Himalayan structure and tectonics

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Himalayan structure and tectonics
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India-Asia collision responsible for almost all
major structural features of central and eastern
Asia
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Wang et al., 2001
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Molnar and Tapponier, 1975
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Lithotectonic units after Hodges (2000)

• Transhimalayan zone
• Indus-Tsangpo suture zone
• Tibetan zone
• North Himalayan gneiss domes
• Greater Himalayan zone a.k.a. Greater Himalayan
  sequence
• Lesser Himalayan zone
• Subhimalayan zone
• Foreland basin

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Indus-Tsangpo suture zone Asian forarc deposits,
ophiolites, and Indian distal passive margin
sediments
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Transhimalayan zone Continental magmatic arc
related to Andean-style margin along south Asia
before collision
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North Himalayan gneiss domes Large tracts of
high-grade metamorphic and/or plutonic rocks
mantled by Tibetan zone sedimentary rocks
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Greater Himalayan zone a.k.a. Greater Himalayan
sequence Thick fault-bounded package of high-T
metasedimentary rocks and Al-rich leucogranites
exposed along Himalayan front
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Lesser Himalayan zone Fault-bounded low- to
medium-T metasedimentary rocks exposed in the
Himalayan foothills
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Major structural elements after Hodges (2000)

• South-vergent, low-angle, reverse-sense fault
  zonesMain Frontal Thrust, Main Boundary Thrust,
  and Main Central Thrust
• South Tibetan Detachment System
• Low-angle fault zones associated with
  north-Himalayan gneiss domes
• Strike-slip fault zones
• NorthSouth-striking normal fault systems

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South-vergent, low-angle, reverse-sense fault
zonesMain Frontal Thrust, Main Boundary Thrust,
and Main Central Thrust
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South Tibetan Detachment System (STD) Seperates
Greater Himalayan zone from Tibetan zone rocks
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diagram from M.P. Searle
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diagram from M.P. Searle
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Folded Orogenic Wedge
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Channel Flow
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Strike-slip fault zones Consistent dextral offset
accommodates eastward escape of Tibet
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Northsouth-striking normal fault
systems Accommodate eastwest extension and
eastward escape of Tibet
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