scholarly journals Last Interglacial paleosols with Argic horizons in Upper Austria and Central Russia: Pedogenetic and paleoenvironmental inferences from comparison with the Holocene analogues

2013 ◽  
Vol 62 (1) ◽  
pp. 44-58 ◽  
Author(s):  
Sergey Sedov ◽  
Svetlana Sycheva ◽  
Teresa Pi ◽  
Jaime Díaz

Abstract. In vielen Löss-Paläoboden-Sequenzen der gemäßigten Breiten Europas ist das letzte Interglazial (dt.: Eem, russ.: Mikulino) durch einen Bt-Horizont (Argic horizon nach WRB) repräsentiert, der als pedologisches Resultat entsprechender bioklimatischer Bedingungen dieser Zeit gedeutet wird. Wir untersuchten mikromorphologische, physikalische/chemische (Gesamtelementzusammensetzung, Korngrößenverteilung und dithionitlösliches Eisen) und mineralogische Charakteristika im Profilabschnitt des Eem-Luvisols in Oberösterreich (Oberlaab) und des Mikulino-Albeluvisols in Zentralrussland (Alexandrov Grube nahe Kursk). Aus dem Vergleich der Paläoböden mit entsprechenden rezenten Böden ergeben sich paläoökologische und chronologische Schlussfolgerungen. Beide Profile zeigen eine Reihe von Charakteristika, die auf Verwitterung primärer Minerale und Tonminerale sowie Tonverlagerung und redoximorphe Prozesse hinweisen. Die Paläoböden zeigen jeweils eine weiter fortgeschrittene Entwicklung im Vergleich zu entsprechenden holozänen Böden, jedoch anhand unterschiedlicher pedogenetischer Merkmale. Der Eem-Luvisol in Oberösterreich weist ein höheres Maß an Tonverlagerung auf, was durch einen höheren Tongehalt und zahlreiche Toncutane im Bt-Horizont gezeigt wird. Der Mikulino-Albeluvisol in Zentralrussland ist stärker von Auswaschung und Stauwasser betroffen, was sich in tieferer und stärkerer Ansammlung von gebleichtem schluffigem Material und Tonverarmung zeigt. Wir nehmen an, dass das Ausgangsmaterial diese unterschiedliche Entwicklung hervorruft. Der russische Albeluvisol bildete sich auf Dnjepr-Löss, welcher im Vergleich zu den Riss-Lössen Oberösterreichs ärmer an leicht verwitterbaren Mineralen ist und daher eine geringere Kapazität Säure zu puffern sowie Ton neu zu bilden aufweist. Das fortgeschrittenere Entwicklungsstadium des letztinterglazialen Bodens im Vergleich zu holozänen Böden, die allgemein demselben Bodentyp entsprechen, spricht für eine längere Bodenentwicklungsphase, was mit paläobotanischen Ergebnissen in Einklang steht. Einerseits könnte der letztinterglaziale Paläoboden neben dem MIS 5e auch Teile des MIS 5d umfassen, andererseits könnte eine intensivere Paläobodenentwicklung durch das wärmere und feuchtere Paläoklima während der Interglazialphase des MIS 5e verursacht werden. Mehrere Phasen der Tonverlagerung, unterbrochen durch frostdynamische Strukturierung und Deformation sind im eemzeitlichen Bt-Horizont in Oberösterreich nachweisbar. Die noch weiter reichende Entwicklung könnte bis in noch jüngere Frühwürm-Interstadiale gereicht haben.

2011 ◽  
Vol 7 (2) ◽  
pp. 1195-1233 ◽  
Author(s):  
G. Trommer ◽  
M. Siccha ◽  
E. J. Rohling ◽  
K. Grant ◽  
M. T. J. van der Meer ◽  
...  

Abstract. This study investigates the response of Red Sea circulation to sea level and insolation changes during termination II and across the last interglacial, in comparison with termination I and the Holocene. Sediment cores from the central and northern part of the Red Sea were investigated by micropaleontological and geochemical proxies. The recovery of the planktonic foraminiferal fauna following high salinities during MIS 6 took place at similar sea-level stand (~50 m below present day), and with a similar species succession, as during termination I. This indicates a consistent sensitivity of the basin oceanography and the plankton ecology to sea-level forcing. Based on planktonic foraminifera, we find that increased water exchange with the Gulf of Aden especially occurred during the sea-level highstand of interglacial MIS 5e. From MIS 6 to the peak of MIS 5e, northern Red Sea SST increased from 21 °C to 25 °C, with about 3 °C of this increase taking place during termination II. Changes in planktonic foraminiferal assemblages indicate that the development of the Red Sea oceanography during MIS 5 was strongly determined by insolation and monsoon strength. The SW Monsoon summer circulation mode was enhanced during the termination, causing low productivity in northern central Red Sea core KL9, marked by high abundance of G. sacculifer, which – as in the Holocene – followed summer insolation. Core KL11 records the northern tip of the intruding intermediate water layer from the Gulf of Aden and its planktonic foraminifera fauna shows evidence for elevated productivity during the sea-level highstand in the southern central Red Sea. By the time of MIS 5 sea-level regression, elevated organic biomarker BIT values suggest denudation of soil organic matter into the Red Sea and high abundances of G. glutinata, and high reconstructed chlorophyll-a values, indicate an intensified NE Monsoon winter circulation mode. Our results imply that the amplitude of insolation fluctuations, and the resulting monsoon strength, strongly influence the Red Sea oceanography during sea-level highstands by regulating the intensity of water exchange with the Gulf of Aden. These processes are responsible for the observation that MIS 5e/d is characterized by higher primary productivity than the Holocene.


2017 ◽  
Author(s):  
Janina G. Stapel ◽  
Georg Schwamborn ◽  
Lutz Schirrmeister ◽  
Brian Horsfield ◽  
Kai Mangelsdorf

Abstract. Multiple permafrost cores from Bol'shoy Lyakhovsky Island in NE Siberia comprising deposits from Eemian to modern time are investigated to evaluate the stored potential of the freeze-locked organic matter (OM) to serve as substrate for the production of microbial greenhouse gases from thawing permafrost deposits. Deposits from Late Pleistocene glacial periods (comprising MIS 3 and MIS 4) possess an increased aliphatic character and a higher amount of potential substrates, and therefore higher OM quality in terms of biodegradation compared to interglacial deposits from the Eemian (MIS 5e) as well as from the Holocene (MIS 1). To assess the potential of the individual permafrost deposits to provide substrates for microbially induced greenhouse gas generation, concentrations of free and bound acetate as an excellent substrate for methanogenesis are used. The highest free (in pore water and segregated ice) and bound (bound to the organic matrix) acetate-substrate pools of the permafrost deposits are observed within the interstadial MIS 3 and stadial MIS 4 period deposits. In contrast, deposits from the last interglacial MIS 5e show only poor substrate pools. The Holocene deposits reveal a significant bound-acetate pool, representing at least a future substrate potential upon release during OM degradation. Biomarkers for past microbial communities (branched and isoprenoid GDGTs) show also highest abundance of past microbial communities during the MIS 3 and MIS 4 deposits, which indicates higher OM quality with respect to microbial degradation during time of deposition. On a broader perspective, Arctic warming will increase permafrost thaw and favour substrate availability from freeze-locked older permafrost deposits. Therefore, especially those deposits from MIS 3 and MIS 4 show a high potential for providing substrates relevant for methanogenesis.


2021 ◽  
Author(s):  
Lijuan Lu ◽  
Xufeng Zheng ◽  
Zhong Chen ◽  
Michael Weber ◽  
Victoria Peck ◽  
...  

Abstract The Antarctic Circumpolar Current (ACC) acts as a critical component to regulate the global thermohaline circulation and climate. However, active debate remains about the relative strength of ACC during current/past warm periods and underlying driving mechanisms. Here, we present sortable silt mean grain size records from the Scotia Sea to infer the ACC strength over the past 160 ka. The 22-ka cycles of sortable silt mean grain size suggest that the precession-driven contraction/expansion of Subtropical Jet dominates the migration of ACC fronts, and thus ACC speed and potential Atlantic Meridional Overturning Circulation stability. We find that the bottom flow speed during MIS 5e was over three times faster than the Holocene, with no apparent difference in ACC speed between the Holocene and the Last Glacial Maximum. We suggest that a southward shift of oceanic fronts of ~5° could cause the additional speed-up of ACC during MIS 5e. This could induce warmer water flowing in the ACC to approach and melt the Antarctica continental ice shelves, with corresponding effects on global sea level and the global climate.


2011 ◽  
Vol 7 (3) ◽  
pp. 941-955 ◽  
Author(s):  
G. Trommer ◽  
M. Siccha ◽  
E. J. Rohling ◽  
K. Grant ◽  
M. T. J. van der Meer ◽  
...  

Abstract. This study investigates the response of Red Sea circulation to sea level and insolation changes during termination II and across the last interglacial, in comparison with termination I and the Holocene. Sediment cores from the central and northern part of the Red Sea were investigated by micropaleontological and geochemical proxies. The recovery of the planktic foraminiferal fauna following high salinities during marine isotopic stage (MIS) 6 took place at similar sea-level stand (~50 m below present day), and with a similar species succession, as during termination I. This indicates a consistent sensitivity of the basin oceanography and the plankton ecology to sea-level forcing. Based on planktic foraminifera, we find that increased water exchange with the Gulf of Aden especially occurred during the sea-level highstand of interglacial MIS 5e. From MIS 6 to the peak of MIS 5e, northern Red Sea sea surface temperature (SST) increased from 21 °C to 25 °C, with about 3 °C of this increase taking place during termination II. Changes in planktic foraminiferal assemblages indicate that the development of the Red Sea oceanography during MIS 5 was strongly determined by insolation and monsoon strength. The SW Monsoon summer circulation mode was enhanced during the termination, causing low productivity in northern central Red Sea core KL9, marked by high abundance of G. sacculifer, which – as in the Holocene – followed summer insolation. Core KL11 records the northern tip of the intruding intermediate water layer from the Gulf of Aden and its planktic foraminifera fauna shows evidence for elevated productivity during the sea-level highstand in the southern central Red Sea. By the time of MIS 5 sea-level regression, elevated organic biomarker BIT values suggest denudation of soil organic matter into the Red Sea and high abundances of G. glutinata, and high reconstructed chlorophyll-a values, indicate an intensified NE Monsoon winter circulation mode. Our results imply that the amplitude of insolation fluctuations, and the resulting monsoon strength, strongly influence the Red Sea oceanography during sea-level highstands by regulating the intensity of water exchange with the Gulf of Aden. These processes are responsible for the observation that MIS 5e/d is characterized by higher primary productivity than the Holocene.


Nature ◽  
2021 ◽  
Vol 589 (7843) ◽  
pp. 548-553
Author(s):  
Samantha Bova ◽  
Yair Rosenthal ◽  
Zhengyu Liu ◽  
Shital P. Godad ◽  
Mi Yan

1981 ◽  
Vol 16 (3) ◽  
pp. 293-321 ◽  
Author(s):  
Calvin J. Heusser

AbstractPollen and spores in stratigraphic sections located between 40 and 42°S range in age from the Holocene, through much of the Llanquihue Glaciation, to the last interglaciation. Chronology of the stratigraphy derives from some 35 14C ages and the age relations of Llanquihue Drift and related deposits. Q-Mode, rotated, principal-components analysis of four key pollen records covering the last interglacial-glacial cycle resulted in four leading components: Nothofagus dombeyi type, Gramineae, Weinmannia-Fitzroya type, and Myrtaceae. Analysis emphasizes interaction between the first two components. Loadings of Gramineae during the interglaciation are high, unlike the Holocene; Weinmannia-Fitzroya-type loadings, prominent in the Holocene, are negligible during the interglaciation. N. dombeyi type is the primary component during Llanquihue Glaciation; it becomes modified by increases of Gramineae sometime after 31,000 and before 14,000 yr B.P. and of Myrtaceae later. The Myrtaceae with Weinmannia-Fitzroya type also registers some activity around 42,000 yr B.P. Fluctuations in the belt of westerly winds, reflecting changing meteorological conditions in polar latitudes, are suggested by these data. With the belt located farther south than it is today, interglacial climate was much drier and warmer than during the Holocene; more northerly displacement of the belt obtained when climate was colder during Llanquihue Glaciation. Evidence from comparable latitudes in the Southern Hemisphere points toward a synchrony of major climatic events indicating harmonious fluctuations in the position of the westerlies.


2021 ◽  
Vol 13 (1) ◽  
pp. 171-197
Author(s):  
Evan J. Gowan ◽  
Alessio Rovere ◽  
Deirdre D. Ryan ◽  
Sebastian Richiano ◽  
Alejandro Montes ◽  
...  

Abstract. Coastal southeast South America is one of the classic locations where there are robust, spatially extensive records of past high sea level. Sea-level proxies interpreted as last interglacial (Marine Isotope Stage 5e, MIS 5e) exist along the length of the Uruguayan and Argentinian coast with exceptional preservation especially in Patagonia. Many coastal deposits are correlated to MIS 5e solely because they form the next-highest terrace level above the Holocene highstand; however, dating control exists for some landforms from amino acid racemization, U∕Th (on molluscs), electron spin resonance (ESR), optically stimulated luminescence (OSL), infrared stimulated luminescence (IRSL), and radiocarbon dating (which provides minimum ages). As part of the World Atlas of Last Interglacial Shorelines (WALIS) database, we have compiled a total of 60 MIS 5 proxies attributed, with various degrees of precision, to MIS 5e. Of these, 48 are sea-level indicators, 11 are marine-limiting indicators (sea level above the elevation of the indicator), and 1 is terrestrial limiting (sea level below the elevation of the indicator). Limitations on the precision and accuracy of chronological controls and elevation measurements mean that most of these indicators are considered to be low quality. The database is available at https://doi.org/10.5281/zenodo.3991596 (Gowan et al., 2020).


2002 ◽  
Vol 58 (1) ◽  
pp. 32-35 ◽  
Author(s):  
George J. Kukla ◽  
Jacques-Louis de Beaulieu ◽  
Helena Svobodova ◽  
Valerie Andrieu-Ponel ◽  
Nicolas Thouveny ◽  
...  

AbstractEemian lake deposits in Grande Pile and Ribains, France, correlate with marine isotope substages (MIS) 5e and 5d as delimited in two pollen-bearing deep-sea cores off Portugal. The Eemian forests in France lasted for approximately 20 millennia, from at least 126,000 to ca. 107,000 yr B.P. Oscillatory climate deteriorations began about 115,000 yr ago. An intense cold spell affected the region approximately 110,000 yr ago.


2018 ◽  
Vol 130 (2) ◽  
pp. 71 ◽  
Author(s):  
Jim M. Bowler ◽  
David M. Price ◽  
John E. Sherwood ◽  
Stephen P. Carey

At Moyjil (Point Ritchie), a cliffed site at the mouth of the Hopkins River at Warrnambool, south-eastern Australia, an erosional disconformity of Last Interglacial age on both a rock stack and the adjacent headland represents a surface of possible human occupation. Shells of edible marine molluscs occur on the disconformity, together with a distinctive population of transported stones derived from a calcrete of MIS 7 age and bearing variable dark grey to near-black colouration suggestive of fire. Experimental fire produced similar thermal alteration of calcrete. A strong correlation exists between intensity and depth of dark staining on one hand and increased magnetic susceptibility on the other. Thermal luminescence analyses of blackened stones provide ages in the MIS 5e range, 100–130 ka, consistent with independent stratigraphic evidence and contemporaneous with the age of the surface on which they lie. The distribution of fire-darkened stones is inconsistent with wildfire effects. Two hearth-like features closely associated with the disconformity provide further indications of potential human agency. The data are consistent with the suggestion of human presence at Warrnambool during the Last Interglacial.


2002 ◽  
Vol 58 (1) ◽  
pp. 53-55 ◽  
Author(s):  
Polychronis C. Tzedakis ◽  
Michael R. Frogley ◽  
Timothy H.E. Heaton

AbstractA new astronomical calibration method for long pollen records from southern Europe is applied to the last interglacial interval of the Ioannina sequence, northwestern Greece. This shows that the last interglacial in this region, as defined by the presence of forest communities, lasted ca. 15,500 yr, from 127,300 to 111,800 yr B.P. Interglacial conditions developed within marine isotope substage (MIS) 5e and persisted into MIS 5d, lagging changes in global ice volume.


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