« PreviousContinue »
into Uri district and Punch. They are unfossiliferous, strongly cleaved, black slates. The peaks of Mar Pathri (11,639 feet) and Khan Pathri (12,504 feet) are composed of these Dogra slates, whose thickness must be large.
The next higher series is the Tanawal1, a strongly arenaceous series also apparently unfossiliferous, which overlies the Dogras unconformably. A basal conglomerate is developed in the Tanawals at their junction with the Dogras west of Chormargi (34° 6′ : 74° 16′). The Tanawals strike north-west and south-east near the junction of sheets 43 J/8 and 4 and then, as they are followed towards and into 43 K/5, the strike becomes more southerly and the width of outcrop greatly increased. There is evidence of much folding in the Tanawals in the higher reaches of the Ferozpur Nala and the increased width of outcrop is due to repetition by folding. The Tanawals extend southwards into Punch and north-west into the Uri district, Kashmir. They must be several thousands of feet thick. At times the quartzites are felspathic. The high peak of Al Pathri (13,938 feet) is formed of Tanawals.
Generally the Tanawals seem to pass up more or less gradually into the Agglomeratic Slate. This is especially noticeable on the ridge connecting Al Pathri with Apharwat (13,592 feet), where the Agglomeratic Slate gets finer in grain and less siliceous as Apharwat is approached. Middlemiss2 has recorded Gondwana plants from this locality. A rather coarse agglomerate is usually present and in this are fragments of Tanawal rocks which presumably were blown out by a large volcanic outburst that heralded the outpouring of the immense masses of Panjal trap. The Agglomeratic Slate conformably underlies the Panjal trap. It is apparently only a few hundreds of feet in thickness. It is faulted near Ningan Dor (34° 3′ 74° 18′) and its outcrop is frequently masked by screes on the Apharwat ridge. It could not be traced in the valley of the Kubnai stream to the north-west of Washtu (11,027 feet). It crosses the Ferozpur Nala striking S. S. E., and then makes a right-angled change in strike under Hadibal (13,663 feet) and the other trap hills to the south-west. Advantage has been taken of its relative softness where the Chor Panjal pass crosses into Punch. The dip near Hadibal is about 15° to the south-east.
1 D. N. Wadia, Rec. Geol. Surv. Ind., LXVIII, Ft. 2, p. 147, (1934). 2 On, cit., XLI, Pt. 2, p. 132, (1911).
Reference has been made in the petrological section of this Report to specimens of unusual basicity and acidity collected by Dr. Coulson from the Panjal trap suite in the Baramula district. Middlemiss1 has already referred to the problems awaiting solution regarding this very interesting suite of rocks. There is an immense thickness (several thousands of feet) of trap in the ridge behind Gulmarg, the base of which is not shown. Extrusion of basic lava, presumably beneath the sea, was followed by a long continued succession of explosive outbursts, the materials of which were stratified as tuffs. Associated with this phase of explosive activity were outpourings of more acid lava, toscanitic in nature. These have since completely devitrified and, like the tuffs and the Panjal trap itself, many have been epidotised. Another form of alteration in the Panjal trap is the development of a tremolitic hornblende. Zoisitisation, chloritisation, and, to a lesser extent, serpentinisation, also have taken place. Mention has been made of the schistosity of certain tuffs which resemble Salkhala rocks. South of Ferozpur Nala, the dips of the Panjal trap are considerably flatter and the highest peaks of the Pir Panjal, including Shin Mahinyu, 15,113 feet, are composed of shallow-dipping trap. The isolated hill of Washtu, W. N. W. of Gulmarg, and Poshkar hill, east of Ferozpur Nala, are also composed of Panjal trap.
A constant, but narrow, band of what is presumably Upper Trias limestone and associated rocks crops out in the tuffs, running from north-east of Washtu to near Gulmarg, where its outcrop is masked by moraines. The same rocks crop out by Ferozpur Nala and stretch from here south-eastwards to the Basam Gali pass into the Sripartapsinghpura tahsil of the Baramula district. Middlemiss2 mapped a broad syncline of these Upper Trias rocks further to the south-east, near Tosha Maidan. The only fossils found by Dr. Coulson were indeterminate corals from the limestones W. N. W. of Basam Gali. The relations of the Upper Trias to the Panjal trap and tuffs are obscure, on account of the folding to which all have been subjected. Vertical dips are common and overfolding occurs, but it would appear that the Upper Trias rocks lie in a highly compressed syncline and are stratigraphically above the trap. There was less explosive activity in the trap suite to the south-east and here the Trias seems associated with trap rather than tuffs.
1 Pal. Ind., N. S., Vol, XII, pp. 12-16, (1928).
2 Rec. Geol. Surv. Ind., XLI, Pt. 2, p. 129, (1911).
There is a small outcrop of very decomposed biotite-granite on the hill slopes above the Ferozpur Nala near Tangmarg. This granite shows graphic structure. It is apparently brecciated and intrusive into the trap suite and numerous small veins of quartz occur associated with it. This granite is post-Middle Trias, if the tuffs into which it is intruded be taken as that. There are no contacts with the Upper Trias. The granite is probably of the same age as that described by Wadia1 as post-Permian. Another small outcrop occurs south of the Ferozpur Nala near Ringawari (34° 2′ : 74° 28').
Reference has been made in the petrological section of this Report to the relatively fresh, and probably Tertiary, hypersthenedolerite cropping out in the bed of the Ferozpur Nala near Tangmarg. This is obviously much younger than the Panjal trap suite. It is apparently overlain by Karewas.
Dr. Coulson collected numerous plant fossils from beds of Karewas near Linyan (34° 4' 74° 17') on the banks of Ningle Nala at a height of about 9,500 feet, but so far these have not been identified. Another high-level outcrop of Karewas is near Chormargi. Middlemiss2 recorded plant fossils from other localities in the Karewas and has referred to the immense post-Karewa dislocations and uplift by which these Karewa beds now occur at high levels in the Pir Panjal. The general dip of the Karewas in the foothills of the Gulmarg area is away from the Pir Panjal towards the Vale of Kashmir. The Karewas in part at least are contemporaneous with the Pleistocene glaciation to which the area was subjected.
Apart from Recent alluvium, the youngest deposits in Dr. Coulson's area are the large masses of scree and moraine material which frequently obscure the solid geology.
107. Mr. J. B. Auden joined the Shaksgam Expedition, under the leadership of Mr. E. Shipton, as geologist. The party of four Europeans left Srinagar on May 5th, following the route over the Zoji La to Askole, and crossing a new pass over the Karakoram Range leading from the Trango branch of the Baltoro glacier to the Sarpo Laggo glacier. Survey work was carried out down the Sarpo Laggo to the Shaksgam river, over the Aghil range by the Aghil Dawan, and
Karakoram, Shaksgam, Aghil.
1 Rec. Geol. Surv. Ind., LXVIII, Pt. 2, p. 169, (1934).
2 Op. cit., XLI, Pt. 2, pp. 121-122, (1911).
a Op. cit., pp. 136-137.
northwards up to the Yarkand River. Returning to the Sarpo Laggo, the Crevasse glacier, first discovered by Younghusband, was examined to its head, after which Mr. Auden crossed the Karakoram watershed into the Punmah, and returned alone to Askole. He reached Srinagar on September 4th via the Deosai plains. Until the topographical maps made by Mr. M. A. Spender, with the assistance of Messrs. Shipton, Tilman and Auden, have been prepared, it is impossible to make an accurate geological sketch map of the area traversed. Difficulties inherent in such a mountainous, and for the most part unsurveyed, country naturally prevented any detailed geological mapping being carried out. This area is included within maps 42 P, 43 M, 51 D (unpublished) and 52 A.
The sequence determined by Mr. Auden is as follows:
Mesozoic (marine Trias and Jurassic),
Permo-Carboniferous (mostly marine),
Sarpo Laggo series of slates, phyllites, schists, quartzites, greywackés, impure limestones.
The fossils collected by him, which will be described by Dr. M. R. Sahni, indisputably prove the existence of Jurassic and PermoCarboniferous beds. The latter had previously been found along the Shaksgam by Professor Ardito Desio in 1929.1 The Mesozoic limestones occupy a tectonic basin 16 miles in length, mostly along the southern Aghil range. These limestones are surrounded by the Permo-Carboniferous, which is well exposed along the Shaksgam valley, and up the west Surukwat river north of the Aghil pass. The underlying Sarpo Laggo series crops out extensively along the Sarpo Laggo glacier, up the Crevasse glacier, and among the northern Aghil ranges, extending northwards to the Yarkand River. They also clearly form a considerable portion of the Kun Lun mountains in Chinese Turkestan. Their age is considered to be mostly lower Palæozoic. A synclinal zone of red beds was found crossing the Surukwat river and extending up the Zug Shaksgam. These are possibly equivalent to the Tisnab beds of De Terra.2
There is no doubt from Auden's work, and the work of Desio in 1929, Hayden in the Pamirs in 1914, and De Terra in the Depsang in 1928, that a zone of marine Tethys sediments extends for many
1 Geog. Journ. LXXV, p. 402, (1930).
2 Geologische Forschungen im westlichen K'un Lun und Karakoram-Himalaya, pp. 51, 81, (1932).
miles just north of the Karakoram range. The northern boundary of the marine Mesozoic rocks must have been along the Kun Lun Range.
South of the Karakoram watershed there is a marked increase in metamorphism, and Mr. Auden now believes, with Desio, that some of the meso-grade para-gneisses of the Punmah and Biafo glaciers, around Askole, and along the Shigar river, are largely altered representatives of a Palæozoic series, including even the
The sedimentary rocks have been invaded by granodiorites, dolerites and lamprophyres. The dolerites occur mostly among the northern Aghil ranges, while the lamprophyres are best developed along a zone between the Karakoram watershed and the Shaksgam, being abundant just north of K2 peak. Both granites and lamprophyres are post-Permo-Carboniferous. The granites are probably derived from the same magma as was intruded along the Indus
Young volcanic rocks, almost certainly of Cretaceous-Eocene age, are found extensively across the Deosai plains.
108. At the beginning of the field-season 1936-37, Mr. P. C. Das Hazra spent about four weeks with Mr. H. M. Lahiri in the Hoshiarpur and Kangra districts in studying and mapping the Siwalik rocks along the HoshiarpurDharmsala road section. On the conclusion of this reconnaissance work, Mr. Das Hazra left to commence his systematic survey of the Tertiaries of the Jammu hills in the Udhampur district of Jammu and Kashmir. The area surveyed during the season is comprised in one inch to one mile sheet 43 P/1 and portions of sheets 43 P/2 and 43 L/13.
In the old maps of the Sub-Himalayas, the Tertiaries of this area are divided into Mari, Lower and Upper Siwaliks; but Mr. Das Hazra, following Pilgrim's classification, has recognised and mapped the following formations:
Sub-Recent and Recent deposits.
Udhampur and Jammu districts, Jammu,
(Boulder Conglomerate stage
1 Rec. Geol. Surv. Ind., IX, pp. 49, 155, (1876).
2 Op. cit., XL, pp. 185-205, (1910).