Panjal Traps
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The Panjal Traps or the Tethyan Plume is a
large igneous province A large igneous province (LIP) is an extremely large accumulation of igneous rocks, including intrusive ( sills, dikes) and extrusive (lava flows, tephra deposits), arising when magma travels through the crust towards the surface. The format ...
(LIP) that erupted during the Early–
Middle Permian The Guadalupian is the second and middle series/epoch of the Permian. The Guadalupian was preceded by the Cisuralian and followed by the Lopingian. It is named after the Guadalupe Mountains of New Mexico and Texas, and dates between 272.95 ± 0. ...
in what is now north-western
India India, officially the Republic of India, is a country in South Asia. It is the List of countries and dependencies by area, seventh-largest country by area; the List of countries by population (United Nations), most populous country since ...
. The Panjal Traps are associated with the opening of the Neo-Tethys Ocean, which resulted in the dispersal of the
Cimmerian The Cimmerians were an Ancient Iranian peoples, ancient Eastern Iranian languages, Eastern Iranian peoples, Iranic Eurasian nomads, equestrian nomadic people originating in the Pontic–Caspian steppe, part of whom subsequently migrated into W ...
continental blocks from the north-eastern margin of
Gondwana Gondwana ( ; ) was a large landmass, sometimes referred to as a supercontinent. The remnants of Gondwana make up around two-thirds of today's continental area, including South America, Africa, Antarctica, Australia (continent), Australia, Zea ...
and possibly the break-up of this old and large continent. In the
Zanskar Zanskar, Zahar (locally) or Zangskar, is the southwestern region of Kargil district in the Indian union territory of Ladakh. The administrative centre of Zanskar is Padum. Zanskar, together with the rest of Ladakh, was briefly a part of the kin ...
- Spliti-Lahaul area (in the north-western Himalayas and south-east Ladakh) the -thick basalts of the Panjal Traps are mostly exposed as massive (terrestrial) lava flows, but also as (marine)
pillow lava Pillow lavas are lavas that contain characteristic pillow-shaped structures that are attributed to the extrusion of the lava underwater, or ''subaqueous extrusion''. Pillow lavas in volcanic rock are characterized by thick sequences of discontinu ...
s and
hyaloclastite Hyaloclastite is a volcanoclastic accumulation or breccia consisting of glass (from the Greek ''hyalus'') fragments (clasts) formed by quench fragmentation of lava flow surfaces during submarine or subglacial extrusion. It occurs as thin marg ...
s. The Panjal Traps were first documented in 1824 and were eventually named by British geologist
Richard Lydekker Richard Lydekker (; 25 July 1849 – 16 April 1915) was a British naturalist, geologist and writer of numerous books on natural history. He was known for his contributions to zoology, paleontology, and biogeography. He worked extensively in cata ...
in 1883, but their origin, age, and relationship with surrounding and underlying rocks remained elusive for more than a century. They remained one of the most understudied LIPs before being properly dated to 289 Ma in 2011.


Geological setting

Late Carboniferous to
Early Permian 01 or 01 may refer to: * The year 2001, or any year ending with 01 * The month of January * 1 (number) Music * '01 (Richard Müller album), ''01'' (Richard Müller album), 2001 * 01 (Urban Zakapa album), ''01'' (Urban Zakapa album), 2011 * ''01011 ...
deposits of Tethyan affinity in the Zanskar-Spiti area are mostly terrigenous, detrital sedimentary rocks, although some magmatic activity documented in Pakistan and central Nepal has been associated with this period. These sedimentary layers are associated with the erosion that followed the uplift of the margins of the newly rifted Indian continent. In the eastern and central Himalayas more voluminous volcanic eruptions have been documented from the same period. The Abor volcanics produced of
basalt Basalt (; ) is an aphanite, aphanitic (fine-grained) extrusive igneous rock formed from the rapid cooling of low-viscosity lava rich in magnesium and iron (mafic lava) exposed at or very near the planetary surface, surface of a terrestrial ...
ic to
andesitic Andesite () is a volcanic rock of intermediate composition. In a general sense, it is the intermediate type between silica-poor basalt and silica-rich rhyolite. It is fine-grained (aphanitic) to porphyritic in texture, and is composed predomina ...
flows and
tuff Tuff is a type of rock made of volcanic ash ejected from a vent during a volcanic eruption. Following ejection and deposition, the ash is lithified into a solid rock. Rock that contains greater than 75% ash is considered tuff, while rock co ...
s. In the
Late Permian Late or LATE may refer to: Everyday usage * Tardy, or late, not being on time * Late (or the late) may refer to a person who is dead Music * ''Late'' (The 77s album), 2000 * Late (Alvin Batiste album), 1993 * Late!, a pseudonym used by Dave Groh ...
(
Sakmarian In the geologic timescale, the Sakmarian is an age or stage of the Permian period. It is a subdivision of the Cisuralian Epoch or Series. The Sakmarian lasted between 293.52 and million years ago (Ma). It was preceded by the Asselian and fo ...
-
Roadian In the geologic timescale, the Roadian is an age or stage of the Permian. It is the earliest or lower of three subdivisions of the Guadalupian Epoch or Series. The Roadian lasted between and million years ago (Ma). It was preceded by the Kun ...
) the theoliitic Nar-Tsum(?) produced of spilites and Bhote Kosi basalts in southern Tibet. The slightly younger (
Artinskian In the geologic timescale, the Artinskian is an age (geology), age or stage (stratigraphy), stage of the Permian. It is a subdivision of the Cisuralian Epoch (geology), Epoch or series (stratigraphy), Series. The Artinskian likely lasted between ...
- 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. The original extent of the Panjal Traps may have exceeded 0.2 million km2, a distribution similar to those of the Emeishan LIP in south-western China and the
Columbia River basalts The Columbia River Basalt Group (CRBG) is the youngest, smallest and one of the best-preserved continental flood basalt provinces on Earth, covering over mainly eastern Oregon and Washington, western Idaho, and part of northern Nevada. The b ...
in north-western United States. In Ladakh and in the Kashmir Basin the flows are 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 A basement is any Storey, floor of a building that is not above the grade plane. Especially in residential buildings, it often is used as a utility space for a building, where such items as the Furnace (house heating), furnace, water heating, ...
and Early Paleozoic layers, and as inter-layered magmatic flows on Late Plaeozoic to Early Mesozoic layers with Tethyan affinity. 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 Tectonic subsidence is the Subsidence, sinking of the Earth's Crust (geology), crust on a large scale, relative to crustal-scale features or the geoid. The movement of Plate tectonics, crustal plates and accommodation spaces produced by Fault (geol ...
of the Indian passive margin associated with the expanding Neo-Tethys.


Tectonic implications

The Panjal Traps have been associated with either the Mid-Capitanian (260 Ma) or End-Permian (251 Ma) mass extinction events. Analyses of zircon crystals have, however, yielded an 206U/238Pb age of 289±2 Ma — considerably older than these mass extinctions. The Panjal Traps can, nevertheless, be linked to the African large low-shear-velocity province (or superplume) and, as such, is most likely responsible for the widespread flood basalts in the Himalayas, but the
Siberian Traps The Siberian Traps () are a large region of volcanic rock, known as a large igneous province, in Siberia, Russia. The massive eruptive event that formed the trap rock, traps is one of the largest known Volcano, volcanic events in the last years ...
(251 Ma) are probably a better candidate for these younger mass extinctions. Late Carboniferous-Permian LIPs (such as
Jutland Jutland (; , ''Jyske Halvø'' or ''Cimbriske Halvø''; , ''Kimbrische Halbinsel'' or ''Jütische Halbinsel'') is a peninsula of Northern Europe that forms the continental portion of Denmark and part of northern Germany (Schleswig-Holstein). It ...
, Panjal, Tarim, Emeishan and Siberia) were emplaced before the break-up of Pangaea whereas the post-Permian LIPs were involved in the break-up of the supercontinent. Mantle plume-derived LIPs share features such as large-volume flood basalts, short duration, uplift and doming of the crust before eruption, and high temperature-melts such as
komatiite Komatiite is a type of ultramafic mantle-derived volcanic rock defined as having crystallised from a lava of at least 18 wt% magnesium oxide (MgO). It is classified as a 'picritic rock'. Komatiites have low silicon, potassium and aluminium, and ...
s and
picrite Picrite basalt or picrobasalt is a variety of high-magnesium olivine basalt that is very rich in the mineral olivine. It is dark with yellow-green olivine phenocrysts (20-50%) and black to dark brown pyroxene, mostly augite. The olivine-rich ...
s. The chemical and isotopic composition of samples of basalt taken from the eastern Kashmir Valley are similar to within-plate basalts, and probably derived from a
spinel Spinel () is the magnesium/aluminium member of the larger spinel group of minerals. It has the formula in the cubic crystal system. Its name comes from the Latin word , a diminutive form of ''spine,'' in reference to its pointed crystals. Prop ...
peridotite Peridotite ( ) is a dense, coarse-grained igneous rock consisting mostly of the silicate minerals olivine and pyroxene. Peridotite is ultramafic, as the rock contains less than 45% silica. It is high in magnesium (Mg2+), reflecting the high pr ...
source. Samples taken from the western side of the valley are more primitive, derived from a more depleted source. This suggests that Panjal made a transition from a newly formed continental setting, where the basalt composition was 'enriched OIB-like', to an old ocean basin, where the composition was 'depleted
MORB A mid-ocean ridge (MOR) is a seafloor mountain system formed by plate tectonics. It typically has a depth of about and rises about above the deepest portion of an ocean basin. This feature is where seafloor spreading takes place along a div ...
-like'. Chemically, the Panjal basalts are similar to those from post-Permian/post-Pangaean LIPs. Paleomagnetic data from the Kashmir Valley indicate the Panjal eruption occurred at a paleolatitude of c. 33° (±5°)S.


References


Notes


Sources

* * * * * * * {{Large igneous provinces Geology of the Himalaya Geology of India Large igneous provinces Permian volcanism