Late Quaternary palaeoclimatic reconstruction from the lacustrine sediments of the Sambhar playa core, Thar Desert margin, India

2006 ◽  
Vol 233 (3-4) ◽  
pp. 252-270 ◽  
Author(s):  
R. Sinha ◽  
W. Smykatz-Kloss ◽  
D. Stüben ◽  
S.P. Harrison ◽  
Z. Berner ◽  
...  
Keyword(s):  
Late Quaternary ◽  
Lacustrine Sediments ◽  
Thar Desert ◽  
Palaeoclimatic Reconstruction

scholarly journals Influences of forested and grassland vegetation on late Quaternary ecosystem development as recorded in lacustrine sediments

2019 ◽  
Vol 92 (1) ◽  
pp. 201-215 ◽  
Author(s):  
Kendra K. McLauchlan ◽  
Ioan Lascu ◽  
Emily Mellicant ◽  
Robert J. Scharping ◽  
Joseph J. Williams
Keyword(s):  
Chemical Weathering ◽  
Forest Type ◽  
Late Quaternary ◽  
Sediment Cores ◽  
Lacustrine Sediments ◽  
Parent Material ◽  
Elemental Abundance ◽  
Sediment Delivery ◽  
Sedimentary Sequences ◽  
Northern United States

AbstractGeosphere-biosphere interactions are ubiquitous features of the Earth surface, yet the development of interactions between newly exposed lithologic surfaces and colonizing plants during primary succession after glaciation are lacking temporal detail. To assess the nature, rate, and magnitude of vegetation influence on parent material and sediment delivery, we analyzed ecosystem and geochemical proxies from lacustrine sediment cores at a grassland site and a forested site in the northern United States. Over time, terrigenous inputs declined at both sites, with increasing amounts of organic inputs toward present. The similarities between sites were striking given that the grassland sequence began in the Early Holocene, and the forested sequence began after the last glacial maximum. Multiple mechanisms of chemical weathering, hydrologic transport, and changes in source material potentially contribute to this pattern. Although there were strong links between vegetation composition and nitrogen cycling at each site, it appears that changes in forest type, or from oak woodland to grassland, did not exert a large influence on elemental (K, Ti, Si, Ca, Fe, Mn, and S) abundance in the sedimentary sequences. Rather, other factors in the catchment-lake system determined the temporal sequence of elemental abundance.

Vegetation History of Pleasant Island, Southeastern Alaska, since 13,000 yr B.P.

1996 ◽  
Vol 46 (2) ◽  
pp. 161-175 ◽  
Author(s):  
Barbara C. S. Hansen ◽  
Daniel R. Engstrom
Keyword(s):  
Vegetation History ◽  
Lodgepole Pine ◽  
Late Quaternary ◽  
Lacustrine Sediments ◽  
Tsuga Heterophylla ◽  
Temperature And Precipitation ◽  
Early Arrival ◽  
Peatland Development ◽  
History Of ◽  
Lake Catchment

A 13,000-year history of late-Quaternary vegetational and climatic change has been derived from lacustrine sediments from Pleasant Island in the Glacier Bay region of southeastern Alaska. Early arrival of lodgepole pine and mountain hemlock, indicated by the presence of pollen and conifer stomata, suggests expansion from refugia in the Alexander Archipelago. A short-term climatic reversal, possibly correlated with the European Younger Dryas, is inferred from the expansion of tundra elements and deposition of inorganic sediments between 10,600 and 9900 14C yr B.P. Two peat cores from the lake catchment verify Holocene vegetation changes and aid in the separation of biogenic from climatic forces affecting vegetation history. Differences in pollen representation among the three cores illustrate the variation among pollen-collecting substrates, as well as the spatial heterogeneity of peatland development and its dependence on local hydrology. Initial peat accumulation and soil paludification, occasioned by increases in temperature and precipitation in the early Holocene, allowed western and mountain hemlock to replace sitka spruce 8500–8000 yr B. P. Open muskeg became widespread about 7000 yr B. P. and allowed lodgepole pine to reinvade the region after a 2000-yr absence. The extensive replacement of fen elements by bog taxa at 3400 yr B. P. suggests increased paludification due to changing hydrologic conditions; its correlation with the upland expansion of Tsuga heterophylla suggests the onset of a cooler/wetter Neoglacial climate in southeastern Alaska.

scholarly journals Angular Unconformity of the Late Quaternary Strata in the Hetao Basin, North of the Ordos Block (West China): Timing and Its Tectonic Implications

2021 ◽  
Vol 9 ◽  
Author(s):  
Luanxi Bai ◽  
Xiwei Xu ◽  
Hao Luo ◽  
Kang Li ◽  
Xibin Tan ◽  
...  
Keyword(s):  
Late Quaternary ◽  
Lacustrine Sediments ◽  
Tibet Plateau ◽  
Tectonic Activity ◽  
West China ◽  
The North ◽  
Ordos Block ◽  
The Pacific ◽  
Long Time ◽  
Lacustrine Facies

Following the uplift of the Tibet Plateau and the continuous subduction of the Pacific Plate, graben faulting began to appear around the Ordos Block in the Cenozoic. The Hetao Basin is a Cenozoic rift basin between the Ordos Block and the Yinshan Mountains, and Late Quaternary sedimentary strata, which have lacustrine facies, are widely distributed inside this basin. However, the evolution of the Hetao Basin and its related fault systems has been debated for a long time due to the lack of tectonic evidence. In this study, four sections named Haolaigou, Bianqianghao, Huhesala, and Hazigai are selected along the north margin of the Hetao Basin. With the lithology and structural analysis of the Upper Pleistocene series in these sections, two new angular unconformities are found within the 10 m thick sedimentary sequence of the lacustrine sediments. Based on the dating results, we speculate that these two upper and lower angular unconformities are formed between 33 ka BP and 40 ka BP, and 60 ka BP and 80 ka BP, respectively. The angular unconformities also provide tectonic constraints for the latest and ongoing tectonic activity in the Quaternary. This tectonic movement begins at around 80 ka BP and causes two different unconformities of the lower strata with varying degrees of deformation (tilt) but also leads to the final death of the ancient lake.

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