this copy of my paper on economic geology of sandstone deposits of Barmer in Rajasthan state

1. OCCURRENCES OF SANDSTONE SUITABLE AS BUILDING
STONE AND FOR CARVING IN BARMER DISTRICT, JODHPUR
M. S. Sisodia, G. Lashkari & R. G. Goswami*
Department of Geology, J. N. Vyas University, Jodhpur. 342 005
*Department of Mines and Geology, Government of Rajasthan, Jodhpur.
Abstract
Sandstone leases have been allotted by the Rajasthan state government in thirteen districts of
Rajasthan, but no lease of sandstone to be mined as building stone or for other similar
purposes has been allotted in whole of the Barmer district. A few leases allotted in Barmer
district are mostly for masonry stone which are of igneous origin and are used as concrete for
road construction. We report here new occurrences of sandstone in Barmer Basin, some of
these sandstone are thinly bedded, hard, compact, pink colored, fine to coarse grained, quite
suitable as building stone; while some are comparatively soft, flaggy, pale to pink colored that
can be used for carving etc.
Introduction
The sedimentary tract in northwestern Rajasthan covers an area of about 1, 20,000 km2. This
area is subdivided into several basins viz. The Jaisalmer Basin, the Barmer Basin, the Bikaner-
Nagaur Basin and Sanchaur Basin. We mapped Barmer basin basically to deduce the
stratigraphy of the Barmer Basin from the available outcrops and to determine tectonic control
on basin development from kinematic indicators in the basin fill sediments (see Sisodia and
Singh, 2000 for details). The geological map and stratigraphic correlation of Barmer Basin are
given in Figs 1and 2. During the survey of Barmer Basin we came across several sandstone
outcrops which we reckon as promising areas for building stone.
Geology of Barmer Basin
The Barmer Basin comprises mainly middle Jurassic to lower Eocene sediments. The outcrops
are highly scarce as most of them are covered under extensive desert sand. The oldest rocks
exposed in the area belong to the Precambrian Malani Suite of igneous rocks. The formations
of Proterozoic to lower Cambrian age named as Birmania and Randha Formations show their
presence at the western margin of the basin.
Sarnu Formation
The sedimentary rocks overlying the Malani Suite of igneous rocks, with no conformable
contact exposed at Sarnu (N25°40.721' E71°46.028') are designated as Sarnu Formation
(Dasgupta et al.. 1973 in Panday and Dave. 1998). The Sarnu Formation has very restricted
occurrence and does not have wider distribution. The Sarnu Formation is dominantly
comprised of sandstone. This sandstone is hard, whitish, silica-cemented quartz arenite with
occasional quartz pebbles of 2-5 cm diameter. This sandstone cyclically grades into fine
sandstone to siltstone. (Plate 1.a)
Barmer Formation:
The Barmer Formation is about 70 km thick and extends up to twelve km north of Barmer
near Lunu hill. The basal part of the formation comprises reddish, medium to coarse-grained,
lithic quartz sandstone and conglomerate. The upper part of the formation is characterized by
the presence of siltstone, sandstone and conglomerate (Plate 1.b).
Fatehgarh Formation
The sedimentary sequence exposed at Bariyara village (South of Fatehgarh) belongs to the
Fatehgarh Formation. The maximum thickness of Fatehgarh Formation is about 71m at Lordi
Nala. The formation is a thick sequence of coarsening upward sediments. The major part of

2. Fatehgarh Formation comprises soft, parallel-laminated, pinkish-white, and fine to medium
grained sandstone. The top sandstone shows cross-bedding.
Mataji-ka-Dunger Formation
The formation is named after the highest peak (381m), Mataji ka Dungar, near Dharvi Khurd
village (N 24038.2’ E 71019.2’). The lithology of the Mataji-ka-Dunger Formation is
dominantly sandstone, siltstone, and claystone. The maximum thickness of this formation is
about 44m. The formation shows cyclically arranged claystone, siltstone and sandstone.
Sandstone shows considerable variation in grain size. However, no distinct mineralogical
difference is visible. The grain size variation displays three cycles. The lower cycle at Dharvi
Khurd is represented by soft, white, non-calcareous claystone which is overlain by middle-cycle,
poorly cemented, thinly bedded, plane-tabular, cross bedded quartz sandstone and
siltstone. The upper cycle contains brown to dark brown, hard, granular sandstone.
To the NE of Shiv (N 260 06.2’ E 710 12.2’) two outcrops of sandstone are exposed. One type
of sandstone is hard, compact, speckled quartzitic sandstone appearing as rhyolite in the
rhyolite country. The other type of sandstone is very hard, compact, cherty and displays cross-bedding
(Plate 1.c &d).
The younger Akli Formation mostly comprises mudstone, bentonite and lignite. The sandstone
occurs as intercalations.
Acknowledgement:
We are grateful to the local people who acted as guide during our survey of Barmer Basin.
References:
Pandey, J. and Dave, A., (1998). Stratigraphy of Indian Petroliferous Basins. Presidential
Addresss, XVI Indian Coll. Micropal. Strati., Goa, 247 pp.
Sisodia, M. S. and Singh, U. K., (2000). Depositional environment and hydrocarbon prospects
of Barmer Basin, Rajasthan, India. Nafta, 51 (9), 309-326

3. Fig. 1 Geological map of Barmer Basin.

4. Fig. 2 Stratigraphic correlation of successions of different formations of Barmer Basin.
INDEX

7. a
b
c d
Plate 1. (a) Sarnu sandstone, it is thinly bedded, pinkish, fine to coarse grained and
compact.
(b) Soft, fine grained, channel filled Barmer Formation sandstone.
(c) Clean, cross bedded sandstone at top of the cycle of Mataji- ka-Dunger Formation.
(d) Fine, argillaceous sandstone at Kotra Fort.