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Qingzhen Hao - One of the best experts on this subject based on the ideXlab platform.
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clay mineralogy of the stari slankamen serbia loess paleosol sequence during the last glacial cycle implications for dust provenance and interglacial climate
Quaternary Science Reviews, 2021Co-Authors: Qingzhen Hao, Slobodan B Markovic, Milivoj B. Gavrilov, Shuzhen Peng, Xinbo Gao, Long Han, Namier Namier, Wei Zhang, Rastko Markovic, Zhengtang GuoAbstract:Abstract Clay minerals in loess-paleosol sequences carry important information on dust source and the paleoenvironments of the areas of loess distribution. The loess-paleosol sequences in the Serbian part of the Carpathian Basin are among the most complete Quaternary terrestrial sedimentary sequences in Europe. However, relatively little is known about the origin and temporal variations of clay minerals in these deposits and their paleoclimatic implications. Here we present the results of high-resolution XRD clay mineral analysis of the Stari Slankamen loess-paleosol sequence through the last glacial cycle. The roughly constant composition of the clay minerals within the loess unit and most of the paleosol suggests that the clay minerals are of detrital origin and that pedogenic transformation has only occurred in the lower part of paleosol S1, which corresponds to the climatic optimum of Marine Isotope Stage (MIS) 5e. This provides a basis for addressing several important issues regarding the Carpathian Basin loess, including its provenance, glacial dust activity, and the interglacial climate. The smectite-rich characteristic of the glacial loess provides a diagnostic indicator for confirming local sources for the Carpathian Basin loess deposits, and that these sources made little contribution to the dust deposited in Greenland during the last glacial. The first application of illite crystallinity and the chlorite ratio to the Carpathian Basin loess-paleosol sequence suggests that they are more sensitive indicators than the clay mineral proxies previously used in European loess studies. The enhanced precipitation during MIS 5e indicated by the new proxies and the transformation of clay mineral potentially provide new insights into understanding the regional climatic response to future global warming.
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Patterns and timing of loess-paleosol transitions in Eurasia: Constraints for paleoclimate studies
Global and Planetary Change, 2018Co-Authors: Christian Zeeden, Ulrich Hambach, Igor Obreht, Qingzhen Hao, Daniel Veres, Frank Lehmkuhl, Milivoj B. Gavrilov, Slobodan B. Marković, Hemmo A. AbelsAbstract:Loess-paleosol sequences are the most extensive terrestrial paleoclimate records in Europe and Asia documenting atmospheric circulation patterns, vegetation, and sedimentary dynamics in response to glacial-interglacial cyclicity. Between the two sides of the Eurasian continent, differences may exist in response and response times to glacial changes and finding these is essential to understand the climate systems of the northern hemisphere. Therefore, assessment of common patterns and regional differences in loess-paleosol sequences (LPS) is vital, but remains, however, uncertain. Another key to interpret these records is to constrain the mechanisms responsible for the formation and preservation of paleosols and loess layers in these paleoclimate archives. This study therefore compares LPS magnetic susceptibility records as proxies for paleosol formation intensity for selected sites from the central Chinese Loess Plateau and the Carpathian Basin in Europe over the last 440 kyr. Inconsistencies and crucial issues concerning the timing, correlation and paleoclimate potential of selected Eurasian LPS are outlined. Our comparison of Eurasian LPS shows generally similar patterns of paleosol formation, while highlighting several crucial differences. Especially for paleosols developed around 200 and 300 ka, the reported timing of soil formation differs by up to 30 ka. In addition, a drying and cooling trend over the last 300 ka has been documented in Europe, with no such evidence in the Asian records. The comparison shows that there is still uncertainty in defining the chronostratigraphic framework for these records on glacial-interglacial time scales in the order of 5-30 kyr for the last 440 ka. We argue that the baseline of the magnetic susceptibility proxy in loess from the Carpathian Basin is the most striking difference between European LPS and the Chinese Loess Plateau. In our opinion, many of the current timing/age differences may be overcome once a comparable stratigraphic interpretation is achieved.
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the magnetic properties of loess and paleosol samples from the chinese loess plateau spanning the last 22 million years
Palaeogeography Palaeoclimatology Palaeoecology, 2008Co-Authors: Qingzhen Hao, Frank Oldfield, Jan Bloemendal, Zhengtang GuoAbstract:Abstract Magnetic measurements (susceptibility, isothermal and anhysteretic remanence, and quotients derived from these) are presented for a suite of loess and paleosol samples from sites on the Chinese Loess Plateau. The three sites, Xifeng, Dongwan and Qinan (QA-I), together span most of the last 22 million years. The results provide the first multi-parameter magnetic measurements from pre-Pleistocene loess/paleosol sequences that began accumulation in the early Miocene. Mass specific measurements have been corrected for carbonate concentrations which peak in the loess layers and range up to 57%. All the magnetic properties recorded indicate variability on both orbital and supra-orbital timescales. The changing magnetic properties allow the record to be divided into a sequence of eight sample groups that broadly parallel the main supra-orbital changes in magnetic susceptibility. The pre-Pleistocene parts of the record include intervals (mainly late Miocene and Pliocene) during which loess as well as paleosol layers are characterized by high values for properties such as frequency dependent susceptibility (χfd), usually associated with strong weathering. Most of the Miocene record prior to 8.5 Ma, with the exception of a brief interval from ca. 14.4 to 15.9 Ma, shows reduced values for indicators of pedogenic ferrimagnetic concentrations in both the loess and paleosol layers, as well as a low amplitude of variability between loess and paleosol values. The palaeoenvironmental implications of this part of the sequence are unclear since they hinge on the type of model of pedogenic magnetic mineral formation adopted. High-field remanence measurements indicate that the coercivity of the antiferromagnetic minerals represented declined progressively throughout the whole period in both the loess and the paleosol samples, though there is no unambiguous evidence for long-term diagenetic alteration of the magnetic properties on timescales beyond the orbital ones that drive the loess/paleosol alternations. The present results suggest caution in applying existing climofunctions based on magnetic susceptibility to deposits spanning the whole of the last 22 Ma.
Zhengtang Guo - One of the best experts on this subject based on the ideXlab platform.
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clay mineralogy of the stari slankamen serbia loess paleosol sequence during the last glacial cycle implications for dust provenance and interglacial climate
Quaternary Science Reviews, 2021Co-Authors: Qingzhen Hao, Slobodan B Markovic, Milivoj B. Gavrilov, Shuzhen Peng, Xinbo Gao, Long Han, Namier Namier, Wei Zhang, Rastko Markovic, Zhengtang GuoAbstract:Abstract Clay minerals in loess-paleosol sequences carry important information on dust source and the paleoenvironments of the areas of loess distribution. The loess-paleosol sequences in the Serbian part of the Carpathian Basin are among the most complete Quaternary terrestrial sedimentary sequences in Europe. However, relatively little is known about the origin and temporal variations of clay minerals in these deposits and their paleoclimatic implications. Here we present the results of high-resolution XRD clay mineral analysis of the Stari Slankamen loess-paleosol sequence through the last glacial cycle. The roughly constant composition of the clay minerals within the loess unit and most of the paleosol suggests that the clay minerals are of detrital origin and that pedogenic transformation has only occurred in the lower part of paleosol S1, which corresponds to the climatic optimum of Marine Isotope Stage (MIS) 5e. This provides a basis for addressing several important issues regarding the Carpathian Basin loess, including its provenance, glacial dust activity, and the interglacial climate. The smectite-rich characteristic of the glacial loess provides a diagnostic indicator for confirming local sources for the Carpathian Basin loess deposits, and that these sources made little contribution to the dust deposited in Greenland during the last glacial. The first application of illite crystallinity and the chlorite ratio to the Carpathian Basin loess-paleosol sequence suggests that they are more sensitive indicators than the clay mineral proxies previously used in European loess studies. The enhanced precipitation during MIS 5e indicated by the new proxies and the transformation of clay mineral potentially provide new insights into understanding the regional climatic response to future global warming.
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the magnetic properties of loess and paleosol samples from the chinese loess plateau spanning the last 22 million years
Palaeogeography Palaeoclimatology Palaeoecology, 2008Co-Authors: Qingzhen Hao, Frank Oldfield, Jan Bloemendal, Zhengtang GuoAbstract:Abstract Magnetic measurements (susceptibility, isothermal and anhysteretic remanence, and quotients derived from these) are presented for a suite of loess and paleosol samples from sites on the Chinese Loess Plateau. The three sites, Xifeng, Dongwan and Qinan (QA-I), together span most of the last 22 million years. The results provide the first multi-parameter magnetic measurements from pre-Pleistocene loess/paleosol sequences that began accumulation in the early Miocene. Mass specific measurements have been corrected for carbonate concentrations which peak in the loess layers and range up to 57%. All the magnetic properties recorded indicate variability on both orbital and supra-orbital timescales. The changing magnetic properties allow the record to be divided into a sequence of eight sample groups that broadly parallel the main supra-orbital changes in magnetic susceptibility. The pre-Pleistocene parts of the record include intervals (mainly late Miocene and Pliocene) during which loess as well as paleosol layers are characterized by high values for properties such as frequency dependent susceptibility (χfd), usually associated with strong weathering. Most of the Miocene record prior to 8.5 Ma, with the exception of a brief interval from ca. 14.4 to 15.9 Ma, shows reduced values for indicators of pedogenic ferrimagnetic concentrations in both the loess and paleosol layers, as well as a low amplitude of variability between loess and paleosol values. The palaeoenvironmental implications of this part of the sequence are unclear since they hinge on the type of model of pedogenic magnetic mineral formation adopted. High-field remanence measurements indicate that the coercivity of the antiferromagnetic minerals represented declined progressively throughout the whole period in both the loess and the paleosol samples, though there is no unambiguous evidence for long-term diagenetic alteration of the magnetic properties on timescales beyond the orbital ones that drive the loess/paleosol alternations. The present results suggest caution in applying existing climofunctions based on magnetic susceptibility to deposits spanning the whole of the last 22 Ma.
Kenneth A Farley - One of the best experts on this subject based on the ideXlab platform.
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evidence for 5 ma paleo exposure of an eocene miocene paleosol of the bohnerz formation switzerland
Earth and Planetary Science Letters, 2017Co-Authors: Florian Hofmann, Bettina Reichenbacher, Kenneth A FarleyAbstract:We obtained (U–Th)/He formation ages and cosmogenic ^3He concentrations for pisoliths from a paleosol of the Bohnerz Formation (Siderolithic) of Central Europe. The paleosol is exposed in the Almenbuhl quarry near Lohn, Canton Schaffhausen, Switzerland. The paleosol consists of red clay of 3–4 m thickness developed on deeply weathered Jurassic limestone and overlain by Early Miocene conglomerates. The (U–Th)/He formation ages of the pisoliths are between 50 Ma and 8 Ma, with most ages being older than 17 Ma. There is a sharp decline in the frequency of ages at the time of burial of the paleosol at 17 Ma. These ages are inconsistent with the previous assumption that the Bohnerz Formation formed in a Cretaceous to Early Eocene laterite in a tropical climate. We propose that the Bohnerz Formation more closely resembles Terra Rossa soils, which do not require a tropical climate to form. The ^3He concentration in the pisoliths is roughly constant with depth throughout the paleosol at 300 Matoms/g. We interpret this as the result of soil convection during cosmic ray exposure. The minimum exposure duration at the surface of the paleosol is ∼5 Ma. A simple model of soil convection shows that the true exposure duration of the paleosol is approximately 10–20 Ma. These results indicate that the clay soils of the Bohnerz formation were continuously exposed at the surface for millions of years. Since the paleosol was covered by conglomerate since 17 Ma, the ^3He measured here was produced by cosmic ray exposure before burial. Cosmogenic ^3He concentrations measured in fine-grained soil iron-oxides (<1 μm) are similar to those measured in pisoliths. This might indicate that fine-grained iron-oxides are retentive to helium and might be used for studying the formation and cosmic ray exposure of modern soils and paleosols.
Alessandro Amorosi - One of the best experts on this subject based on the ideXlab platform.
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sequence stratigraphy and late quaternary paleoenvironmental evolution of the northern adriatic coastal plain italy
Palaeogeography Palaeoclimatology Palaeoecology, 2017Co-Authors: Bruno Campo, Alessandro Amorosi, Stefano Claudio VaianiAbstract:Abstract Integrated sedimentological and micropaleontological data were used for the construction of a 93 km-long stratigraphic cross-section parallel to the modern Adriatic shoreline (northern Italy). The stratigraphic panel shows, for the first time, along-strike changes in facies architecture. The Late Pleistocene succession consists of well-drained floodplain deposits. Multi-storey fluvial-channel bodies, ~ 20 m thick, are correlative with a paleosol that formed in response to sea-level fall and river incision at the onset of the Last Glacial Maximum (MIS 3/2). Another paleosol (12.5–10 kyr cal BP), associated with the Younger Dryas cold event, marks the transition to overlying Holocene coastal facies. In terms of sequence stratigraphy, the lower paleosol represents the sequence boundary and the correlative, amalgamated channel-belt deposits form the lowstand systems tract. The transgressive surface coincides with a weakly-developed paleosol (18.5–16 kyr cal BP) that marks a major phase of channel abandonment induced by early sea-level rise. The Younger Dryas paleosol allows subdivision of the transgressive systems tract (TST) into lower and upper TST. The lower TST, well developed in the south, is characterized by thin poorly-drained floodplain deposits; the upper TST, showing vertical transition to coastal and shallow-marine clays, has diagnostic ‘marine’ signature, and is laterally continuous, with no significant thickness changes. The maximum flooding surface marks the turnaround from a deepening-upward to shallowing-upward trend. The highstand systems tract includes a prograding succession of prodelta clays and overlying delta-front/beach-ridge sands, which form a laterally continuous sedimentary body. Nearshore sands accumulated in prograding delta systems characterized by wave-dominated, arcuate geometries, with transition to laterally continuous strandplains.
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paleosol architecture of a late quaternary basin margin sequence and its implications for high resolution non marine sequence stratigraphy
Global and Planetary Change, 2014Co-Authors: Alessandro Amorosi, Luigi Bruno, Veronica Rossi, P Severi, Irka HajdasAbstract:Abstract Paleosol stratigraphy, a technique commonly applied in basin–margin settings to depict cyclic alluvial architecture on time scales of 10–100 ky, can be consistent with regional accommodation trends at even higher temporal resolution (1–10 ky), having strong implications for the sequence stratigraphy of late Quaternary, non-marine deposits. Three closely-spaced late Pleistocene paleosols (P1–P3), dating back approximately to 42–39, 35–31, and 29–26 cal kyr BP, respectively, form prominent stratigraphic markers across a lithologically homogeneous interfluve succession in the subsurface of Bologna, close to the Apenninic foothills. These paleosols are weakly developed (Inceptisols) and can be tracked continuously for 6 km across the triangle-shaped interchannel zone between two gravel/sand-filled channel systems (Reno and Savena rivers). In particular, the thickest paleosol (P3) is a distinctive stiff horizon that can be traced into laterally extensive, erosional-based fluvial bodies. We infer the correlation between (P3) soil development (and channel downcutting) and the final stage of the stepwise Late Pleistocene sea-level fall that culminated at the marine isotope stage 3/2 transition around 29 cal kyr BP (low accommodation systems tract). A fourth laterally extensive Inceptisol, encompassing the Pleistocene–Holocene boundary (PH), represents the major phase of soil development since the Last Glacial Maximum and is inferred to be related to channel entrenchment at the onset of the Younger Dryas. With the exception of the Iron Age-Roman paleosol, which reflects a predominantly anthropogenic control, the Holocene paleosols are laterally discontinuous and invariably more immature (Entisols) than their Pleistocene counterparts. This trend of decreasing paleosol development (and correlatability) upsection is interpreted to reflect increasing (transgressive-equivalent) accommodation during sea-level rise, thus confirming the possible extension of models used to interpret the ancient rock record to short-term depositional cycles.
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Paleosol architecture of a late Quaternary basin–margin sequence and its implications for high-resolution, non-marine sequence stratigraphy
2014Co-Authors: Alessandro Amorosi, Luigi Bruno, Veronica Rossi, P Severi, Irka HajdasAbstract:Paleosol stratigraphy, a technique commonly applied in basin-margin settings to depict cyclic alluvial architecture on time scales of 10-100. ky, can be consistent with regional accommodation trends at even higher temporal resolution (1-10. ky), having strong implications for the sequence stratigraphy of late Quaternary, non-marine deposits. Three closely-spaced late Pleistocene paleosols (P1-P3), dating back approximately to 42-39, 35-31, and 29-26. cal. kyr BP, respectively, form prominent stratigraphic markers across a lithologically homogeneous interfluve succession in the subsurface of Bologna, close to the Apenninic foothills. These paleosols are weakly developed (Inceptisols) and can be tracked continuously for 6. km across the triangle-shaped interchannel zone between two gravel/sand-filled channel systems (Reno and Savena rivers). In particular, the thickest paleosol (P3) is a distinctive stiff horizon that can be traced into laterally extensive, erosional-based fluvial bodies. We infer the correlation between (P3) soil development (and channel downcutting) and the final stage of the stepwise Late Pleistocene sea-level fall that culminated at the marine isotope stage 3/2 transition around 29. cal. kyr BP (low accommodation systems tract). A fourth laterally extensive Inceptisol, encompassing the Pleistocene-Holocene boundary (PH), represents the major phase of soil development since the Last Glacial Maximum and is inferred to be related to channel entrenchment at the onset of the Younger Dryas. With the exception of the Iron Age-Roman paleosol, which reflects a predominantly anthropogenic control, the Holocene paleosols are laterally discontinuous and invariably more immature (Entisols) than their Pleistocene counterparts. This trend of decreasing paleosol development (and correlatability) upsection is interpreted to reflect increasing (transgressive-equivalent) accommodation during sea-level rise, thus confirming the possible extension of models used to interpret the ancient rock record to short-term depositional cycles
Florian Hofmann - One of the best experts on this subject based on the ideXlab platform.
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evidence for 5 ma paleo exposure of an eocene miocene paleosol of the bohnerz formation switzerland
Earth and Planetary Science Letters, 2017Co-Authors: Florian Hofmann, Bettina Reichenbacher, Kenneth A FarleyAbstract:We obtained (U–Th)/He formation ages and cosmogenic ^3He concentrations for pisoliths from a paleosol of the Bohnerz Formation (Siderolithic) of Central Europe. The paleosol is exposed in the Almenbuhl quarry near Lohn, Canton Schaffhausen, Switzerland. The paleosol consists of red clay of 3–4 m thickness developed on deeply weathered Jurassic limestone and overlain by Early Miocene conglomerates. The (U–Th)/He formation ages of the pisoliths are between 50 Ma and 8 Ma, with most ages being older than 17 Ma. There is a sharp decline in the frequency of ages at the time of burial of the paleosol at 17 Ma. These ages are inconsistent with the previous assumption that the Bohnerz Formation formed in a Cretaceous to Early Eocene laterite in a tropical climate. We propose that the Bohnerz Formation more closely resembles Terra Rossa soils, which do not require a tropical climate to form. The ^3He concentration in the pisoliths is roughly constant with depth throughout the paleosol at 300 Matoms/g. We interpret this as the result of soil convection during cosmic ray exposure. The minimum exposure duration at the surface of the paleosol is ∼5 Ma. A simple model of soil convection shows that the true exposure duration of the paleosol is approximately 10–20 Ma. These results indicate that the clay soils of the Bohnerz formation were continuously exposed at the surface for millions of years. Since the paleosol was covered by conglomerate since 17 Ma, the ^3He measured here was produced by cosmic ray exposure before burial. Cosmogenic ^3He concentrations measured in fine-grained soil iron-oxides (<1 μm) are similar to those measured in pisoliths. This might indicate that fine-grained iron-oxides are retentive to helium and might be used for studying the formation and cosmic ray exposure of modern soils and paleosols.