Abrupt weakening of the summer monsoon in northwest India ∼4100 yr ago
Abrupt weakening of the summer monsoon in northwest India ∼4100 yr ago
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4100 年前印度西北部夏季季风突然减弱
DOI：
10.1130/g35236.1
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发表时间：
2014-04-01
期刊：
影响因子：
5.8
通讯作者：
Petrie, Cameron A.
中科院分区：
文献类型：
--
作者：
Dixit, Yama;Hodell, David A.;Petrie, Cameron A.
气候变化被认为是印度河文明城市中心衰落的可能原因，类似于4000年前，但现有的古气候证据来自于远离印度河聚落分布的地点。本文报道了腹足类文石的氧同位素记录。来自印度哈里亚纳邦古奥拉克Kotla Dahar的全新世沉积物，它毗邻印度河定居点，记录了过去6.5K.Y.印度夏季风(ISM)的变化。O-18(A)在约4.1ka时增加了4%，这标志着与ISM减弱有关的湖泊流域蒸发/降水比的峰值。尽管气候和考古记录都存在年代不确定性，但印度西北部平原上的干旱事件4.1ka处于印度河去城市化开始的放射性碳年龄范围内，这表明气候可能在印度河文化转型中发挥了作用。
Climate change has been suggested as a possible cause for the decline of urban centers of the Indus Civilization similar to 4000 yr ago, but extant paleoclimatic evidence has been derived from locations well outside the distribution of Indus settlements. Here we report an oxygen isotope record of gastropod aragonite (PO.) from Holocene sediments of paleolake Kotla Dahar (Haryana, India), which is adjacent to Indus settlements and documents Indian summer monsoon (ISM) variability for the past 6.5 k.y. A4% increase in delta O-18(a) occurred at ca. 4.1 ka marking a peak in the evaporation/precipitation ratio in the lake catchment related to weakening of the ISM. Although dating uncertainty exists in both climate and archaeological records, the drought event 4.1 ka on the northwestern Indian plains is within the radiocarbon age range for the beginning of Indus de-urbanization, suggesting that climate may have played a role in the Indus cultural transformation.