Provenance of freshwater pulses in the Gulf of Mexico during the last deglaciation

2010 ◽  
Vol 74 (2) ◽  
pp. 235-245 ◽  
Author(s):  
T. Sionneau ◽  
V. Bout-Roumazeilles ◽  
B.P. Flower ◽  
A. Bory ◽  
N. Tribovillard ◽  
...  
Keyword(s):  
Gulf Of Mexico ◽  
Clay Mineralogy ◽  
Mineralogical Composition ◽  
Last Deglaciation ◽  
Distribution Maps ◽  
Drainage Patterns ◽  
Southeastern Margin ◽  
Southwestern Margin ◽  
The Last Deglaciation ◽  
Orca Basin

AbstractDuring the last deglaciation, the decaying Laurentide Ice Sheet (LIS) delivered huge volumes of meltwater toward the Gulf of Mexico. The present investigation of clay mineralogy and grain-size characteristics of terrigenous sediments deposited in the Orca Basin (Gulf of Mexico) offers a unique opportunity to link the marine record of these meltwater floods with the reconstructed continental glacial history and the modeled drainage patterns. Five peculiar sedimentary levels, characterized by high smectite content and low CaCO3 content, were identified and occurred simultaneously with major meltwater floods. According to recently published clay mineral distribution maps for North America, these results help to pinpoint the southwestern margin of the LIS as a main contributor to most of the meltwater discharges. In addition, the peculiar mineralogical composition (illite and chlorite-rich) of the sediments characterizing the meltwater episode associated with Heinrich event 1 suggests a provenance from the Great Lakes area, supporting the interpretation of destabilization of the LIS southeastern margin during this event. Decreased terrigenous contribution associated with changing provenance of sediments after 12.9 cal ka BP suggests strong modifications of the continental hydrography in relation to Lake Agassiz history and changes in the morphology of Mississippi delta due to rising sea level.

scholarly journals Landscape Dynamics in the Caspian Lowlands Since the Last Deglaciation Reconstructed From the Pedosedimentary Sequence of Srednaya Akhtuba, Southern Russia

Geosciences ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 492 ◽  
Author(s):  
Marina Lebedeva ◽  
Alexander Makeev ◽  
Alexey Rusakov ◽  
Tatiana Romanis ◽  
Tamara Yanina ◽  
...  
Keyword(s):  
Clay Mineralogy ◽  
Fine Sand ◽  
Middle Part ◽  
Source Material ◽  
Last Deglaciation ◽  
Soil Horizons ◽  
Aeolian Transport ◽  
Southern Russia ◽  
Buried Soil ◽  
The Last Deglaciation

Surface Kastanozem of the Lower Volga area was first studied as a part of the pedocomplex, with the lower part (148–160 cm) formed in Early Khvalynian Chocolate clays (13–15 ka), the middle part (100–148 cm) in a mixed clay-loess sediment sand, and the upper part (0–100 cm) in loess. This resulted from local aeolian transport, with the source material derived from the rewinding of marine sediments. They are enriched in aggregates of Chocolate clays and glauconitic grains of a fine sand-course silt size and have similar contents of clay minerals. The high salinity of similar types evidences marine genesis for both Chocolate clays and source material for loess sediments. Clay fragments of a sand and silt size are responsible for the heavy texture and high gypsum content of loess. The study of soils with the focus on micromorphology and clay mineralogy allows the identification of the complex character of a shift from marine to sub-areal sedimentation. This shift was accompanied by short breaks in sedimentation, allowing the development of synlithogenic soil horizons of Late Khvalynian, after-Khvanynian, and Boreal time. The features of shallowly buried soil horizons confirm increased aridity after the last deglaciation. Surface Calcic Kastanozem is a full Holocene soil reflecting the present environment. However, it is deeply influenced by shallow buried soil horizons and Chocolate clays.

scholarly journals Changes in detrital sediment supply to the central Yellow Sea since the last deglaciation

Ocean Science ◽  
2020 ◽  
Vol 16 (5) ◽  
pp. 1247-1259
Author(s):  
Hyo Jin Koo ◽  
Hyen Goo Cho
Keyword(s):  
Grain Size ◽  
Yellow Sea ◽  
Clay Mineralogy ◽  
Sediment Supply ◽  
The Yellow Sea ◽  
Sediment Provenance ◽  
Last Deglaciation ◽  
Yellow Sea Warm Current ◽  
The Last Deglaciation ◽  
Coarse Sediments

Abstract. The sediment supply to the central Yellow Sea since the last deglaciation was uncovered through clay mineralogy and geochemical analysis of core 11YS-PCL14 in the Central Yellow Sea Mud (CYSM). The core can be divided into four units based on the various proxies, such as grain size, clay mineralogy, geochemistry, and Sr and Nd isotopes: Unit 4 (700–520 cm; 15.5–14.8 ka), Unit 3 (520–310 cm; 14.8–12.8 ka), Unit 2 (310–130 cm; 12.8–8.8 ka), and Unit 1 (130–0 cm; <8.8 ka). Unit 2 is subdivided into two subunits, Unit 2-2 (310–210 cm; 12.8–10.5 ka) and Unit 2-1 (210–130 cm; 10.5–8.8 ka), according to smectite content. Comparison of the clay mineral compositions, rare earth elements, and εNd indicate distinct provenance shifts in core 11YS-PCL14. Moreover, the integration of clay mineralogical and geochemical indices show different origins according to particle size. During the late last deglaciation (Units 3 and 4, 15.5–12.8 ka), Unit 4 sediments originated from all potential provenance rivers, such as the Huanghe, Changjiang, and western Korean rivers, while the source of coarse sediments changed to the Huanghe beginning with Unit 3. Fine-grained sediment was still supplied from all rivers during the deposition of Unit 3. Early Holocene (Unit 2) sediments were characterized by oscillating grain size, clay minerals, and moderate εNd values. In this period, the dominant fine-sediment provenance changed from the Huanghe to the Changjiang, whereas coarse sediments most likely originated from western Korean rivers. The Unit 1 CYSM sediments were sourced primarily from the Changjiang, along with minor contributions from the western Korean rivers. Possible transport mechanisms concerning such changes in the sediment provenance include paleo-river pathways, tidal stress evolution, and the development of the Yellow Sea Warm Current and coastal circulation systems, depending on the sea level fluctuations.

Sign in / Sign up

Export Citation Format

Share Document