Geological map of the Karakoram fault zone, Eastern Karakoram, Ladakh, NW Himalaya

Abstract

Abstract:The Eastern Karakoram is a remote and under studied region of Ladakh in the northwestern Himalaya. The geology of the area provides insight into the evolution of the south Asian margin since the Paleozoic and is dominated structurally by the Karakoram fault, an ∼800 km long dextral strike-slip fault that bounds western Tibet. In this paper, a 1:250,000 geological map is presented based upon fieldwork and interpretation of satellite imagery. An overview of the geology of the Eastern Karakoram is also presented and includes a discussion of the architecture and kinematics of the central segment of the Karakoram fault. The construction of the map has aided our understanding of the initiation and evolution of the Karakoram fault and of the geology of the south Asian margin in this region.

Testing the Stress-Gradient Hypothesis at the Roof of the World: Effects of the Cushion Plant Thylacospermum caespitosum on Species Assemblages

“…Only the higher content of OM in soils below cushions (in Nubra only) was consistent with earlier reports [9]. The markedly high contents of Mg and K in soils from Nubra are caused by the specific geochemistry of the Karakorum batholith (rich in Mg) and leucogranites (rich in K) [35]. The main source of enhanced nutrient levels in the soil below cushions is the decomposing dead tissue accumulated within them [10].…”

“…The relief is characterised by sharp and rugged ridges. Valleys are narrow and steep and regularly end in glaciers, the fronts of which usually start at c. 5300 m. The bedrock consists mostly of Nubra-Siachen batholith and leucogranites [35]. In a wetter and stronly glaciated Karakoram, the cushions descend to lower elevations compare to dry Little Tibet where the cushions ascend to 5900 m due to a poor glaciation and relatively well developed soils at high elevations [33].…”

“…It is of relatively flat relief with gentle slopes bearing many rounded and poorly glaciated peaks, reaching 6666 m (Lungser Kangri). The substrate ranges from siliceous rocks (Precambrian granites, Tso Moriri gneiss) to calcareous and saline sediments [35]. At lower elevations much of the area is covered by cold desert and semi-desert vegetation, a steppe zone is found at middle elevations up to c. 5000–5400 m, alpine grasslands form a narrow belt above the steppe zone and subnival vegetation is developed at the highest elevations of 5700–6000 m [33], [34].…”

Fault weakening across the frictional‐viscous transition zone, Karakoram Fault Zone, NW Himalaya

“…The central portion of the KFZ in Ladakh, NW India, consists of subparallel strands linked by a transpressional left‐hand jog (Figure ). The macroscopic geometry of the fault zone in this region has been extensively mapped by Phillips []. In this region, the KFZ juxtaposes midcrustal igneous and metasedimentary units of the southern Asian continental margin to the NE with intrusive and extrusive magmatic units of the Ladakh arc terrane to the SW [ Kirstein et al ., ; Phillips , ].…”

“…The macroscopic geometry of the fault zone in this region has been extensively mapped by Phillips []. In this region, the KFZ juxtaposes midcrustal igneous and metasedimentary units of the southern Asian continental margin to the NE with intrusive and extrusive magmatic units of the Ladakh arc terrane to the SW [ Kirstein et al ., ; Phillips , ]. The Asian metasedimentary units include the Nubra Formation, Saser Formation, Pangong Metamorphic Complex (PMC), and Pangong Transpressional Zone (PTZ), collectively termed the Eastern Karakoram metamorphic complex (EKMC).…”