GEOLOGY AND MINERAL RESOURCES
~Extent of Geological Record.~--Although the main part of the Panjáb plain
is covered by a mantle of comparatively recent alluvium, the provinces
described in this book display a more complete record of Indian
geological history than any other similar area in the country. The
variety is so great that no systematic or sufficient description could
be attempted in a short chapter, and it is not possible, therefore, to
do more in these few pages than give brief sketches of the patches of
unusual interest.
~Aravallí System.~--In the southern and south-eastern districts of the
Panjáb there are exposures of highly folded and metamorphosed rocks
which belong to the most ancient formations in India. These occupy the
northern end of the Aravallí hills, which form but a relic of what must
have been at one time a great mountain range, stretching roughly
south-south-west through Rájputána into the Bombay Presidency. The
northern ribs of the Aravallí series disappear beneath alluvial cover in
the Delhi district, but the rocks still underlie the plains to the west
and north-west, their presence being revealed by the small promontories
that peep through the alluvium near the Chenáb river, standing up as
small hills near Chiniot in the Sháhpur, Jhang, and Lyallpur districts.
The Salt Range in the Jhelam and Sháhpur districts, with a western
continuation in the Mianwálí district to and beyond the Indus, is the
most interesting part of the Panjáb to the geologist. It contains
notable records of three distinct eras in geological history. In
association with the well-known beds of rock-salt, which are being
extensively mined at Kheora, occur the most ancient fossiliferous
formations known in India, corresponding in age with the middle and
lower part of the Cambrian system of Europe. These very ancient strata
immediately overlie the red marls and associated rock-salt beds, and it
is possible that they have been thrust over bodily to occupy this
position, as we have no parallel elsewhere for the occurrence of great
masses of salt in formation older than the Cambrian.
The second fragment of geological history preserved in the Salt Range is
very much younger, beginning with rocks which were formed in the later
part of the Carboniferous period. The most remarkable feature in this
fragment is a boulder-bed, resting unconformably on the Cambrian strata
and including boulders of various shapes and sizes, which are often
faceted and striated in a way indicative of glacial action. Several of
the boulders belong to rocks of a peculiar and unmistakable character,
such as are found _in situ_ on the western flanks of the Aravallí Range,
some 750 miles to the south. The glacial conditions which gave rise to
these boulder-beds were presumably contemporaneous with those that
produced the somewhat similar formation lying at the base of the great
coal-bearing system in the Indian peninsula. The glacial boulder-bed
thus offers indirect evidence as to the age of the Indian coal-measures,
for immediately above this bed in the Salt Range there occur sandstones
containing fossils which have affinities with the Upper Carboniferous
formations of Australia, and on these sandstones again there lie
alternations of shales and limestones containing an abundance of fossils
that are characteristic of the Permo-Carboniferous rocks of Russia.
These are succeeded by an apparently conformable succession of beds of
still younger age, culminating in a series of shales, sandstones, and
limestones of unmistakably Triassic age.
There is then an interruption in the record, and the next younger series
preserved occurs in the western part of the Salt Range as well as in the
hills beyond the Indus. This formation is of Upper Jurassic age,
corresponding to the well-known beds of marine origin preserved in
Cutch. Then follows again a gap in the record, and the next most
interesting series of formations found in the Salt Range become of great
importance from the economic as well as from the purely scientific point
of view; these are the formations of Tertiary age.
The oldest of the Tertiary strata include a prominent limestone
containing Nummulitic fossils, which are characteristic of these Lower
Tertiary beds throughout the world. Here, as in many parts of
North-Western India, the Nummulitic limestones are associated with coal
which has been largely worked. The country between the Salt Range
plateau and the hilly region away to the north is covered by a great
stretch of comparatively young Tertiary formations, which were laid down
in fresh water after the sea had been driven back finally from this
region. The incoming of fresh-water conditions was inaugurated by the
formation of beds which are regarded as equivalent in age to those known
as the Upper Nari in Sind and Eastern Baluchistán, but the still later
deposits, belonging to the well-known Siwálik series, are famous on
account of the great variety and large size of many of the vertebrate
fossil remains which they have yielded. In these beds to the north of
the Salt Range there have been found remains of Dinotherium, forms
related to the ancestors of the giraffe and various other mammals, some
of them, like the Sivatherium, Mastodon, and Stegodon, being animals of
great size. On the northern side of the Salt Range three fairly
well-defined divisions of the Siwálik series have been recognised, each
being conspicuously fossiliferous--a feature that is comparatively rare
in the Siwálik hills further to the south-east, where these rocks were
first studied. The Siwálik series of the Salt Range are thus so well
developed that this area might be conveniently regarded as the type
succession for the purpose of correlating isolated fragmentary
occurrences of the same general series in northern and western India. To
give an idea as to the age of these rocks, it will be sufficient to
mention that the middle division of the series corresponds roughly to
the well-known deposits of Pikermi and Samos.
~Kashmir~ deserves special mention, as it is a veritable paradise for the
geologist. Of the variety of problems that it presents one might mention
the petrological questions connected with the intrusion of the great
masses of granite, and their relation to the slates and associated
metamorphic rocks. Of fossiliferous systems there is a fine display of
material ranging in age from Silurian to Upper Trias, and additional
interest is added by the long-continued volcanic eruptions of the
"Panjál trap." Students of recent phenomena have at their disposal
interesting problems in physiography, including a grand display of
glaciers, and the extensive deposits of so-called _karewas_, which
appear to have been formed in drowned valleys, where the normal
fluviatile conditions are modified by those characteristic of lakes. The
occurrence of sapphires in Zánskar gives the State also an interest to
the mineralogist and connoisseur of gem-stones.
Of this kaleidoscopic assemblage of questions the ones of most immediate
interest are connected with the Silurian-Trias succession in the Kashmír
valley, for here we have a connecting-link between the marine formations
of the Salt Range area and those which are preserved in greater
perfection in Spití and other parts of the Tibetan highlands, stretching
away to the south-east at the back of the great range of crystalline
snow-covered peaks.
In this interesting part of Kashmír the most important feature to Indian
geologists is the occurrence of plant remains belonging to genera
identical with those that occur in the lower part of the great
coal-bearing formation of Peninsular India, known as the Gondwána
system. Until these discoveries were made in Kashmír about ten years ago
the age of the base of the Gondwánas was estimated only on indirect
evidence, partly due to the assumption that glacial conditions in the
Salt Range and those at the base of the Gondwánas were contemporaneous,
and partly due to analogy with the coal measures of Australia and South
Africa. In Kashmír the characteristic plant remains of the Lower
Gondwánas are found associated with marine fossils in great abundance,
and these permit of a correlation of the strata with the upper part of
the Carboniferous system of the European standard stratigraphical scale.
Kashmír seems to have been near the estuary of one of the great rivers
that formerly flowed over the ancient continent of _Gondwánaland_ (when
India and South Africa formed parts of one continental mass) into the
great Eurasian Ocean known as _Tethys_. As the deposits formed in this
great ocean give us the principal part of our data for forming a
standard stratigraphical scale, the plants which were carried out to sea
become witnesses of the kind of flora that flourished during the main
Indian coal period; they thus enable us with great precision to fix the
position of the fresh-water Gondwánas in comparison with the marine
succession.
~Spití.~--With á brief reference to one more interesting patch among the
geological records of this remarkable region, space will force us to
pass on to consideration of minerals of economic value. The line of
snow-covered peaks, composed mainly of crystalline rocks and forming a
core to the Himálaya in a way analogous to the granitic core of the
Alps, occupies what was once apparently the northern shore of
Gondwánaland, and to the north of it there stretched the great ocean of
Tethys, covering the central parts of Asia and Europe, one of its
shrunken relics being the present Mediterranean Sea. The bed of this
ocean throughout many geological ages underwent gradual depression and
received the sediments brought down by the rivers from the continent
which stretched away to the south. The sedimentary deposits thus formed
near the shore-line or further out in deep water attained a thickness of
well over 20,000 feet, and have been studied in the _tahsíl_ of Spití,
on the northern border of Kumáon, and again on the eastern Tibetan
plateau to the north of Darjeeling. A reference to the formations
preserved in Spití may be regarded as typical of the geological history
and the conditions under which these formations were produced.
~Succession of Fossiliferous Beds.~--In age the fossiliferous beds range
from Cambrian right through to the Tertiary epoch; between these
extremes no single period was passed without leaving its records in some
part of the great east-to-west Tibetan basin. At the base of the whole
succession there lies a series of schists which have been largely
metamorphosed, and on these rest the oldest of the fossiliferous series,
which, on account of their occurring in the region of snow, has been
named the _Haimanta system_. The upper part of the Haimanta system has
been found to contain the characteristic trilobites of the Cambrian
period of Europe. Over this system lie beds which have yielded in
succession Ordovician and Silurian fossils, forming altogether a compact
division which has been distinguished locally as the _Muth system_. Then
follows the so-called _Kanáwar system_, which introduces Devonian
conditions, followed by fossils characteristic of the well-known
mountain limestone of Europe.
Then occurs a break in the succession which varies in magnitude in
different localities, but appears to correspond to great changes in the
physical geography which widely affect the Indian region. This break
corresponds roughly to the upper part of the Carboniferous system of
Europe, and has been suggested as a datum line for distinguishing in
India an older group of fossiliferous systems below (formed in an area
that has been distinguished by the name _Dravidian_), from the younger
group above, which has been distinguished by the name _Aryan_.
During the periods that followed this interruption the bed of the great
Eurasian Ocean seems to have subsided persistently though
intermittently. As the various sediments accumulated the exact position
of the shore-line must have changed to some extent to give rise to the
conditions favourable for the formation at one time of limestone, at
another of shale and at other times of sandy deposits. The whole column
of beds, however, seems to have gone on accumulating without any folding
movements, and they are consequently now found lying apparently in
perfect conformity stage upon stage, from those that are Permian in age
at the base, right through the Mesozoic group, till the time when
Tertiary conditions were inaugurated and the earth movements began which
ultimately drove back the ocean and raised the bed, with its accumulated
load of sediments, into the great folds that now form the Himálayan
Range. This great mass of Aryan strata includes an enormous number of
fossil remains, giving probably a more complete record of the gradual
changes that came over the marine fauna of Tethys than any other area of
the kind known. One must pass over the great number of interesting
features still left unmentioned, including the grand architecture of the
Sub-Himálaya and the diversity of formations in different parts of the
Frontier Province; for the rest of the available space must be devoted
to a brief reference to the minerals of value.
~Rock-salt~, which occurs in abundance, is possibly the most important
mineral in this area. The deposits most largely worked are those which
occur in the well-known Salt Range, covering parts of the districts of
Jhelam, Sháhpur, and Mianwálí. Near the village of Kheora the main seam,
which is being worked in the Mayo mines, has an aggregate thickness of
550 feet, of which five seams, with a total thickness of 275 feet,
consist of salt pure enough to be placed on the table with no more
preparation than mere pulverising. The associated beds are impregnated
with earth, and in places there occur thin layers of potash and
magnesian salts. In this area salt quarrying was practised for an
unknown period before the time of Akbar, and was continued in a
primitive fashion until it came under the control of the British
Government with the occupation of the Panjáb in 1849. In 1872 systematic
mining operations were planned, and the general line of work has been
continued ever since, with an annual output of roughly 100,000 tons.
Open quarries for salt are developed a short distance to the
east-north-east of Kálabágh on the Indus, and similar open work is
practised near Kohát in the North West Frontier Province, where the
quantity of salt may be regarded as practically inexhaustible. At
Bahádur Khel the salt lies at the base of the Tertiary series, and can
be traced for a distance of about eight miles with an exposed thickness
of over 1000 feet, sometimes standing up as hills of solid salt above
the general level of the plains. In this area the production is
naturally limited by want of transport and the small local demand, the
total output from the quarries being about 16,000 tons per annum. A
small quantity of salt (generally about 4000 tons a year), is raised
also from open quarries in the Mandí State, where the rock-salt beds,
distinctly impure and earthy, lie near the junction between Tertiary
formations and the older unfossiliferous groups.
~Coal~ occurs at numerous places in association with the Nummulitic
limestones of Lower Tertiary age, in the Panjáb, in the North West
Frontier Province, and in the Jammu division of Kashmír. The largest
output has been obtained from the Salt Range, where mines have been
opened up on behalf of the North Western Railway. The mines at Dandot in
the Jhelam district have considerable fluctuations in output, which,
however, for many years ranged near 50,000 tons. These mines, having
been worked at a financial loss, were finally abandoned by the Railway
Company in 1911, but a certain amount of work is still being continued
by local contractors. At Bháganwála, 19 miles further east, in the
adjoining district of Sháhpur, coal was also worked for many years for
the North Western State Railway, but the maximum output in any one year
never exceeded 14,000 tons, and in 1900, owing to the poor quality of
material obtained, the collieries were closed down. Recently, small
outcrop workings have been developed in the same formation further west
on the southern scarp of the Salt Range at Tejuwála in the Sháhpur
district.
~Gold~ to a small amount is washed from the gravel of the Indus and some
other rivers by native workers, and large concessions have been granted
for systematic dredging, but these enterprises have not yet reached the
commercially paying stage.
~Other Metals.~--Prospecting has been carried on at irregular intervals in
Kulu and along the corresponding belt of schistose rocks further west in
Kashmír and Chitrál. The copper ores occur as sulphides along certain
bands in the chloritic and micaceous schists, similar in composition and
probably in age to those worked further east in Kumáon, in Nipál, and in
Sikkim. In Lahul near the Shigrí glacier there is a lode containing
~antimony~ sulphide with ores of ~zinc~ and ~lead~, which would almost
certainly be opened up and developed but for the difficulty of access
and cost of transport to the only valuable markets.
~Petroleum~ springs occur among the Tertiary formations of the Panjáb and
Biluchistán, and a few thousand gallons of oil are raised annually.
Prospecting operations have been carried on vigorously during the past
two or three years, but no large supplies have so far been proved. The
principal oil-supplies of Burma and Assam have been obtained from rocks
of Miocene age, like those of Persia and the Caspian region, but the
most promising "shows" in North West India have been in the older
Nummulitic formations, and the oil is thus regarded by some experts as
the residue of the material which has migrated from the Miocene beds
that probably at one time covered the Nummulitic formations, but have
since been removed by the erosive action of the atmosphere.
~Alum~ is manufactured from the pyritous shales of the Mianwálí district,
the annual output being generally about 200 to 300 tons. Similar shales
containing pyrites are known to occur in other parts of this area, and
possibly the industry might be considerably extended, as the annual
requirements of India, judged by the import returns, exceed ten times
the native production of alum.
~Borax~ is produced in Ladákh and larger quantities are imported across
the frontier from Tibet. In the early summer one frequently meets herds
of sheep being driven southwards across the Himalayan passes, each sheep
carrying a couple of small saddle-bags laden with borax or salt, which
is bartered in the Panjáb bazars for Indian and foreign stores for the
winter requirements of the snow-blocked valleys beyond the frontier.
~Sapphires.~--The sapphires of Zánskar have been worked at intervals since
the discovery of the deposit in 1881, and some of the finest stones in
the gem market have been obtained from this locality, where work is,
however, difficult on account of the great altitude and the difficulty
of access from the plains.
~Limestone.~--Large deposits of Nummulitic limestone are found in the
older Tertiary formations of North-West India. It yields a pure lime and
is used in large quantities for building purposes. The constant
association of these limestones with shale beds, and their frequent
association with coal, naturally suggest their employment for the
manufacture of cement; and special concessions have recently been given
by the Panjáb Government with a view of encouraging the development of
the industry. The nodular impure limestone, known generally by the name
of _kankar_, contains sufficient clay to give it hydraulic characters
when burnt, and much cement is thus manufactured. The varying
composition of _kankar_ naturally results in a product of irregular
character, and consequently cement so made can replace Portland cement
only for certain purposes.
~Slate~ is quarried in various places for purely local use. In the Kángra
valley material of very high quality is obtained and consequently
secures a wide distribution, limited, however, by competition with
cheaply made tiles.
~Gypsum~ occurs in large quantities in association with the rock-salt of
the Salt Range, but the local demand is small. There are also beds of
potash and magnesian salts in the same area, but their value and
quantity have not been thoroughly proved.
[Illustration: January-February.]
[Illustration: March to May.]
_Normal Rainfall._
I. N.W.F. Province. II. Kashmir.
III. Panjáb E. and N. IV. Panjáb S.W.
Fig. 16. Rainfall of different Seasons.
[Illustration: June to September.]
[Illustration: October to December.]
_Normal Rainfall._
I. N.W.F. Province II. Kashmir.
III. Panjáb E. and N. IV. Panjáb S.W.
Fig. 16 (_cont._). Rainfall of different Seasons.