scholarly journals The Quaternary Climatic and Tectonic Development of the Murat River Valley (Muş Basin, Eastern Turkey) as Recorded by Fluvial Deposits Dated by Optically Stimulated Luminescence

Quaternary ◽  
2021 ◽  
Vol 4 (3) ◽  
pp. 29
Author(s):  
Nurcan Avşin ◽  
Mehmet Korhan Erturaç ◽  
Eren Şahiner ◽  
Tuncer Demir
Keyword(s):  
Optically Stimulated Luminescence ◽  
Fluvial System ◽  
Middle Section ◽  
Alluvial Terrace ◽  
Last Glacial Period ◽  
Fluvial Systems ◽  
Tectonic Development ◽  
River Deposits ◽  
East Anatolia ◽  
The Last Glacial

The paper describes climatic and tectonic effects on fluvial processes of East Anatolia. This study from the Muş Basin contains three alluvial terrace levels (T3-T1) ranging from 30–35 m to 3–5 m above the present Murat River in its middle section. In order to provide a chronology for the evaluation of the significant, effects of climatic changes and tectonic uplift, we used optically stimulated luminescence (OSL) dating of the river deposits of the youngest (T3) and medium terrace (T2). The ages from these terrace deposits show that the T3 has formed approximately 6.5 ka ago, i.e., during the last part of the Holocene (MIS 1) and T2 has formed nearly 25 ka ago, i.e., during MIS 2 at the ending of the last glacial period. According to these results, it appears that the Murat River established its terrace sequences both in cold and warm periods. The variations in climate oriented fluvial evolution between the East Anatolia fluvial system and the temperate-periglacial fluvial systems in Europe may be the conclusion of different vegetation cover and melting thicker snow coverings in cold periods.

scholarly journals Chronology and provenance of last-glacial (peoria) loess in western iowa and paleoclimatic implications

2013 ◽  
Vol 80 (3) ◽  
pp. 468-481 ◽  
Author(s):  
Daniel R. Muhs ◽  
E. Arthur Bettis III ◽  
Helen M. Roberts ◽  
Stephen S. Harlan ◽  
James B. Paces ◽  
...  
Keyword(s):  
Grain Size ◽  
Missouri River ◽  
Optically Stimulated Luminescence ◽  
Laurentide Ice Sheet ◽  
Glacial Period ◽  
Accumulation Rates ◽  
Last Glacial Period ◽  
Last Glacial ◽  
The Earth ◽  
The Last Glacial

Geologic archives show that the Earth was dustier during the last glacial period. One model suggests that increased gustiness (stronger, more frequent winds) enhanced dustiness. We tested this at Loveland, Iowa, one of the thickest deposits of last-glacial-age (Peoria) loess in the world. Based on K/Rb and Ba/Rb, loess was derived not only from glaciogenic sources of the Missouri River, but also distal loess from non-glacial sources in Nebraska. Optically stimulated luminescence (OSL) ages provide the first detailed chronology of Peoria Loess at Loveland. Deposition began after ~ 27 ka and continued until ~ 17 ka. OSL ages also indicate that mass accumulation rates (MARs) of loess were not constant. MARs were highest and grain size was coarsest during the time of middle Peoria Loess accretion, ~ 23 ka, when ~ 10 m of loess accumulated in no more than ~ 2000 yr and possibly much less. The timing of coarsest grain size and highest MAR, indicating strongest winds, coincides with a summer-insolation minimum at high latitudes in North America and the maximum southward extent of the Laurentide ice sheet. These observations suggest that increased dustiness during the last glacial period was driven largely by enhanced gustiness, forced by a steepened meridional temperature gradient.

scholarly journals Post-depositional manganese mobilization during the last glacial period in sediments of the eastern Clarion-Clipperton Zone, Pacific Ocean

2020 ◽  
Vol 532 ◽  
pp. 116012 ◽  
Author(s):  
Jessica B. Volz ◽  
Bo Liu ◽  
Male Köster ◽  
Susann Henkel ◽  
Andrea Koschinsky ◽  
...  
Keyword(s):  
Pacific Ocean ◽  
Glacial Period ◽  
Last Glacial Period ◽  
Last Glacial ◽  
The Last Glacial

scholarly journals <i>δ</i><sup>13</sup>C decreases in the upper western South Atlantic during Heinrich Stadials 3 and 2

2017 ◽  
Vol 13 (4) ◽  
pp. 345-358 ◽  
Author(s):  
Marília C. Campos ◽  
Cristiano M. Chiessi ◽  
Ines Voigt ◽  
Alberto R. Piola ◽  
Henning Kuhnert ◽  
...  
Keyword(s):  
Climate Change ◽  
South Atlantic ◽  
Meridional Overturning Circulation ◽  
Glacial Period ◽  
Last Deglaciation ◽  
Last Glacial Period ◽  
Last Glacial ◽  
Change Events ◽  
The Last Glacial ◽  
Millennial Scale

Abstract. Abrupt millennial-scale climate change events of the last deglaciation (i.e. Heinrich Stadial 1 and the Younger Dryas) were accompanied by marked increases in atmospheric CO2 (CO2atm) and decreases in its stable carbon isotopic ratios (δ13C), i.e. δ13CO2atm, presumably due to outgassing from the ocean. However, information on the preceding Heinrich Stadials during the last glacial period is scarce. Here we present δ13C records from two species of planktonic foraminifera from the western South Atlantic that reveal major decreases (up to 1 ‰) during Heinrich Stadials 3 and 2. These δ13C decreases are most likely related to millennial-scale periods of weakening of the Atlantic meridional overturning circulation and the consequent increase (decrease) in CO2atm (δ13CO2atm). We hypothesise two mechanisms that could account for the decreases observed in our records, namely strengthening of Southern Ocean deep-water ventilation and weakening of the biological pump. Additionally, we suggest that air–sea gas exchange could have contributed to the observed δ13C decreases. Together with other lines of evidence, our data are consistent with the hypothesis that the CO2 added to the atmosphere during abrupt millennial-scale climate change events of the last glacial period also originated in the ocean and reached the atmosphere by outgassing. The temporal evolution of δ13C during Heinrich Stadials 3 and 2 in our records is characterized by two relative minima separated by a relative maximum. This w structure is also found in North Atlantic and South American records, further suggesting that such a structure is a pervasive feature of Heinrich Stadial 2 and, possibly, also Heinrich Stadial 3.

Global population divergence of the sea star Hippasteria phrygiana corresponds to the onset of the last glacial period of the Pleistocene

2013 ◽  
Vol 160 (5) ◽  
pp. 1285-1296 ◽  
Author(s):  
D. W. Foltz ◽  
S. D. Fatland ◽  
M. Eléaume ◽  
K. Markello ◽  
K. L. Howell ◽  
...  
Keyword(s):  
Population Divergence ◽  
Glacial Period ◽  
Sea Star ◽  
Last Glacial Period ◽  
Last Glacial ◽  
Global Population ◽  
The Last Glacial

scholarly journals South Pole glacial climate reconstruction from multi-borehole laser particulate stratigraphy

2013 ◽  
Vol 59 (218) ◽  
pp. 1117-1128 ◽  
Author(s):  
Keyword(s):  
Particle Physics ◽  
Volcanic Ash ◽  
Ice Core ◽  
Hot Water ◽  
Radiometric Dating ◽  
South Pole ◽  
Last Glacial Period ◽  
Annual Layer ◽  
Paleoclimate Records ◽  
The Last Glacial

AbstractThe IceCube Neutrino Observatory and its prototype, AMANDA, were built in South Pole ice, using powerful hot-water drills to cleanly bore >100 holes to depths up to 2500 m. The construction of these particle physics detectors provided a unique opportunity to examine the deep ice sheet using a variety of novel techniques. We made high-resolution particulate profiles with a laser dust logger in eight of the boreholes during detector commissioning between 2004 and 2010. The South Pole laser logs are among the most clearly resolved measurements of Antarctic dust strata during the last glacial period and can be used to reconstruct paleoclimate records in exceptional detail. Here we use manual and algorithmic matching to synthesize our South Pole measurements with ice-core and logging data from Dome C, East Antarctica. We derive impurity concentration, precision chronology, annual-layer thickness, local spatial variability, and identify several widespread volcanic ash depositions useful for dating. We also examine the interval around ∼74 ka recently isolated with radiometric dating to bracket the Toba (Sumatra) supereruption.

scholarly journals Deep Ocean storage of heat and CO2 in the Fram Strait, Arctic Ocean during the last glacial period

2021 ◽  
Author(s):  
Mohamed M. Ezat ◽  
Tine L. Rasmussen ◽  
Mathis P. Hain ◽  
Mervyn Greaves ◽  
James W B Rae ◽  
...  
Keyword(s):  
Arctic Ocean ◽  
Deep Ocean ◽  
Fram Strait ◽  
Glacial Period ◽  
Last Glacial Period ◽  
Last Glacial ◽  
The Last Glacial
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