Figure 4

Correlation of climatic variability recorded in the lithostratigraphy, δD (orange), δ¹⁸O (blue), of paleolake Karsandi water and ostracod abundance with Indus cultural changes. The calibrated radiocarbon ages (ka BP) are shown in black with red arrows pointing to their respective depths. OSL dates and depth of sand collection for dating are shown in blue. Grey bands denote the nearly pure gypsum deposits indicating periods of relatively lower rainfall and blue band denotes wetter periods. Roman numerals denote lithologic units. The Early phase of the Indus Civilization developed during increased monsoon intensity as indicated by lower GHW isotopes and high shell abundance after ~5.1 ± 0.2 ka BP. The Mature Harappan phase and peak in urbanism coincides with the lowest GHW isotopes and highest shell abundance between ~5.0 and ~4.4 ka BP. Note that the subsequent decline in urbanism and disappearance of Post-urban Harappan sites in this region is coincident with drying conditions suggested by reappearance of massive gypsum with increasing GHW isotopes and complete absence of ostracod and gastropod shells.