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Triassic of spiti in phenerozoic stratygraphy is described by abhimanyu singh is good experieced
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Sedimentary strata of Triassic age are widely developed in India both in the peninsula and in the extra-peninsular part. While freshwater Triassic sediments were deposited in the peninsular India in a series of fluvial and lacustrine basins which later sank along trough faults, Marine sediments of this age are extremely rare in this area. However, the presence of marine rocks of the upper-most Trias has been recognised in the subsurface in Banni, Kachchh by the Oil and Natural Gas Commission. The horizon was located at a depth of about 1700 m below the surface.
Marine Triassic strata are well known in the extra-peninsular India right from Kashmir to Sikkim and beyond. Excellent section are known from Pir Panjal Range, Lidder valley, Sind valley, Wardwan, Khunumu-Khrew, Pastannah, Guryul ravine and other places in Kashmir. In Ladakh, these are exposed in Dras valley, Zoji-la, Zanskar basin, Rupshu, Lach-1ung-1a, Yunnam and parts of northeastern Ladakh. The classical section of Lilang valley in Spiti is well known for its rich fossil content and well-defined faunal assemblages. Niti and Painkhanda sections of northeastern Kumoan are equally well known. Triassic rocks are also exposed in Dharma and Lissar valleys of eastern Johar and parts of Byans and Kali and Kuti valleys of northeastern Kumoan. In Sikkim, the Triassic rocks are exposed on the eastern side of Lachi Hill and are dated as Middle Trias. Similar strata continue beyond the political boundary of India into Burma and Burmo-Siamese frontier. To the west also, they continue into the Punjab-Salt Range and beyond.
The Permo-Triassic boundary has long been a problem to geologists all over the world and a general agreement on this issue is still
Middle trias:-
it is coposed of Daonella limestone and shale.
The most typical fossil belong to the genus ceratites; besides it are the other cephelopods ptycbite, tracbyceras, xenaspis,monophyllites, gymnite, sturia, proarcestes, isculites, hollandites, dalmanites,nautilus,orthoceras.
The brachiopods are spiriferina and spirigera; daonella and halobia are the leading lamellibranchs
limestone is the zone of joannites thanamensis. Tha limestone overlaying this is the halobia limestone characterised by halobia cf. Comata which is a typically european fossil of the julic substage of the carnic.
which have a thickness of 150 m and consists of shales with intercalation of shaly limestone. They show fossil horizon a little above the base and again at 100 m above the base. The lower horizon contain trachyceras aff.ariae, joannites cf. Cymbiformic, monophyllites cf. Simonyi ,etc. The upper horizon yielded only one ill-preserved ammonoid (paratropite species) and a several brachipods and bivalves:
Brachiopods... Rhynchonell laucana, R.himaica, spiriferina shalshalensis, s.gregaria,
Bivalves... Lilangina nobilis, pomarangina haydeni, lima sp.
and brown quartzites, 90 m thick, which form a conspicuous horizon visible from a distance. Most of its fossils are also found in monotis shale, but spirigera maniensis is restricted to it.
the triassic sequence are thick massive liemstones and dolomites which griesbach originally included in his rhaetic system. There total thickness is of the order of 800 m and the bear a striking resemblance to the dachsteinkalk of the alpine region both in lithology and stratigraphical position. Fossils have been found between 60 and 100 m from the base, amongst which are—megalodon ladakhensis, entolium cf. Subdemissum, pecten chabrangensis, lima cumaunica, spirigera noetlingi, spiriferina cf. Haueri.
PAINKHANDA(KUMAON):
Excellent section of the tries are exposed in the bambanag and Shalshal cliffs in the north-western part of kumaon. The lowest three beds of the tries contain the otoceras-ophiceras fauna in which, besides species of these, there are Episageceras dalailamae, hungarite sp.,
The painkhanda section , though similar to than in spiti , has some variation. The ladinic stage dwindles down to an insignificant 28 cms and upper triass is also much less thick. In table is presented the stratigraphy division, the lithology, invertebrate fauna, characteristic spore-pollen taxa and standard stratigraphic equivalent. The kuling formation of upper Permian underlies the shal shal formation.
also in northern kumaon, near the border with Tibet. In the latter region, however, it has been divided into 1.chocolate series 2.kalapani limestone 3.kuti shale 4.kioto limestone. CHOCOLATE FORMATION …. Early Triassic Definition : Heim and Gansser (1939) described brown weathering limestone and shale of Lower Triassic age in Malla Johar area as Chocolate series. This has been redesignated as chocolate Formation by Kumar et. Al. (1977). Etymology : The formation is named after the colour of the weathered outcrop. Type section : The rocks are well exposed at the confluence of Shalshal and Yong rivers.
Definition: A thick sequence of rhythmic alternations of black friable shale and hard calcareous shale overlying Kalapani Limestone is named Kuti Shale by Henri and Gansser (1939).
Type section : The best exposure is seen in Yang valley . Lithology : The rock is predominantly a shale sequence. Thickness : It is about 418 m thick. Subdivisions : The Kuti Shale is divided into 3 members haying gradational contacts. They are as follows:
Kuti C 100 m Shale, more sandy than the underlying Kuti B Member 20-30cm thick bands silty shale, thick bands of limestone Kuti B 280 m Rhythmically interlayered 50 cm - 1 m thick greyishblack friable shale and a decimetre thick hard calcareous shale Kuti A 136 m Black friable shale alternating with black shaly limestone. Laminated black shale dominates over shaly imestone Contact relations : The contact is gradational at the lower contact with Kalapani Limestone. Fossils and age : Kumar et. al. (1977) assigned this unit to Noric.
Deffination : it is a dark blue, well bedded, limestone with oolite in the lower part Type section: kioto limestone is well developed in the belt extending from northwest NEPAL to GARHWAL. Lithology: the rock is predominantly a limestone sequence. Thickness: 500 m thick in the garhwal.
Triassic rocks, known as ceratite beds, are well developed in salt range on either side of Indus. A small unconformity intervenes between the Permian and trias; a conglomerate marking the break in deposition is found near siram ki dhok, and a marked change occur in fauna with the earliest Triassic rocks. Ceratite limestone which is the hard thin bedded light grey limestone containing numerous gyronites frequens. The otoceras horizon is probably represented by the unfossiliferous sands and clays which lie between this limestone and the chidru beds of upper productus limestone. The lower ceratite limestone is overlain by thik greyish green marly beds with limestone beds, called the ceratite marls, containing abundant fossil. The upper ceratite sandstone is characterised by the presence of flemingites flemingianus, which can be correlated with the flemingites rohilla zone of painkhanda. Above the ceratite sandstone is the upper ceratite limestone composed of hard limestone and intercalated grey marls with highly ornamented ceratites of the genera sibirites, stephanites, etc.
Kashmir
The Himalayan Triassic belt extrend into Kashmir and occurs in the sind and lidar valley, wardwan, gurais and central ladakh and also in northweast Kashmir and pir panjal the trias occurs as along thin band extending from Kashmir on the east to tosh maidan beyond the Jhelum valley on the west. In northweast Kashmir only the upper tries is seen. Jaw fragmant of labyrinthodont amphibian were found from the nodular limestone (middle trias) of pastannah area in Kashmir region and their widespread distribution during the Triassic in india.
Lower Triassic: all the three ammonite zones of lower Triassic, the otoceras, ophiceras and the meekoceras are developed in the vihi area of Kashmir. Though poorly exposed, the exposure at nagburn consists of calcareous nodules overlying a thin band of black shales followed by 90 m bedded blue limestone.
Middle Triassic: lower Triassic limestone are overlain by buff- coloured, thin-bedded limestone with thin intercalation of sandy limestone and shale with a 30 m thick grey thin-bedded limestone at the the base, containing bivalves. These are overlain by nodular limestones and red and grey slaty limeston, rich in cephalopod fossils. These limestone are exposed in pastannah, khrew in vishi and batsuzi.
Upper Triassic: Upper Triassic limestone cover a much wider area, with a few thousand metres thickness, than the lower and middle units. Both megalodon and halobia limestone of upper Triassic of spiti area represented in Kashmir. The upper Triassic limestone are exposed in anantanag district, east and west of wular lake, tosh maidan-gulmargh-golabgarh section, and shams abari area.
The exposures of lower, middle, and upper Triassic limestone are seen together in pahalgam area andsoutheast of wular lake.
