Preliminary Geology And Petrography Of Swat Kohistan

Age and Correlation : The Gabral rocks exhd into Dir in the west, they
may be merging into Deshai diorites in the nortbeestern parts. Mineralogjcally,
some of them (the diorites) are similar to those of Desbni, however, they
generally lack the strong foliation which is so characteristic of the Deshai
diorites. Thus, they are most probably younger than the Deshai ones. It has
already been stated that the diorites clearly intrude the volcnnic rooka near
Gahal, and are themselves intruded by various types of granities. Therefore,
it appears that the rocks may be spread over a broader range of Lo~ver to Niddle
Tertiary period.
The Granitic Rocks.
Apart from the smaller granite intrusions described in the previous pages,
large masses of granites occur in Bankhwar, Matiltan ares, and Dewangar. The
first two are of the size of stock and are so much similar in appearance and
mineral composition tlhat they may be the intrusions of the same magma. They
are named by us as the Matiltan Granite. The last one, judging from the
traverse of Matsushita (1965, p. 45) along Dewangar Pass, may be of batholithic
dimenaion and is named as the Dewangar Granite.
The Matiltan Granite : These rocks are light-coloured, with a flesh-pink
touch. They are well - jointed and, at places, foliated, especially in the
Bankhwar where their foliation trends notheast, clipping northwest. Out of the
many well-developed joint sets, the best one strikes N 85' - 60•‹E, with
northwesterly dips. Along this joint set, the granite looks "bedded" from a.
distance due to well-developed transverse joints. Aleo, in Bankhwar, steep
cliffs of great height are characteris tic. The fdintion appears to inoreese
northwards. Some of the rocks are porphyritic, with two to three millimetrea
long, lenticular feldspars in w finer groundmass.
The exposures in Matiltan cover a Isrger area and extend up to Falakser.
Around Makiltan, abundant granite intrusions are seen along the streams under
a qoa$tzite cover. Some of the intrusions seem to be marginally chilled. In
Badshwar and near Pdoga, they clearly intrude the volcanic and dioritic rocks
with sharp margins. At places, they are repeated in short distances. Xenolitlbs
of amphibolites, quartzites, and diorites are common; more rarely, thin layers
of the former two also occur. In Batnndar Stream, where the main rocks are
volcanic; abundant veins of granite, at places in network, seemingly extend
from the adjacent plutoa in lhnkhmar. TTeins of quartz and less common.
apIit;es, up to six inches thick, occur throughout. Along cartsia fractures,
yellow apidote and feldspar fillings are also present,