Palaeoenvironmental implications of evaporative gaylussite crystals from Lonar Lake, central India
Palaeoenvironmental implications of evaporative gaylussite crystals from Lonar Lake, central India
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DOI：
10.1002/jqs.2625
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发表时间：
2013-05-01
影响因子：
2.3
通讯作者：
Brauer, A.
中科院分区：
文献类型：
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作者：
Anoop, A.;Prasad, S.;Brauer, A.
我们已经进行了岩相学，矿物学，地球化学和同位素调查的碳酸盐矿物内发现的10米长的核心从Lonar湖，印度中部，其目的是评估其潜在的古环境代理。该岩心涵盖了整个全新世，是印度中部第一个日期明确的高分辨率记录。虽然方解石和/或文石被发现在整个核心，矿物钙铝榴石被发现只有在两个特定的间隔（46303890和2040560卡BP）。水化学和同位素数据从流入的河流和湖泊沃茨表明，碳酸盐沉淀在这个湖泊中的碳酸盐岩过程中发挥了主导作用。同位素（18 O和13 C）的蒸发钙铝榴石晶体和残留的块状碳酸盐（方解石）从长的核心研究表明，蒸发是18 O富集的矿物的主要控制。然而，在13 C的情况下，其他机制，例如甲烷生成（钙铝榴石）和浮游植物生产力（碳酸钙），在某些时间段发挥额外的重要作用。我们还讨论了我们的调查古气候重建和晚全新世季风变化的相关性。版权所有（c）2013约翰威利父子有限公司
We have undertaken petrographic, mineralogical, geochemical and isotopic investigations on carbonate minerals found within a 10-m-long core from Lonar Lake, central India, with the aim of evaluating their potential as palaeoenvironmental proxies. The core encompasses the entire Holocene and is the first well-dated high-resolution record from central India. While calcite and/or aragonite were found throughout the core, the mineral gaylussite was found only in two specific intervals (46303890 and 2040560 cal a BP). Hydrochemical and isotope data from inflowing streams and lake waters indicate that evaporitic processes play a dominant role in the precipitation of carbonates within this lake. Isotopic (18O and 13C) studies on the evaporative gaylussite crystals and residual bulk carbonates (calcite) from the long core show that evaporation is the major control on 18O enrichment in both the minerals. However, in case of 13C additional mechanisms, for example methanogenesis (gaylussite) and phytoplankton productivity (calcium carbonate), play an additional important role in some intervals. We also discuss the relevance of our investigation for palaeoclimate reconstruction and late Holocene monsoon variability. Copyright (c) 2013 John Wiley & Sons, Ltd.