Panjal Traps
The Panjal Traps or the Tethyan Plume is a large igneous province (LIP) that erupted during the Early–Middle Permian in what is now north-western India. The Panjal Traps are associated with the opening of the Neo-Tethys Ocean, which resulted in the dispersal of the Cimmerian continental blocks from the north-eastern margin of Gondwana and possibly the break-up of this old and large continent.[1] In the Zanskar-Spliti-Lahaul area (in the north-western Himalayas and south-east Ladakh) the 30–150 m (98–492 ft)-thick basalts of the Panjal Traps are mostly exposed as massive (terrestrial) lava flows, but also as (marine) pillow lavas and hyaloclastites.[2]
The Panjal Traps were first documented in 1824 and were eventually named by British geologist Richard Lydekker in 1883,[3] but their origin, age, and relationship with surrounding and underlying rocks remained elusive for more than a century.[4] They remained one of the most understudied LIPs before being properly dated to 289 Ma in 2011.[5]
Geological setting
Late Carboniferous to
The slightly younger (Artinskian-Kazanian) Panjal Traps produced the largest magmatic province in north-western India. Its lava flows now covers 105 km2, from the eastern Zanskar-Spliti-Lahaul area to north-eastern Pakistan and they filled a rifted valley called the Zanskar-Spiti synclinorium.[2] The original extent of the Panjal Traps may have exceeded 0.2x106 km2, a distribution similar to those of the Emeishan LIP in south-western China and the Columbia River basalts in north-western United States.[6] In Ladakh and in the Kashmir Basin the flows are 2,500 m (8,200 ft) thick with a smaller amount of pyroclastics overlain by aphyric basaltic flows. In north-eastern Pakistan the Panjal flows are exposed as dykes cross-cutting the basement and Early Paleozoic layers, and as inter-layered magmatic flows on Late Plaeozoic to Early Mesozoic layers with Tethyan affinity.[2]
The eruption of the Panjal Traps was followed (Kazanian-Djulfian) by the emplacement of a succession of sediments, the result of the progressive thermo-tectonic subsidence of the Indian passive margin associated with the expanding Neo-Tethys.[2]
Tectonic implications
The Panjal Traps have been associated with either the
Late Carboniferous-Permian LIPs (such as
Paleomagnetic data from the Kashmir Valley indicate the Panjal eruption occurred at a paleolatitude of c. 33° (±5°)S.[9]
References
Notes
- ^ Chauvet et al. 2008, Introduction, p. 384
- ^ a b c d e Chauvet et al. 2008, Geological setting, pp. 384–386
- ^ Lydekker 1883
- ^ a b Shellnutt et al. 2014, Introduction, pp. 159–161
- ^ a b Shellnutt et al. 2011, Abstract
- ^ Stojanovic et al. 2016, Introduction, p. 116
- ^ Torsvik & Cocks 2013, pp. 1023–1024, Fig. 21, p. 1026
- ^ Shellnutt et al. 2015, Abstract
- ^ Stojanovic et al. 2016, Abstract
Sources
- Chauvet, F.; Lapierre, H.; Bosch, D.; Guillot, S.; Mascle, G.; Vannay, J.-C.; Cotten, J.; Brunet, P.; Keller, F. (2008). "Geochemistry of the Panjal Traps basalts (NW Himalaya): records of the Pangea Permian break-up". Bulletin de la Société Géologique de France. 179 (4): 383–395. . Retrieved 23 July 2016.
- OCLC 898867409.
- Shellnutt, J. G.; Bhat, G. M.; Brookfield, M. E.; . Retrieved 23 July 2016.
- Shellnutt, J. G.; Bhat, G. M.; Wang, K. L.; Brookfield, M. E.; Jahn, B. M.; Dostal, J. (2014). "Petrogenesis of the flood basalts from the Early Permian Panjal Traps, Kashmir, India: Geochemical evidence for shallow melting of the mantle". Lithos. 204: 159–171. . Retrieved 23 July 2016.
- Shellnutt, J. G.; Bhat, G. M.; Wang, K. L.; Yeh, M. W.; Brookfield, M. E.; Jahn, B. M. (2015). "Multiple mantle sources of the Early Permian Panjal Traps, Kashmir, India". American Journal of Science. 315 (7): 589–619. S2CID 131091884. Retrieved 23 July 2016.
- Stojanovic, D.; Aitchison, J. C.; Ali, J. R.; Ahmad, T.; Dar, R. A. (2016). "Paleomagnetic investigation of the Early Permian Panjal Traps of NW India; regional tectonic implications". Journal of Asian Earth Sciences. 115: 114–123. .
- Torsvik, T. H.; Cocks, L. R. M. (2013). "Gondwana from top to base in space and time". Gondwana Research. 24 (3): 999–1030. . Retrieved 23 July 2016.