Gondwana Pebble-Slate in the Rangit Valley Tectonic Window, Darjeeling Himalayas and its Significance

To the south of the Central crystalline zone of the Darjeeling Himalayas, in the interior parts of the frontal zone of the nappes, a sequence of the Lower Gondwana rocks occurs in a window, overlain by the tectonic cover of the Daling-Darjeeling group of metamorphites. A prominent marine fauna bearing pebble-slate horizon is developed at the base of this sequence. The stratigraphy and lithologic characters of this horizon are described in detail, and are considered significant in the context of the palaeogeography and tectonic evolution of this part of Himalaya.