Three Holocene and late Pleistocene glacial stages inferred from moraines in the Lingshi and Thanza village areas, Bhutan

Abstract

Moraines formed by valley glaciers in Lingshi area, northwestern Bhutan constitute three distinct stages with contrasts in the spatial distribution and size of moraines, and surface features such as clasts, soils and vegetation. Moraines in the Thanza Village area, northern Bhutan, show three stages with similar characteristics to those in the Lingshi area. Using morphostratigraphic criteria, these three stages correlate with some glacial stages in the Khumbu Himal, eastern Nepal. Dates from moraines in the Khumbu Himal provide a tentative chronological sequence of these three stages. Valley glaciers in Bhutan expanded during the following periods: (1) the Takaphu and Raphsthreng Stages are the Little Ice Age and late Holocene glacial advances; (2) the Jykhuje and Tenchey Stages represent the Late Glacial and/or early Holocene glacial advances; and (3) the Lingshi Dzong and Lunana Stages are coincident with the Last Glacial period.