No abstract

No abstract

Integrating multiproxy results (geochemistry, mineral magnetism, grain size, and C/N ratio variability supported by 14C AMS dating), obtained from a 1.4-m sediment core retrieved from high-altitude Anchar Lake, Kashmir Valley, NW Himalaya, we present a 6000-years record of paleoenvironmental and paleolimnological shifts. Phase 1 (6000–4700 cal. yr BP) revealed a wetter climate with a significant terrestrial input corresponding to the gradual strengthening of the westerlies. Phase 2 (4700–3900 cal. yr BP) reflects an overall improved westerly precipitation and autochthonous sources of organic matter (OM). Magnetic parameters also indicate higher lake levels and reducing conditions during this phase. Phase 2 was followed by a gradual diminishing pattern of the westerlies as also represented by phase 3 (3900–2500 cal. yr BP) and phase 4 (2500–1600 cal. yr BP) indicating moderate precipitation conditions, catchment stability, and temperate and/or cold-dry climatic conditions. Phase 5 (1600–500 cal. yr BP) revealed the prevalence of moderately cold/dry and further subdued westerly precipitation. Phase 6 (500 cal. yr BP to present) is represented by reduced westerly precipitation, shrinking lake margins, and significant terrestrial/anthropogenic controls over the lake basin. Mineral magnetic parameters indicate reducing lake bottom water conditions and eutrophication during this phase due to anthropogenic activities. These paleoenvironmental shifts reveal near synchronous changes (within dating uncertainties) with other regional paleoclimate records close to the present Anchar Lake location and reflect the gradual late-Holocene diminishment of the amount of winter/early summer moisture provided by the mid-latitude westerlies.

We present a comprehensive record of Holocene (11,590–628 cal. yr BP) climate and hydrographic changes around the Wular Lake located in Kashmir Valley, India. Based on the multi-proxy investigations, we have identified three phases of wet climate conditions that prevailed from the commencement of the Holocene Epoch – 9000 cal. yr BP, 8100–6650 cal. yr BP and 6350–5000 cal. yr BP, whereas periods of dry climate were observed during 9000–8100 cal. yr BP, 6650–6350 cal. yr BP and ~5000 to 4000 cal. yr BP. The results also suggested that the lake widened and deepened significantly around 6350–5000 cal. yr BP. The results indicated desiccation and the exposure of the lake margin around 5000–4500 cal. yr BP. The sedimentation rate since 4500–628 cal. yr BP was quite low for detailed paleoclimate interpretations. Oscillations in lake extension and deepening appear to be due to changing intensity of westerly moisture in the region, and we correlate several of the low lake-level phases to the Bond events caused by North Atlantic ice rafting events.

No abstract