Source-to-sink system in the south bank of Qinghai Lake

2018 ◽  
Vol 6 (1) ◽  
pp. T109-T126 ◽  
Author(s):  
Wenmao Xu ◽  
Zaixing Jiang ◽  
Ji Chen ◽  
Chao Liu ◽  
Lingyu Dong
Keyword(s):  
Late Pleistocene ◽  
Lake Level ◽  
Global Climate ◽  
Field Investigation ◽  
Qinghai Lake ◽  
Alluvial Fans ◽  
The South ◽  
Lake Shore ◽  
Source To Sink ◽  
Lake Basins

In the south bank of Qinghai Lake, numerous alluvial fans and coastal deposits have been formed. In terms of their developmental positions and relationships, the denudation system, depositional system, and transportation system consist of source-to-sink systems. Based on the field-investigation evidence and literature survey, it was confirmed that the developmental processes of these “source-to-sink” systems can be divided into three stages: the Early-Late Pleistocene stage, from 39 to 23 ka BP; Late Pleistocene-Early Holocene stage, from 39 to 10.7 ka BP; and modern stage. At the present time, these stages can still be identified as three levels of lake shore terraces. In the Late Pleistocene, the source-to-sink system indicates that the lake level was high, supply of clasts was sufficient, fan deltas had formed, and the lakeside plain continued to develop. At the end of the Late Pleistocene, with the sudden changes in global climate, the climate was dry and cold, and the lake level fell. At this time, the source-to-sink system showed that lake level was relatively low, supply of clasts was reduced, and transportation distance was longer; ancient sediments started to recycle in this system. Until modern times, alluvial fans in the south bank of Qinghai Lake have only rarely been developed, and the supply of clasts is primarily derived from the recirculation of paleo-shore sediments. Meanwhile, a large amount of sandy gravel beaches developed along the lake shore. By studying the multistage source-to-sink systems around modern lakes, the characteristics of the system in lake basins are enriched and provide an important analogy for researches of ancient lake basins.

ENCODING PERIODIC TECTONIC FORCINGS IN THE STRATIGRAPHY AND GEOMORPHOLOGY OF A FAULT-CONTROLLED LATE PLEISTOCENE SOURCE-TO-SINK SYSTEM

2020 ◽  
Author(s):  
Francesco Pavano ◽  
◽  
Nathan J. Lyons ◽  
Benjamin Bliss ◽  
Sean Gallen ◽  
...  
Keyword(s):  
Late Pleistocene ◽  
Source To Sink

scholarly journals Meridional changes in the South Atlantic Subtropical Gyre during Heinrich Stadials

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tainã M. L. Pinho ◽  
Cristiano M. Chiessi ◽  
Rodrigo C. Portilho-Ramos ◽  
Marília C. Campos ◽  
Stefano Crivellari ◽  
...  
Keyword(s):  
Global Climate ◽  
South Atlantic ◽  
Subtropical Gyre ◽  
Climate System ◽  
The South ◽  
Foraminiferal Species ◽  
Ocean Gyres ◽  
Long Term Monitoring ◽  
Term Monitoring

AbstractSubtropical ocean gyres play a key role in modulating the global climate system redistributing energy between low and high latitudes. A poleward displacement of the subtropical gyres has been observed over the last decades, but the lack of long-term monitoring data hinders an in-depth understanding of their dynamics. Paleoceanographic records offer the opportunity to identify meridional changes in the subtropical gyres and investigate their consequences to the climate system. Here we use the abundance of planktonic foraminiferal species Globorotalia truncatulinodes from a sediment core collected at the northernmost boundary of the South Atlantic Subtropical Gyre (SASG) together with a previously published record of the same species from the southernmost boundary of the SASG to reconstruct meridional fluctuations of the SASG over last ca. 70 kyr. Our findings indicate southward displacements of the SASG during Heinrich Stadials (HS) 6-4 and HS1, and a contraction of the SASG during HS3 and HS2. During HS6-4 and HS1, the SASG southward displacements likely boosted the transfer of heat to the Southern Ocean, ultimately strengthening deep-water upwelling and CO2 release to the atmosphere. We hypothesize that the ongoing SASG poleward displacement may further increase oceanic CO2 release.

Eolian and fluvial sedimentation in the southwestern Sinai Mountains, Egypt: a record of flash floods during the late Pleistocene

2012 ◽  
Vol 44 (2) ◽  
pp. 281-299
Author(s):  
Jörg Völkel ◽  
Jörg Grunert ◽  
Matthias Leopold ◽  
Kerstin Hürkamp ◽  
Juliane Huber ◽  
...  
Keyword(s):  
Late Pleistocene ◽  
Arid Environment ◽  
Alluvial Fan ◽  
Luminescence Dating ◽  
Alluvial Fans ◽  
Extreme Floods ◽  
Optically Stimulated Luminescence Dating ◽  
Fluvial Sedimentation ◽  
Southwestern Sinai ◽  
The Last Glacial

Wadis emerging from the southwestern Sinai Mountains (Egypt) westwards to the Gulf of Suez are filled by >40 m thick late Pleistocene sediments, which have been subsequently incised to bedrock after the Last Glacial Maximum (LGM). Sedimentation and erosion resulted from changes in the basin's hydrological conditions caused by climate variations. Sediment characteristics indicate distinct processes ranging from high to low energy flow regimes. Airborne material is important as a sediment source. The fills are associated with alluvial fans at wadi mouths at the mountain fronts. Each alluvial fan is associated and physically correlated with the respective sediment fill in its contributing wadi. The alluvial fans have steep gradients and are only a few kilometers long or wide. The alluvial fans converge as they emerge from the adjacent valleys. According to optically stimulated luminescence dating, the initial sediment has an age of ∼45 ka and the sedimentation ends ∼19 ka, i.e., happened mainly during marine isotope stage (MIS) 3 and early MIS 2 formation and initial incision sometime during LGM. As the delivery of sediments in such a hyper-arid environment is by extreme floods, this study indicates an interval of intense fluvial activity, probably related to increased frequency of extreme floods in Southern Sinai. This potentially indicates a paleoclimatic change in this hyper-arid environment.

Impact of extreme hydrological perturbation on sediment distribution from source to sink, PETM, Spain.

2021 ◽  
Author(s):  
Marine Prieur ◽  
Alexander C. Whittaker ◽  
Fritz Schlunegger ◽  
Tor O. Sømme ◽  
Jean Braun ◽  
...  
Keyword(s):  
Climate Change ◽  
Climate Adaptation ◽  
Global Climate ◽  
Depositional Environments ◽  
Lead Author ◽  
Current Increase ◽  
Sediment Distribution ◽  
Current Climate ◽  
Source To Sink ◽  
The Impact

<p>Sedimentary dynamics and fluxes are influenced by both autogenic and allogenic forcings. A better understanding of the evolution of sedimentary systems through time and space requires us to decipher, and therefore to characterise, the impact of each of these on the Earth’s landscape. Given the current increase in the concentration of atmospheric carbon, studying the impact of rapid and global climate changes is of particular importance at the present time. Such events have been clearly defined in the geologic record. Among them, the Paleocene-Eocene Thermal Maximum (PETM) has been extensively studied worldwide and represents a possible analogue of the rapid current climate warming.</p><p>The present project focuses on the Southern Pyrenees (Spain) where excellent exposures of the Paleocene-Eocene interval span a large range of depositional environments from continental to deep-marine. These conditions allow us to collect data along the whole depositional system in order to document changes in sediment fluxes and paleohydraulic conditions. Because hydrological conditions have an impact on sediment transport through hydrodynamics, paleoflow reconstructions can shed light on changes in sediment dynamics. This information is reconstructed from the statistical distributions of channel morphologies, characteristic system dimensions including bankfull channel depth and width, and grain-sizes.</p><p>With this approach, our aim is to provide both qualitative and quantitative assessments of the magnitude and extent of the perturbation of sedimentary fluxes along an entire source-to-sink system during an episode of extreme climate change. This will lead to a better understanding of the impact of abrupt climate change on earth surface systems in mid-latitudinal areas, with possible implications for current climate adaptation policy.</p><p>This research is carried out in the scope of the lead author’s PhD project and is part of the S2S-FUTURE European Marie Skłodowska-Curie ITN (Grant Agreement No 860383).</p>

The Characteristics of Palaeogeomorphology in Ek1 and the Lower Part of Es4 of the Paleogene in Dongying Depression and its Significance to Petroleum Geology

2012 ◽  
Vol 524-527 ◽  
pp. 226-230
Author(s):  
Li An Liu ◽  
Jian Bo Han
Keyword(s):  
Petroleum Geology ◽  
Alluvial Fans ◽  
The South ◽  
Research Results ◽  
Northern Basin ◽  
Dongying Depression ◽  
Contour Graph ◽  
Shahejie Formation ◽  
Fourth Member

By using the data of drilling and logging and other materials, the contour graph of the thickness of the remnant strata can be worked out. After the compaction restoration of the graph, the original sedimentary thickness of the First Member of Kongdian Formation(Ek1) and the Lower Part of the Fourth Member of Shahejie Formation ( lower Es4) can be obtained and their palaeogeomorphology can be reconstructed. The research results show that palaeogeomorphology has an obvious control on the sedimentary systems of Ek1 and lower Es4. In the areas with higher mountains and steeper slopes in the northern basin, there mainly develop nearshore subaqueous fans while in the south of the basin, there mostly develop alluvial fans.

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