印度南部湖泊的碳酸盐及沉积学记录数据集(3700年以来)

过去3700年间，在Thimmannanayakanakere（TK）地区，高（低）χlf值代表高（低）降雨量。粒度变化表明，干旱（湿润）时期TK湖水位较低（高），砂%含量相应较高（低）。因此，砂含量与χlf及其它岩石磁性参数存在负相关关系。HIRM（硬磁性矿物指标，如赤铁矿和针铁矿）指示气候的干旱程度，TK沉积物中的高（低）HIRM值表示干旱（潮湿）条件。因此，砂含量与HIRM呈正相关。相比之下，在低降雨量期间，细粉砂和粘土含量较低，反之亦然。所以，细粉砂及粘土与χlf及其它岩石磁性参数呈正相关，与HIRM呈负相关。TK沉积物中磁性矿物主要存在于细粉砂组分，证明了细粉砂含量与磁化率之间的正相关关系。碳酸盐含量也指示了古降雨条件，干旱（潮湿）气候条件下其值较高（低）。我们基于χlf、砂含量和碳酸盐含量，推断过去3700年间TK湖泊水位的变化情况。

Over the past 3700 years in the Thimmannanayakanakere (TK) region, high (low) χlf (low-field magnetic susceptibility) values correspond to high (low) rainfall amounts. Grain size variations indicate that during arid (humid) periods, the water level of Lake TK was lower (higher), with correspondingly higher (lower) sand percentage contents. Thus, sand content exhibits a negative correlation with χlf and other rock magnetic parameters. HIRM (Hard Isothermal Remanent Magnetization, a proxy for hard magnetic minerals such as hematite and goethite) indicates climatic aridity; high (low) HIRM values in TK sediments represent arid (humid) conditions. Therefore, sand content shows a positive correlation with HIRM. In contrast, during periods of low rainfall, fine silt and clay contents are lower, and vice versa. Accordingly, fine silt and clay contents have positive correlations with χlf and other rock magnetic parameters, and negative correlations with HIRM. Magnetic minerals in TK sediments are mainly concentrated in the fine silt fractions, which confirms the positive correlation between fine silt content and magnetic susceptibility (χlf). Carbonate content also acts as a proxy for paleorainfall conditions, with higher (lower) values under arid (humid) climatic conditions. We reconstructed the changes in Lake TK’s water levels over the past 3700 years based on χlf, sand content, and carbonate content.