10.2113/173.3.255.
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Abstract Detailed sedimentological and petrographic analysis of marine Pleistocene deposits along the coastal area of southeastern Tunisia allow to identify two distinct lithostratigraphic units separated by an erosion surface (fig. 2 et 5 A and B). These two commonly superposed units form a ridge parallel to the coast. The palaeocoastal morphology was more irregular than the present-day coastline with areas either more protected or more exposed than now (fig. 3). The lower unit overlies an erosion surface cutting into Mio-Pliocene and Villafranchian deposits. It consists of fine-grained bioclastic quartz-rich sands (fig. 5 C), locally overlain by thin marl layers containing benthic foraminifera and ostracods. The very fine facies (silts and clays) represent relatively protected areas while the coarser facies developed in the more exposed zones. These deposits locally display a well-developed aeolian facies that terminates the sedimentary sequence. This unit, well developed in Jerba Island and Jorf peninsula, strongly resembles the stratigraphic unit of “Khnis” as defined by Mahmoudi [1988] on the coast of Central Tunisia. The upper unit is the better developed in the studied area. It consists of carbonate deposits composed mainly by ooids and peloids (fig. 5 D) and contains also a warm Senegalese fauna, especially Strombus. Locally, in the exposed areas, it shows a coarse facies which resulted mainly from the erosion of the calcareous Villafranchian deposits. This unit displays a remarkable shallowing-upward sequence from shoreface to aeolian dunes (fig. 5 E and F). It constitutes the lateral equivalent of the stratigraphic unit of “Réjiche” as defined by Mahmoudi [1988] in Central Tunisia. These two units, called in this study “quartz-rich unit” (the lower sequence) and “carbonate unit” (the upper one), developed during two distinctive sedimentation phases associated with two sea-level highstands separated by a marine regression. During the first highstand sea-level was about 3 m higher than today whereas it was at about +5 m during the second highstand [Jedoui, 2000]. Along the Mediterranean coasts the Strombus paleobeaches, which are contemporary with the carbonate unit, are well developed and traditionally called Tyrrhenian deposits. Their radiochemical dating, using corals, gives ages of about 125 ka [Hearty et al., 1986 ; Miller et al., 1986 ; Dumas et al., 1991 ; Vai et Pasini, 1996]. We obtained the most reliable uranium/thorium dates in southeastern Tunisia on oyster shells. Results show that the two units developed during the marine isotopic substage 5e [last interglacial ; Jedoui, 2000]. This evidence suggests that substage 5e was characterised by at least two eustatic maxima separated by a lowering of sea level during a marine regression. Our results are therefore in agreement with recent palaeoclimatic reconstructions and in particular with sea level reconstructions and marine oxygen isotope records that indicate the distinct possibility of two positive eustatic pulsations during the last interglacial [Hillaire-Marcel et al., 1996 ; Kindler et al., 1997 ; Plaziat et al., 1998]. Variations in the petrographic content of the two outlined units reflect drastic palaeoclimatic fluctuations in southeastern Tunisia during the last interglacial. The establishment of wetter climatic conditions at the beginning of marine isotopic substage 5e than today was responsible for an enhanced terrigenous materiel supply from the continent as showed by siliciclastic sedimentation along the coast (lower unit). Our data are in agreement with the strong sea surface salinity lowering observed in Mediterranean basins at the beginning of the last interglacial period [Kallel et al., 2000]. The regression of these conditions during the second half of the last interglacial favoured a carbonate sedimentation (upper unit) in southeastern Tunisia.
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Kaufman, Darrell S., Steven L. Forman, Peter D. Lea, and Cameron W. Wobus. "Age of Pre-late-Wisconsin Glacial-Estuarine Sedimentation, Bristol Bay, Alaska." Quaternary Research 45, no. 1 (January 1996): 59–72. http://dx.doi.org/10.1006/qres.1996.0006.
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AbstractPleistocene glacial-estuarine sediment deposited in an intertidal environment of northeastern Bristol Bay, southwestern Alaska, was dated using a variety of approaches, including infrared stimulated and thermoluminescence (IRSL and TL) techniques. Analysis of modern and 14C-dated Holocene tide-flat mud demonstrates that the bulk of sediment in this environment is reset by solar radiation, thereby lending confidence to ages obtained from similar Pleistocene deposits by luminescence techniques. IRSL seems to be especially well suited for dating, with resolution on time scales of <10,000 yr. The ages of tide-flat mud of the Nushagak Formation, derived from the Ahklun Mountains to the northwest of Bristol Bay, and of Halfmoon Bay drift, derived from the Alaska Peninsula to the southeast, suggest contemporaneous glacial-estuarine deposition related to independent glacial source areas about 75,000–80,000 yr ago. This age is consistent with other geochronological data that indicate a pre-late-Wisconsin and post-substage-5e age, including nonfinite 14C ages, a lack of interglacial indicators, and Old Crow tephra (∼140,000 yr) atop the drift, normal paleomagnetic inclinations, and amino acid (isoleucine) epimerization ratios (aIle/Ile). AIle/Ile ratios in Portlandia arctica(0.052 ± 0.003) from a marine-lag horizon at South Naknek beach, which separates Halfmoon Bay drift above from older glacial-estuarine drift below, are only slightly higher than in Mya truncata(0.041 ± 0.007) from last-interglacial Pelukian deposits at Nome. As laboratory heating experiments show that the two genera epimerize at similar rates, these data imply correlation of the marine lag at South Naknek beach with Pelukian deposits. Hence, glaciers on the Alaska Peninsula experienced major pre-late-Wisconsin advances both before and after the last interglaciation. Shells reworked into Halfmoon Bay drift yield aIle/Ile ratios of 0.028 ± 0.005 for Portlandiaat Second Point and 0.027 ± 0.001 for Hiatella arcticaat Etolin Point. Together with assumptions about the postdepositional temperature history, these ratios indicate that the shells are at least 55,000 yr, and probably closer to ∼90,000 yr, although the uncertainty in this age estimate is broad. The amino acid and luminescence data converge on an age between about 75,000, and 90,000 yr, late during oxygen-isotope stage 5, for a major ice advance far beyond late-Wisconsin limits.
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Pasquier, Virgil, Pierre Sansjofre, Marina Rabineau, Sidonie Revillon, Jennifer Houghton, and David A. Fike. "Pyrite sulfur isotopes reveal glacial−interglacial environmental changes." Proceedings of the National Academy of Sciences 114, no. 23 (May 22, 2017): 5941–45. http://dx.doi.org/10.1073/pnas.1618245114.
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The sulfur biogeochemical cycle plays a key role in regulating Earth’s surface redox through diverse abiotic and biological reactions that have distinctive stable isotopic fractionations. As such, variations in the sulfur isotopic composition (δ34S) of sedimentary sulfate and sulfide phases over Earth history can be used to infer substantive changes to the Earth’s surface environment, including the rise of atmospheric oxygen. Such inferences assume that individual δ34S records reflect temporal changes in the global sulfur cycle; this assumption may be well grounded for sulfate-bearing minerals but is less well established for pyrite-based records. Here, we investigate alternative controls on the sedimentary sulfur isotopic composition of marine pyrite by examining a 300-m drill core of Mediterranean sediments deposited over the past 500,000 y and spanning the last five glacial−interglacial periods. Because this interval is far shorter than the residence time of marine sulfate, any change in the sulfur isotopic record preserved in pyrite (δ34Spyr) necessarily corresponds to local environmental changes. The stratigraphic variations (>76‰) in the isotopic data reported here are among the largest ever observed in pyrite, and are in phase with glacial−interglacial sea level and temperature changes. In this case, the dominant control appears to be glacial−interglacial variations in sedimentation rates. These results suggest that there exist important but previously overlooked depositional controls on sedimentary sulfur isotope records, especially associated with intervals of substantial sea level change. This work provides an important perspective on the origin of variability in such records and suggests meaningful paleoenvironmental information can be derived from pyrite δ34S records.
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Dupont, L. M., T. Caley, J. H. Kim, I. Castañeda, B. Malaizé, and J. Giraudeau. "Glacial-interglacial vegetation dynamics in South Eastern Africa coupled to sea surface temperature variations in the Western Indian Ocean." Climate of the Past 7, no. 4 (November 9, 2011): 1209–24. http://dx.doi.org/10.5194/cp-7-1209-2011.
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Abstract. Glacial-interglacial fluctuations in the vegetation of South Africa might elucidate the climate system at the edge of the tropics between the Indian and Atlantic Oceans. However, vegetation records covering a full glacial cycle have only been published from the eastern South Atlantic. We present a pollen record of the marine core MD96-2048 retrieved by the Marion Dufresne from the Indian Ocean ∼120 km south of the Limpopo River mouth. The sedimentation at the site is slow and continuous. The upper 6 m (spanning the past 342 Ka) have been analysed for pollen and spores at millennial resolution. The terrestrial pollen assemblages indicate that during interglacials, the vegetation of eastern South Africa and southern Mozambique largely consisted of evergreen and deciduous forests. During glacials open mountainous scrubland dominated. Montane forest with Podocarpus extended during humid periods was favoured by strong local insolation. Correlation with the sea surface temperature record of the same core indicates that the extension of mountainous scrubland primarily depends on sea surface temperatures of the Agulhas Current. Our record corroborates terrestrial evidence of the extension of open mountainous scrubland (including fynbos-like species of the high-altitude Grassland biome) for the last glacial as well as for other glacial periods of the past 300 Ka.
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Dupont, L. M., T. Caley, J. H. Kim, I. Castaneda, B. Malaizé, and J. Giraudeau. "Glacial-interglacial vegetation dynamics in south eastern Africa depend on sea surface temperature variations in the west Indian Ocean." Climate of the Past Discussions 7, no. 4 (July 6, 2011): 2261–96. http://dx.doi.org/10.5194/cpd-7-2261-2011.
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Abstract. Glacial-interglacial fluctuations in the vegetation of South Africa might elucidate the climate system at the edge of the tropics between Indian and Atlantic Ocean. However, vegetation records covering a full glacial cycle have only been published from the eastern South Atlantic. We present a pollen record of the marine core MD96-2048 retrieved by the Marion Dufresne from the Indian Ocean ~120 km south of the Limpopo River mouth. The sedimentation at the site is slow and continuous. The upper 6 m (down till 342 ka) have been analysed for pollen and spores at millennial resolution. The terrestrial pollen assemblages indicate that during interglacials the vegetation of eastern South Africa and southern Mozambique largely consisted of evergreen and deciduous forests. During glacials open mountainous scrubland dominated. Montane forest with Podocarpus extended during humid periods favoured by strong local insolation. Correlation with the sea surface temperature record of the same core indicates that the extension of mountainous scrubland primarily depends on sea surface temperatures of the Agulhas Current. Our record corroborates terrestrial evidence of the extension of open mountainous scrubland (including elements with affinity to the Cape Flora) for the last glacial as well as for other glacial periods of the past 300 ka.
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Knudsen, Karen Luise. "Foraminifera in Late Elsterian-Holsteinian deposits of the Tornskov area in South Jutland, Denmark." Danmarks Geologiske Undersøgelse Serie B 10 (June 1, 1987): 7–31. http://dx.doi.org/10.34194/serieb.v10.7076.
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Foraminiferal faunas from marine Late Elsterian and Holsteinian deposits in the Tornskov borehole have been investigated. The faunal succession is correlated with the pollen zones of the same boring, and the assemblages are compared with Late Elsterian and Holsteinian faunas described from adjacent areas. Arctic foraminiferal faunas at the base of the marine sequence at Tornskov indicate that a marine transgression occurred prior to the establishment of full interglacial conditions, i.e. in the Late Elsterian. Marine sedimentation continued during much of the Holsteinian Interglacial. The assemblages here indicate boreal, mainly sublittoral conditions and relatively open access to the North Sea. Evidence for withdrawal of the Holsteinian sea from the area is not recorded in the faunas at Tornskov, the uppermost part of the marine sequence having probably been removed by subsequent glacial erosion. The general trend for corresponding deposits over the whole area of SW Denmark and N. Germany is that the regression took place before any indication of climatic deterioration is seen in either the fauna or the flora.
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Marchenko-Vagapova, T. "Paleogeographic conditions of sedimentation in the Rodionov interglacial period in the upper reaches of the Seyda River (according to palynological and diatom methods)." Vestnik of geosciences, no. 10 (December 7, 2022): 36–41. http://dx.doi.org/10.19110/geov.2022.10.4.
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We present results of study of Middle Pleistocene intermorainic deposits by palynological and diatom methods. Intermorainic deposits are assigned to the Rodionov interglacial period. Two climatic optima have been identified: pollen Pinus sylvestris dominates in the lower optimum, and pollen Picea sp., Pinus sylvestris dominates in the upper one. The deposits were generally formed in a shallow freshwater reservoir.
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Haesaerts, Paul, and Hans Mestdagh. "Pedosedimentary evolution of the last interglacial and early glacial sequence in the European loess belt from Belgium to central Russia." Netherlands Journal of Geosciences 79, no. 2-3 (August 2000): 313–24. http://dx.doi.org/10.1017/s001677460002179x.
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AbstractFor more than one century, the textural B-horizon of the last interglacial soil and its cover deposits have been standing out in Europe as an important pedostratigraphic marker. The complexity of this horizon was well illustrated since the seventies, though its pedological and stratigraphic significance remained doubtful. Macro-, meso- and micromorphological data gathered by the authors at various key-sites in Europe and the sequential correlation principle have resulted in a better understanding of the high complexity of the pedosedimentary and stratigraphical evolution of the last interglacial and early glacial loess succession. The present study identifies four megacyclic pedosedimentary intervals that show a general trend towards dry and continental climatic conditions.A consistent correlation exists between pedosedimentary evolution and vegetation, as recorded in the Grande Pile pollen record. The picture obtained in the present study is similar for both the Western and the Eastern European loess palaeosol successions. The so-called ‘last interglacial soil’, with three major soil-forming processes, belongs to the Eemian and Saint-Germain I (MIS substages 5e and 5c), whereas the humiferous sediments and soils on top are linked to Melisey II, Saint-Germain II and Ognon I (MIS substages 5b and 5a).The overlying loess, colluvial sediments and humiferous soils that end the palaeosol succession belong to the Ognon II and III interstadials; they record the onset of the early Pleniglacial (MIS stage 4) characterized by a significant increase in aeolian sedimentation.
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Francke, A., V. Wennrich, M. Sauerbrey, O. Juschus, M. Melles, and J. Brigham-Grette. "Multivariate statistic and time series analyses of grain-size data in Quaternary sediments of Lake El'gygytgyn, NE Russia." Climate of the Past Discussions 9, no. 1 (January 14, 2013): 217–44. http://dx.doi.org/10.5194/cpd-9-217-2013.
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Abstract. Lake El'gygytgyn, located in the Far East Russian Arctic, was formed by a meteorite impact about 3.58 Ma ago. In 2009, the ICDP Lake El'gygytgyn Drilling Project obtained a continuous sediment sequence of the lacustrine deposits and the upper part of the impact breccia. Here, we present grain-size data of the past 2.6 Ma. General downcore grain-size variations yield coarser sediments during warm periods and finer ones during cold periods. According to Principal Component Analyses (PCA), the climate-dependent variations in grain-size distributions mainly occur in the coarse silt and very fine silt fraction. During interglacial periods, accumulation of coarser grain sizes in the lake center is supposed to be caused by redistribution of clastic material by a wind-induced current pattern during the ice-free period. Sediment supply to the lake is triggered by the thickness of the active layer in the catchment, and the availability of water as transport medium. During glacial periods, sedimentation at Lake El'gygytgyn is hampered by the occurrence of a perennial ice-cover with sedimentation being restricted to seasonal moats and vertical conducts through the ice. Thus, the summer temperature predominantly triggers transport of coarse material into the lake center. Time series analysis that was carried out to gain insight in the frequency of the grain-size data showed grain-size variations predominately on Milankovitch's eccentricity, obliquity and precession bands. Variations in the relative power of these three oscillation bands during the Quaternary imply that climate conditions at Lake El'gygytgyn are mainly triggered by global glacial/interglacial variations (eccentricity, obliquity) and local insolation forcing (precession), respectively.
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Aksu, A. E., and David J. W. Piper. "Late Quaternary sedimentation in Baffin Bay." Canadian Journal of Earth Sciences 24, no. 9 (September 1, 1987): 1833–46. http://dx.doi.org/10.1139/e87-174.
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Baffin Bay is a small ocean basin that connects the Arctic and Atlantic oceans. The adjacent continental shelves have been extensively reworked during Quaternary glaciation. The shelf break generally lies between 200 and 500 m. The continental slope passes directly into the abyssal plain of Baffin Bay basin without any major submarine canyon – deep-sea fan system being present, except for a large smooth sediment apron in northern Baffin Bay.On the basis of over 50 piston cores, six Quaternary sediment facies are distinguished from detrital mineralogy (reflected in colour) and sediment texture. Facies A, B, and C are predominantly ice-rafted or are debris flow deposits, each with a distinct mineralogy. Facies D is turbidites and bottom-current sorted sands, silts, and muds. Facies E is hemipelagic sediment. Facies F consists of sediments ranging from slumps, through debris flow deposits, to fine-grained turbidites, with a distinctive provenance in northern Baffin Bay.These sediment facies appear to be partly controlled by glacial conditions. Hemipelagic facies E predominates during the present interglacial. During glacial stages, facies D turbidites were deposited. They resulted from slumping of proglacial sediments on the continental slopes off Greenland and Baffin Island. Facies C and F occurred on the continental slopes at these times. Ice-rafted facies A and B predominate at several horizons, reflecting a rapid breakup of ice shelves in northern Baffin Bay and increased rates of iceberg melting within the Bay. Overall sedimentation rates are relatively low, reflecting dry-base ice sheets in source areas.Deep-sea channel systems floored by sorted coarse sediments and bounded by muddy levees are absent in Baffin Bay, in contrast to mid-latitude glaciated continental margins off eastern Canada. These channel systems are the result of melting of wet-base glaciers, which provide a localized supply of sediment that is sorted by ice margin processes. In Baffin Bay, most glacial sediments are derived by calving of icebergs, probably from dry-base glaciers. Sediments are gradually released over large areas as the bergs melt, and are subsequently redistributed by debris flows.
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Baumgarten, H., T. Wonik, D. C. Tanner, A. Francke, B. Wagner, G. Zanchetta, R. Sulpizio, B. Giaccio, and S. Nomade. "Age–depth model of the past 630 kyr for Lake Ohrid (FYROM/Albania) based on cyclostratigraphic analysis of downhole gamma ray data." Biogeosciences 12, no. 24 (December 17, 2015): 7453–65. http://dx.doi.org/10.5194/bg-12-7453-2015.
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Abstract. Gamma ray (GR) fluctuations and potassium (K) values from downhole logging data obtained in the sediments of Lake Ohrid from 0 to 240 m below lake floor (b.l.f). correlate with fluctuations in δ18O values from the global benthic isotope stack LR04 (Lisiecki and Raymo, 2005). GR and K values are considered a reliable proxy to depict glacial–interglacial cycles, with high clastic input during cold and/or drier periods and high carbonate precipitation during warm and/or humid periods at Lake Ohrid. Spectral analysis was applied to investigate the climate signal and evolution over the length of the borehole. Linking downhole logging data with orbital cycles was used to estimate sedimentation rates and the effect of compaction was compensated for. Sedimentation rates increase on average by 14 % after decompaction of the sediment layers and the mean sedimentation rates shift from 45 cm kyr−1 between 0 and 110 m to 30 cm kyr−1 from 110 to 240 m b.l.f. Tuning of minima and maxima of gamma ray and potassium values versus LR04 extrema, in combination with eight independent tephrostratigraphical tie points, allows establishing of a robust age model for the downhole logging data over the past 630 kyr.
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McCave, I. N., T. Kiefer, D. J. R. Thornalley, and H. Elderfield. "Deep flow in the Madagascar–Mascarene Basin over the last 150000 years." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 363, no. 1826 (January 15, 2005): 81–99. http://dx.doi.org/10.1098/rsta.2004.1480.
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The SW Indian Ocean contains at least four layers of water masses with different sources: deep Antarctic (Lower Circumpolar Deep Water) flow to the north, midwater North Indian Deep Water flow to the south and Upper Circumpolar Deep Water to the north, meridional convergence of intermediate waters at 500–1500 m, and the shallow South Equatorial Current flowing west. Sedimentation rates in the area are rather low, being less than 1 cm ka −1 on Madagascar Ridge, but up to 4 cm ka −1 at Amirante Passage. Bottom flow through the Madagascar–Mascarene Basin into Amirante Passage varies slightly on glacial–interglacial time–scales, with faster flow in the warm periods of the last interglacial and minima in cold periods. Far more important are the particularly high flow rates, inferred from silt grain size, which occur at warm–to–cold transitions rather than extrema. This suggests the cause is changing density gradient driving a transiently fast flow. Corroboration is found in the glacial–interglacial range of benthic d 18 O which is ca. 2%, suggesting water close to freezing and at least 1.2 more saline and thus more dense glacial bottom waters than present. Significant density steps are inferred in isotope stage 6, the 5e–5d, and 5a–4 transitions. Oxygen isotope data suggest little change by mixing in glacial bottom water on their northward path. Benthic carbon isotope ratios at Amirante Passage differ from glacial Southern Ocean values, due possibly to absence of a local productivity effect present in the Southern Ocean.
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Veeh, H. H., D. C. McCorkle, and D. T. Heggie. "Glacial/interglacial variations of sedimentation on the West Australian continental margin: constraints from excess 230 Th." Marine Geology 166, no. 1-4 (May 2000): 11–30. http://dx.doi.org/10.1016/s0025-3227(00)00011-6.
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Moskalewicz, Damian. "Meandering style of fluvial sedimentation during the Eemian Interglacial in the Chlapowo Cliff section, North Poland." Quaternary International 279-280 (November 2012): 339–40. http://dx.doi.org/10.1016/j.quaint.2012.08.992.
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Demory, François, Gilles Conesa, Julien Oudet, Habib Mansouri, Philippe Münch, Jean Borgomano, Nicolas Thouveny, Juliette Lamarche, Franck Gisquet, and Lionel Marié. "Magnetostratigraphy and paleoenvironments in shallow-water carbonates: the Oligocene-Miocene sediments of the northern margin of the Liguro-Provençal basin (West Marseille, southeastern France)." Bulletin de la Société Géologique de France 182, no. 1 (January 1, 2011): 37–55. http://dx.doi.org/10.2113/gssgfbull.182.1.37.
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Abstract The present study proposes to estimate the influence of climate, eustatism and local tectonics on the sedimentation of a basin margin at the syn-rift to post-rift transition. For that, paleomagnetic measurements were performed on a marine marly-calcareous sedimentary succession ranging from Upper Oligocene to Lower Miocene and located on the northern margin of the Liguro-Provençal basin. The magnetostratigraphic record is correlated to the reference geomagnetic polarity scale [ATNTS04, Lourens et al. 2004] with the help of biostratigraphy based on calcareous nannofossils and planctonic foraminifers [Oudet et al., 2010]. The resulting age model shows that the 100 m-thick sedimentary succession covers a time span of 5 m.y. from the Late Chattian to the Early Burdigalian. Despite several exposure surfaces and a change in the sedimentation rate, no significant hiatus of sedimentation is documented. In addition, we also estimate the paleoenvironmental evolution through the sedimentary succession. Comparing the dated paleoenvironmental reconstruction with global δ18O and sea level curves [Miller et al., 2005], we show that the Carry-le-Rouet succession is an excellent paleoclimatic archive. Indeed, coral reefs developed at the glacial-interglacial stage transition marking the end of the Oligocene. In addition, the most diversified coral reefs occurred during the warmest period of the Aquitanian. During rifting, bathymetric variations recorded in the studied succession are related to local synsedimentary tectonics whereas, during oceanic crust accretion, global sea level changes influence the sedimentation. This result allows to characterise and to accurately date the break-up unconformity at 20.35 Ma.
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Van Vliet-Lanoë, Brigitte, Françoise Bergerat, Pascal Allemand, Christophe Innocentd, Hervé Guillou, Thibault Cavailhes, Águst Guðmundsson, et al. "Tectonism and volcanism enhanced by deglaciation events in southern Iceland." Quaternary Research 94 (November 22, 2019): 94–120. http://dx.doi.org/10.1017/qua.2019.68.
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AbstractSouthern Iceland is one of the main outlets of the Icelandic ice sheet and is subject to seismicity of both tectonic and volcanic origins along the South Iceland Seismic Zone (SISZ). A sedimentary complex spanning Marine Isotopic Stage 6 (MIS 6) to the present includes evidence of both activities. It includes a continuous sedimentary record since the Eemian interglacial period, controlled by a rapid deglaciation, followed by two marine glacioisostasy-forced transgressions, separated by a regression phase connected to an intra-MIS 5e glacial advance. This record has been constrained by tephrostratigraphy and dating. Analysis of this record has provided better insights into the interconnectedness of hydrology and volcanic and tectonic activity during deglaciations and glaciations. Low-intensity earthquakes recurrently affected the water-laid sedimentation during the early stages of unloading, accompanying rifting events, dyke injection, and fault reactivations. During full interglacial periods, earthquakes were significantly less frequent but of higher magnitude along the SISZ, due to stress accumulation, favored by low groundwater levels and more limited magma production. Occurrence of volcanism and seismicity in Iceland is commonly related to rifting events. Subglacial volcanic events seem moreover to have been related to stress unlocking related to limited or full unloading/deglaciation events. Major eruptions were mostly located at the melting margin of the ice sheet.
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Malkiewicz, Małgorzata. "The history of vegetation of the Eemian Interglacial in the Great Polish Lowland." Acta Societatis Botanicorum Poloniae 71, no. 4 (2014): 311–21. http://dx.doi.org/10.5586/asbp.2002.037.
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The subject of this paper is the history of vegetation in the Eemian Interglacial in southern Great Poland determined in the course of palaeobotanical research. Pollen analysis was conducted for lacustrine deposits from two localities (Grudzielec near Kalisz and Lechitów near Góra). The obtained pollen diagrams show diagnostic features of the Eemian. The succession of vegetation in both studied localities is characterised by three distinctive phases: protocratic with dominant pine-birch and birch-pine forest and communities of mixed pine-oak and oak forest. mesocratic with predominant hazel and well developed hornbeam-lime forest, and a telocratic one with widespread fir-spruce and pine forest. Moreover, the vegetation succession in top sections of the studied profiles was recognised as typical of the Early Vistulian. The presence of taxa with higher climatic requirements enabled the assessment of palaeoclimatic conditions in the Eemian climatic optimum of southern Great Poland. The development of vegetation in the Eemian Interglacial corresponds with the changes recorded in the nearby localities of Great Polish Lowland and other regions of Poland, as well as those of neighbouring countries. Some minor differences between the studied profiles result from different geographical location of the localities and various genesis of sedimentation basins.
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Pudsey, Carol J., and Angelo Camerlenghi. "Glacial–interglacial deposition on a sediment drift on the Pacific margin of the Antarctic Peninsula." Antarctic Science 10, no. 3 (September 1998): 286–308. http://dx.doi.org/10.1017/s0954102098000376.
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On the continental rise west of the Antarctic Peninsula there are nine large mounds interpreted as sediment drifts, separated by turbidity current channels. Drift 7 is 150 km long, 70 km wide and up to 700 m high and is asymmetric, with steep sides on the south-east (towards the continent) and south-west, and gentle slopes to north-west and north-east. Cores on the gentle sides of the drift show a cyclicity between brown, bioturbated, diatom-bearing mud with foraminifera and radiolarians, and grey, laminated, barren mud. Biostratigraphic evidence is consistent with a Late Quatermary age. Detailed lithostratigraphy and magnetic susceptibility data allow precise correlation over distances of tens of kilometres. On the basis of chemostratigraphy, the brown sediment is interpreted as interglacial (isotope stages 1 and 5) and the grey as glacial (stages 2–4 and 6). Sedimentation rates are 3.0–5.5 cm ka-1. Cores on the steep sides of the drift recovered a condensed section with thinner cycles and hiatuses. Fine grain size, very poor sorting and the absence of a mode in the silt size range indicate deposition from suspension with only weak current activity. There is little evidence for cyclic changes in bottom current strength. Supply of sediment to the benthic nepheloid layer was by entrainment of mud from turbidity currents, and by setting of pelagic material (biogenic grains, IRD, sediment suspended in meltwater plumes). Cyclic changes in sediment supply include more biogenic supply in interglacials with less sea ice cover, more terrigenous supply from turbidites in glacials with ice sheets grounded to the shelf edge, and changes in IRD content
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Mortyn, P. Graham, and Robert C. Thunell. "Biogenic sedimentation and surface productivity changes in the Southern California Borderlands during the last glacial—interglacial cycle." Marine Geology 138, no. 3-4 (May 1997): 171–92. http://dx.doi.org/10.1016/s0025-3227(96)00105-3.
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Gerasimenko, N. P., and І. P. Koval’chuk. "The Late Pleistocene soils as indicators of the impact of environmental changes on development of pedogenic processes (the study case from the Kryva Luka site, Donetsk area)." Journal of Geology, Geography and Geoecology 28, no. 2 (July 3, 2019): 262–74. http://dx.doi.org/10.15421/111927.
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The aim of this paper is to reveal connections between Upper Pleistocene soil types and the vegetation, which existed during their formation. Palaeovegetation was reconstructed on the basis of pollen analysis, whereas morphological description of palaeosols and the data from their laboratory study (grain-size and bulk chemical analyses, contents of Corg., CaCO3 and dry salts) were used to reconstruct palaeopedological processes. The Kryva Luka sedimentary sequence was accumulated in a deep palaeogully (the incision of which occurred in early Kaydaky times), where, as a result of high sedimentation rates, welldeveloped Upper Pleistocene pedocomplexes formed, on one hand, and very good preservation of pollen was thus guaranteed. Several phases of soil development occurred in Kaydaky, Pryluky and Vytachiv times (the Ukrainian Quaternary framework), all represented in the section by individual palaeosols, separated by loess-like beds, or by erosional surfaces. The data collected demonstrates a cyclic pattern of short-period palaeoenvironmental changes during the Late Pleistocene. The last interglacial is related by paleopedological and pollen data to the Kaydaky unit. The pre-temperate stage of the interglacial is revealed in the gully deposits of subunit ‘kd1a’. The early-temperate stage corresponds to the Luvisol of subunit ‘kd1b’, which was formed under broad-leaved woods dominated by oak. The late-temperate stage is recorded in the Greyzemic Phaeozem of the soil ‘kd3b1’ (by the appearance of hornbeam) and the Mollisol ‘kd3b2’. The post-temperate stage of the interglacial and the transition to the early glacial occurred during formation of the uppermost bed of thelatter and the incipient soil ‘kd3c’. (pedosediments were also accumulated at this time). Both vegetational composition and the soil types reflect a warmer and wetter climate for the temperate part of the last interglacial, as compared to that existing in modern times. The soils of different phases of Pryluky and Vytachiv times were formed during interstadials, with cooler climates than at present. As recorded both in soil types and pollen assemblages, the climates during the early interstadials of Pryluky and Vytachiv times were wetter than now (particularly during the ‘pl1b1’ phase), but during their late interstadials, the climate was drier than the modern one (particularly during the phase ‘pl3b2’). On the basis of TL-dating obtained in sections in western Donetsk area and Central Ukraine, Pryluky times correspond to interstadials and stadials of the early glacial, whereas Vytachiv unit may be related to the middle pleniglacial. Types of cryostructures, connected with loess-like deposits of the stadials, indicate that the studied area in those times was under a severe continental climate, with deep seasonal freezing of the grounds. Nevertheless, the absence of ice pseudomorphs and of pollen of arctoalpine plants indicates that permafrost was not present. Changes in palaeopedogenic processes (as well as in types of sedimentation) mainly paralleled changes observed in the palaeovegetation. The extent of wooded areas, the role of broad-leaved trees in the forest composition, and the spread of xeric herbal associations had particularly notable effects on the development of pedogenic processes.
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Pickarski, Nadine, and Thomas Litt. "A new high-resolution pollen sequence at Lake Van, Turkey: insights into penultimate interglacial–glacial climate change on vegetation history." Climate of the Past 13, no. 6 (June 14, 2017): 689–710. http://dx.doi.org/10.5194/cp-13-689-2017.
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Abstract. A new detailed pollen and oxygen isotope record of the penultimate interglacial–glacial cycle, corresponding to the marine isotope stage (MIS) 7–6, has been generated from the Ahlat Ridge (AR) sediment core at Lake Van, Turkey. The presented Lake Van pollen record (ca. 250.2–128.8 ka) displays the highest temporal resolution in this region with a mean sampling interval of ∼ 540 years.The integration of all available proxies shows three temperate intervals of high effective soil moisture availability. This is evidenced by the predominance of steppe-forested landscapes (oak steppe-forest) similar to the present interglacial vegetation in this sensitive semiarid region between the Black Sea, the Caspian Sea, and the Mediterranean Sea.The wettest and warmest stage, as indicated by highest temperate tree percentages, can be broadly correlated with MIS 7c, while the amplitude of the tree population maximum during the oldest penultimate interglacial (MIS 7e) appears to be reduced due to warm but drier climatic conditions. The detailed comparison of the penultimate interglacial complex (MIS 7) to the last interglacial (Eemian, MIS 5e) and the current interglacial (Holocene, MIS 1) provides a vivid illustration of possible differences in the successive climatic cycles. Intervening periods of treeless vegetation can be correlated with MIS 7d and 7a, in which open landscapes favor local erosion and detrital sedimentation. The predominance of steppe elements (e.g., Artemisia, Chenopodiaceae) during MIS 7d indicates very dry and cold climatic conditions. In contrast, the occurrence of higher temperate tree percentages (mainly deciduous Quercus) throughout MIS 7b points to relatively humid and mild conditions, which is in agreement with other pollen sequences in southern Europe.Despite the general dominance of dry and cold desert-steppe vegetation during the penultimate glacial (broadly equivalent to MIS 6), this period can be divided into two parts: an early stage (ca. 193–157 ka) with higher oscillations in tree percentages and a later stage (ca. 157–131 ka) with lower tree percentages and subdued oscillations. This subdivision of the penultimate glacial is also seen in other pollen records from southern Europe (e.g., MD01-2444 and I-284; Margari et al., 2010; Roucoux et al., 2011). The occurring vegetation pattern is analogous to the division of MIS 3 and MIS 2 during the last glacial in the same sediment sequence. Furthermore, we are able to identify the MIS 6e event (ca. 179–159 ka) as described in marine pollen records, which reveals clear climate variability due to rapid alternation in the vegetation cover.In comparison with long European pollen archives, speleothem isotope records from the Near East, and global climate parameters (e.g., insolation, atmospheric CO2 content), the new high-resolution Lake Van record presents an improved insight into regional vegetation dynamics and climate variability in the eastern Mediterranean region.
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Yao, Zhengquan, Xuefa Shi, Qingsong Liu, Yanguang Liu, Juan Cruz Larrasoaña, Jianxing Liu, Shulan Ge, et al. "Paleomagnetic and astronomical dating of sediment core BH08 from the Bohai Sea, China: Implications for glacial–interglacial sedimentation." Palaeogeography, Palaeoclimatology, Palaeoecology 393 (January 2014): 90–101. http://dx.doi.org/10.1016/j.palaeo.2013.11.012.
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Baumgarten, H., T. Wonik, D. C. Tanner, A. Francke, B. Wagner, G. Zanchetta, R. Sulpizio, B. Giaccio, and S. Nomade. "Age depth-model for the past 630 ka in Lake Ohrid (Macedonia/Albania) based on cyclostratigraphic analysis of downhole gamma ray data." Biogeosciences Discussions 12, no. 10 (May 22, 2015): 7671–703. http://dx.doi.org/10.5194/bgd-12-7671-2015.
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Abstract. We report the gamma ray fluctuations from downhole logging data obtained in the sediments of Lake Ohrid from 0 to 240 m below lake floor. These variations in gamma ray and potassium values strongly correlate with fluctuations in global δ18O values and can be thus considered a reliable proxy to depict glacial–interglacial cycles, with high clastic input during cold and/or drier periods and high carbonate precipitation during the warm and/or humid periods in Lake Ohrid. Spectral analysis (sliding window) was applied to investigate the climate signal and their evolution over the length of the borehole. Linking the downhole logging data with orbital cycles was used to estimate sedimentation rates, which shift from 45 cm ka−1 between 0 to 110 m to 30 cm ka−1 from 110 to 240 m below lake floor. The effect of compaction was compensated for. Sedimentation rates increase on average by 14% after decompaction of the sediment layers. Tuning of minima and maxima in gamma ray and potassium values vs. LR04 minima and maxima, in combination with eight independent tephrostratigraphical tie points, allows the establishment of a robust age model for the downhole logging data over the past 630 ka in Lake Ohrid.
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Cohen, K. M., P. L. Gibbard, and H. J. T. Weerts. "North Sea palaeogeographical reconstructions for the last 1 Ma." Netherlands Journal of Geosciences - Geologie en Mijnbouw 93, no. 1-2 (June 2014): 7–29. http://dx.doi.org/10.1017/njg.2014.12.
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AbstractThe landscape evolution of the southern North Sea basin is complex and has left a geographically varying record of marine, lacustrine, fluvial and glacial sedimentation and erosion. Quaternary climatic history, which importantly included glaciation, combined with tectonics gave rise to cyclic and non-cyclic changes of sedimentation and erosion patterns. Large-scale landscape reorganisations left strong imprints in the preserved record, and are important for the detail that palaeogeographical reconstructions for the North Sea area can achieve. In the spirit of the North Sea Prehistory Research and Management Framework (NSPRMF; Peeters et al., 2009), this paper provides background geological information regarding the North Sea. It summarises current stratigraphical and chronological frameworks and provides an overview of sedimentary environments. As we go back in time, the understanding of Quaternary palaeo-environmental evolution in the North Sea basin during the last 1 million years becomes decreasingly accurate, with degree of preservation and accuracy of age control equally important controls. Comparing palaeogeographical reconstructions for the Middle Pleistocene, the last interglacial-glacial cycle and the period following the Last Glacial Maximum illustrates this. More importantly, a series of palaeogeographical maps provide an account of basin-scale landscape change, which provides an overall framework for comparing landscape situations through time.
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Chen, Jun, Junfeng Ji, Yang Chen, Zhisheng An, John A. Dearing, and Yongjin Wang. "Use of Rubidium to Date Loess and Paleosols of the Louchan Sequence, Central China." Quaternary Research 54, no. 2 (September 2000): 198–205. http://dx.doi.org/10.1006/qres.2000.2159.
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Rb concentrations, analyzed at 20-cm intervals from the Luochuan sequence of loess and paleosols, are sensitive to the loess–paleosol alternation controlled by monsoon climate. Because it is geochemically immobile, Rb can be well preserved in the loess–paleosol sequence after deposition, and its concentration depends mainly on properties of the winter monsoon-blown dust and on intensity of the summer monsoon-induced pedogenesis. A curvilinear relation has been developed between the measured Rb-concentration and the apparent sedimentation rate for the last glacial–interglacial cycle. This relation provides a time scale that corresponds well with the presently accepted ages for paleomagnetic reversals of Brunhes/Matuyama and Jaramillo events. With allowance for reduced Rb concentrations caused by early Pleistocene climate, the Rb-based time scale is also consistent with the boundary ages of other major paleomagnetic reversals of the past 2.58 myr.
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Sadori, L., A. Koutsodendris, A. Masi, A. Bertini, N. Combourieu-Nebout, A. Francke, K. Kouli, et al. "Pollen-based paleoenvironmental and paleoclimatic change at Lake Ohrid (SE Europe) during the past 500 ka." Biogeosciences Discussions 12, no. 18 (September 17, 2015): 15461–93. http://dx.doi.org/10.5194/bgd-12-15461-2015.
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Abstract. Lake Ohrid is located at the border between FYROM and Albania and formed during the latest phases of Alpine orogenesis. It is the deepest, the largest and the oldest tectonic lake in Europe. To better understand the paleoclimatic and paleoenvironmental evolution of Lake Ohrid a deep drilling was carried out in 2013 within the framework of the Scientific Collaboration on Past Speciation Conditions (SCOPSCO) project that was funded by the International Continental Drilling Program (ICDP). Preliminary results indicate that lacustrine sedimentation of Lake Ohrid started between 1.2 and 1.9 Ma ago. Here we present new pollen data (selected percentage and concentration taxa/groups) of the uppermost ~200 m of the 569 m-long DEEP core drilled in the depocenter of Lake Ohrid. The study is the fruit of a cooperative work carried out in several European palynological laboratories. The age model is based on nine tephra layers and on tuning of biogeochemical proxy data to orbital parameters and to the global benthic isotope stack LR04. According to the age model the studied sequence covers the last ~500 000 years at a millennial-scale resolution (~1.6 ka) and record the major vegetation and climate changes that occurred during the last 12 (13 only pro parte) marine isotope stages (MIS). Our results indicate that there is a general good correspondence between forested/non-forested periods and glacial/interglacial cycles of marine isotope stratigraphy. Our record shows a progressive change from cooler and wetter to warmer and dryer interglacial conditions. This shift is visible also in glacial vegetation. The interglacial phase corresponding to MIS11 (pollen assemblage zone, PAZ OD-12, 488–455 ka BP and OD-19, 367–328 ka BP) is dominated by montane trees such as conifers. The two younger interglacial periods, MIS5 (PAZ OD-3, 126–70 ka BP) and MIS1 (PAZ OD-1, 12 ka BP to present) are marked by dominance of mesophilous elements such as deciduous and semi-deciduous oaks. Moreover, MIS7 (PAZ OD-6, 245–189 ka) shows a very high interglacial variability, with alternating expansions of montane and mesophilous arboreal taxa. Grasslands (open vegetation formations requiring relatively humid conditions) characterize the first glacial phases of MIS12 (PAZ OD-12, 488–455 ka), MIS10 (corresponding to PAZ OD-10, 421–367 ka) and MIS8 (PAZ OD-7, 285–245 ka). Steppes (open vegetation formations typical of dry environments) prevail during MIS6 (OD-5 and OD-4, 189–126 ka) and during MIS4–2 (PAZ OD-2, 70–12 ka). Our palynological results support the notion that Lake Ohrid has been a refugium area for both temperate and montane trees during glacials. Close comparisons with other long southern European and Near Eastern pollen records will be achieved through ongoing high-resolution studies.
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Minyuk, P. S., V. Ya Borkhodoev, and V. Wennrich. "Inorganic data from El'gygytgyn Lake sediments: stages 6–11." Climate of the Past Discussions 9, no. 1 (January 21, 2013): 393–433. http://dx.doi.org/10.5194/cpd-9-393-2013.
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Abstract. Geochemical study was performed on sediment of deep drilling core from El'gygytgyn Lake, located in central Chukotka, northeastern Russia (67°30' N; 172°05' E). Major and rare elements were determined by X-ray fluorescence spectroscopy (XRF) on 600 samples covering the timeframe between ca. 450 and 125 ka corresponding to Marine Isotope Stages (MIS) 11 to 6. Inorganic geochemistry data indicates significant variations in the elemental compositions corresponding to the glacials and interglacials periods. Interglacial sediments are characterized by high contents of SiO2, Na2O, CaO, K2O, Sr and are depleted in Al2O3, Fe2O3, TiO2, MgO. Extreme enrichments in SiO2 during MIS 11.3 and 9.3 are caused by an enhanced flux of biogenic silica (BSi). Geochemical structure of stage 11 shows very similar peculiarities to features of stage 11 from records of Lake Baikal/SE Siberia and Antarctic ice cores. High contents of TiO2, Fe2O3, MgO, Al2O3, LOI, Ni, Cr and Zr are typical for sediments of glacial stages, among those MIS 7.4 and 6.6 are the most marked. Peaks in the Fe2O3 content and coinciding low Fe2O3/MnO ratios during glacials indicate reducing condition in the sediments. This is also supported by enrichments in P2O5 and MnO, indicating an increased abundance of authigenic fine grained vivianite. Some elemental ratios indicate an enhanced alteration of glacial sediments accompanied by a loss of mobile elements, like Na, Ca, K and Sr. The higher alteration of sediments can presumably be traced back to changes in the sedimentation regime and diagenetic processes, and thus, reflects environmental changes.
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Thomson, J., S. Nixon, C. P. Summerhayes, J. Schönfeld, R. Zahn, and P. Grootes. "Implications for sedimentation changes on the Iberian margin over the last two glacial/interglacial transitions from (230Thexcess)0 systematics." Earth and Planetary Science Letters 165, no. 3-4 (February 1999): 255–70. http://dx.doi.org/10.1016/s0012-821x(98)00265-9.
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Olson, Hilary Clement, John E. Damuth, and C. Hans Nelson. "Latest Quaternary sedimentation in the northern Gulf of Mexico intraslope basin province: II — Stratigraphic analysis and relationship to glacioeustatic climate change." Interpretation 4, no. 1 (February 1, 2016): SC81—SC95. http://dx.doi.org/10.1190/int-2015-0111.1.
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Stratigraphic zonation of 139 piston cores from the intraslope basin province of the northern Gulf of Mexico based on the Globorotalia menardii complex and calcium carbonate fluctuations shows that the vast majority of the cores contain sediments only of Holocene (Z zone) and Late Wisconsin (Y zone, Last Glacial) age. Only 13 widely spaced cores penetrate sediments of Last Interglacial (X zone) age. Overall, sedimentation rates average approximately 13 cm for the Holocene, but they range up to 600 cm. Redeposited sediments (mass-transport deposits and/or turbidites) occur in cores from the Rio Grande Submarine Fan, the East Breaks Slide Complex, the Trinity-Brazos Turbidite System, and the Bryant Canyon Turbidite System. Stratigraphic zonation of suites of cores from these areas shows that nearly all of these deposits were emplaced during Late Wisconsin (Y zone, Last Glacial). Redeposited sediments in the Holocene (Z zone) are rare.
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Amorosi, Alessandro, Maria Luisa Colalongo, Fabio Fusco, Giancarlo Pasini, and Flavia Fiorini. "Glacio-Eustatic Control of Continental–Shallow Marine Cyclicity from Late Quaternary Deposits of the Southeastern Po Plain, Northern Italy." Quaternary Research 52, no. 1 (July 1999): 1–13. http://dx.doi.org/10.1006/qres.1999.2049.
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Integrated sedimentological and micropaleontological (foraminifera, ostracods, pollens) investigations of a 173-m-long continuous core in the subsurface of the SE Po Plain reveal a cyclic facies distribution of continental to shallow-marine deposits. Radiometric and pollen data enable an age attribution of the study units to the late Middle Pleistocene–Holocene. Glacioeustasy appears to have exerted a major control on facies development, as documented by the close relationships between cyclic lithofacies patterns and the curves of eustatic fluctuation. Particularly, relative sea-level falls and lowstand phases were characterized by the development of alluvial sedimentation, whereas major transgressive pulses and subsequent highstands are reflected by abrupt shifts to paralic and shallow-marine deposits. This facies architecture is paralleled by a distinctive pollen distribution, reflecting the alternation of a glacial type of vegetation, dominated by Pinus and nonarboreal pollen types, with interglacial mixed deciduous broad-leaved forests.
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Pico, T. "Towards assessing the influence of sediment loading on Last Interglacial sea level." Geophysical Journal International 220, no. 1 (October 9, 2019): 384–92. http://dx.doi.org/10.1093/gji/ggz447.
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SUMMARY Locally, the elevation of last interglacial (LIG; ∼122 ka) sea level markers is modulated by processes of vertical displacement, such as tectonic uplift or glacial isostatic adjustment, and these processes must be accounted for in deriving estimates of global ice volumes from geological sea level records. The impact of sediment loading on LIG sea level markers is generally not accounted for in these corrections, as it is assumed that the impact is negligible except in extremely high depositional settings, such as the world's largest river deltas. Here we perform a generalized test to assess the extent to which sediment loading may impact global variability in the present-day elevation of LIG sea level markers. We numerically simulate river sediment deposition using a diffusive model that incorporates a migrating shoreline to construct a global history of sedimentation over the last glacial cycle. We then calculate sea level changes due to this sediment loading using a gravitationally self-consistent model of glacial isostatic adjustment, and compare these predictions to a global compilation of LIG sea level data. We perform a statistical analysis, which accounts for spatial autocorrelation, across a global compilation of 1287 LIG sea level markers. Though limited by uncertainties in the LIG sea level database and the precise history of river deposition, this analysis suggests there is not a statistically significant global signal of sediment loading in LIG sea level markers. Nevertheless, at sites where LIG sea level markers have been measured, local sea level predicted using our simulated sediment loading history is perturbed up to 16 m. More generally, these predictions establish the relative sensitivity of different regions to sediment loading. Finally, we consider the implications of our results for estimates of tectonic uplift rates derived from LIG marine terraces; we predict that sediment loading causes 5–10 m of subsidence over the last glacial cycle at specific locations along active margin regions such as California and Barbados, where deriving long-term tectonic uplift rates from LIG shorelines is a common practice.
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Van Vliet-Lanoë, Brigitte, Jean-Luc Schneider, Águst Guðmundsson, Hervé Guillou, Sébastien Nomade, Gilles Chazot, Céline Liorzou, and Solène Guégan. "Eemian estuarine record forced by glacio-isostasy (southern Iceland)—link with Greenland and deep sea records." Canadian Journal of Earth Sciences 55, no. 2 (February 2018): 154–71. http://dx.doi.org/10.1139/cjes-2017-0126.
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Central southern Iceland is one of the main outlets of the Icelandic Ice Sheet where a MIS 5e sedimentary complex, the Rangá Formation, is extensively observed below the last deglaciation terminal moraines. Sedimentary facies demonstrate that the Rangá Formation is mostly tidal, up to 215 m (transgression I) and 168 m (transgression II) in altitude. The first highstand reworks a thick tephra from the Grimsvötn volcano, known in marine cores as 5e low/Bas-IV and positioned at ca. 127 Ka BP, the Eemian thermal optimum. This formation is related to a rapid deglaciation followed by two marine transgressions marked by the development of extended mud flats, which were separated by a complex regression phase, associated with loess deposition, ca. 9 Ka in duration. Palaeo jökulhlaups, basaltic flows, and tephra fallouts from the Hekla and Grimsvötn volcanoes affected the sedimentation. The Rangá Formation yields one of the first continuous and complete estuarine records of the Eemian interglacial in Iceland and probably for most of the northern terrestrial Atlantic. This estuarine infill records the distal signature of a complex glacial advance within the last interglacial, already well identified in northern and central Iceland. The glacial advance is attributed to the intra-Eemian cooling events (Greenland GS 26 or marine cold events M-C25-C26). It is followed by a warming and a glacial retreat corresponding to the Greenland GI 25 event. This formation allows, in connection with the timing of recognized volcanic periods, a better insight of the interconnections between sea-level, regional glacial extent, and Northern Hemisphere marine and ice core climatic records.