Reconstructing Late Quaternary Palaeo‐environmental change from the dryland fluvial landscape of the Southern Kachchh Mainland, western India: Insights from new OSL and sedimentological datasets

2020 ◽  
Vol 55 (10) ◽  
pp. 7041-7056 ◽  
Author(s):  
Archana Das ◽  
Jaquilin Joseph ◽  
Tarun Solanki ◽  
Nisarg Makwana ◽  
Gaurav Chauhan ◽  
...  
Keyword(s):  
Environmental Change ◽  
Late Quaternary ◽  
Western India ◽  
Fluvial Landscape

PRELIMINARY CHEMOSTRATIGRAPHY OF CAVE DEPOSITS IN THE PANTANAL WETLANDS (BRAZIL): INSIGHTS INTO LATE QUATERNARY ENVIRONMENTAL CHANGE

2018 ◽  
Author(s):  
Michael M. McGlue ◽  
◽  
Valdir Felipe Novello ◽  
Francisco W. Cruz ◽  
Rudney de Almeida Santos ◽  
...  
Keyword(s):  
Environmental Change ◽  
Late Quaternary ◽  
Cave Deposits

Optical dating of late Quaternary carbonate sequences of Saurashtra, western India

2017 ◽  
Vol 87 (1) ◽  
pp. 133-150 ◽  
Author(s):  
Komal Sharma ◽  
Nilesh Bhatt ◽  
Anil Dutt Shukla ◽  
Dae-Kyo Cheong ◽  
Ashok Kumar Singhvi
Keyword(s):  
Late Quaternary ◽  
Optically Stimulated Luminescence ◽  
Western India ◽  
Carbonate Sediments ◽  
Sampling Strategies ◽  
Aeolian Processes ◽  
Saurashtra Coast ◽  
Recent Deposition ◽  
Quartz Grains ◽  
Carbonate Deposits

AbstractBioclastic carbonate deposits that formed because of a combination of nearshore marine, fluvial, and aeolian processes, occur along the Saurashtra coast and in the adjacent interior regions of western India. Whether these carbonates formed by marine or aeolian processes has been debated for many decades. The presence of these deposits inland poses questions as to whether they are climate controlled or attributable to postdepositional tectonic uplift. In particular, the debate centres on chronologic issues including (1) appropriate sampling strategies and (2) the use of 230Th/234U and 14C ages on the bulk carbonates. Using traces (<1%) of quartz grains trapped in carbonate matrices, optically stimulated luminescence (OSL) dating of quartz grains, deposited along with the carbonate grains, provides ages for the most recent deposition events. The OSL ages range from >165 to 44 ka for the shell limestones, 75–17 ka for the fluvially reworked sheet deposits, and 80–11 ka for miliolites deposited by aeolian processes. These are younger than the 230Th/234U and 14C ages and suggest that the inland carbonate deposits were reworked from older carbonate sediments that were transported during more arid phases.

Elemental proxy evidence for late Quaternary palaeoenvironmental change in southern African sedimentary records: interpretation and applications

2021 ◽  
Author(s):  
M.S. Humphries
Keyword(s):  
Environmental Change ◽  
Southern Africa ◽  
Southern Oscillation ◽  
Late Quaternary ◽  
Rainfall Variability ◽  
Analytical Techniques ◽  
Summer Rainfall ◽  
Geochemical Data ◽  
Complex Nature ◽  
Cape Coast

Abstract Sediments are the most important source of Late Quaternary palaeoclimate information in southern Africa, but have been little studied from a geochemical perspective. However, recent advances in analytical techniques that allow rapid and near-continuous elemental records to be obtained from sedimentary sequences has resulted in the increasing use of elemental indicators for reconstructing climate. This paper explores the diverse information that can be acquired from the inorganic component of sediments and reviews some of the progress that has been made over the last two decades in interpreting the climatic history of southern Africa using elemental records. Despite the general scarcity of elemental records, excellent examples from the region exist, which provide some of the longest and most highly resolved sequences of environmental change currently available. Records from Tswaing crater and marine deposits on the southern KwaZulu-Natal coastline have provided rare glimpses into hydroclimate variability over the last 200 000 years, suggesting that summer rainfall in the region responded predominantly to insolation forcing on glacial-interglacial timescales. Over shorter timescales, lakes and wetlands found in the Wilderness embayment on the southern Cape coast and along the Maputaland coast in north-eastern South Africa have yielded highly-resolved elemental records of Holocene environmental change, providing insight into the changing interactions between tropical (e.g., El Niño-Southern Oscillation) and temperate (e.g., mid-latitude westerlies) climate systems affecting rainfall variability in the region. The examples discussed demonstrate the multiple environmental processes that can be inferred from elemental proxies and the unique insight this can provide in advancing our understanding of past climate change on different timescales. The interpretation of geochemical data can be complicated by the complex nature of sedimentary environments, various proxy assumptions and analytical challenges, and the reliability of sediment-based climate reconstructions is substantially enhanced through multi-proxy approaches.

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