S. Farooq, Dept of Geology AMU


S. Farooq Department of Geology Aligarh Muslim University email farooq.amu@gmail.com	Geology
The Jhalawar area forms the south western peripheral part of the Vindhyans of Rajasthan. In this area, an interlayered sequence of shales, limestones and sandstones of the Lower and Upper Vindhyans forms a major anticlinal structure, known as the Jhalawar Anticline (see the geological map) with its axial trace trending in a NW-SE direction. Due to subsequent erosion, the older formations are exposed at the core and successively younger horizons lie on either sides of the axis. Structural features observed in the rock formations viz. parallel geometry of the folds and nearly uniform orthogonal thickness of beds suggest that the regional structure followed the pattern of flexural slip fold mechanism. This can be verified during the field trip when you will observe: The absence of axial plane cleavage Development of folds on bedding surfaces Rounded hinges of folds, and Wide spacing between glide surfaces Using satellite imagery and airphoto interpretation and ground truth verification, Ramasamy and Bakliwal (1988) interpreted the lithology and lineaments in a vast area around Jhalawar. These data were analyzed for evaluation of tectonic evolution abd resource potential of the area. The Jhalawar anticline displays a wide ranging azimuthal frequency of lineaments of lengths rabging from a few km to several 10s of km. The azimuthal frequency plots made by Ramasamy and Bakliwal (1988) show that these fall under two groups with their mean orientations in N 43o W – S 43o E, and N 48o E – S 48o W directions. In satellite images these are visible as dark linear streaks at low zoom levels, but may be seen to contain prolific vegetation when viewed at higher zoom levels. It can be seen in the north and north-east of Jhalawar town that the kali Sindh River, which generally flows in a northerly direction in the area, takes several sharp bends towards northwest as it crosses the northeastern limb of the Jhalawar anticline, flows for a kilometer or two, takes a sharp bend towards north, continues for a few km and again bends NW. This is unequivocal evidence (perhaps a classical example) of a river following a fault line. When you go to the field: Look for evidences of faulting (fault breccia, gouge, slickensides etc) Try and work out all parameters if the faults (displacement direction, magnitude etc) REFERENCES: Ramasamy, S.M. and Bakliwal, P.C.. 1988. Use of remote sensing and lineament analysis for tectonic evolution and resource study of a part of Vindhyan Basin, Jhalawar area, India. Journal of the Indian Society of Remote Sensin Determining strike and dip in Google Earth View a low resolution geological map of Jhalawar area in Google Earth View the localities map of the area around Jhalawar town in Google Earth General Information about Jhalawar Places of tourist interest in and around Jhalawar

S. Farooq
Department of Geology
Aligarh Muslim University

Geology

The Jhalawar area forms the south western peripheral part of the Vindhyans of Rajasthan. In this area, an interlayered sequence of shales, limestones and sandstones of the Lower and Upper Vindhyans forms a major anticlinal structure, known as the Jhalawar Anticline (see the geological map) with its axial trace trending in a NW-SE direction. Due to subsequent erosion, the older formations are exposed at the core and successively younger horizons lie on either sides of the axis.

Structural features observed in the rock formations viz. parallel geometry of the folds and nearly uniform orthogonal thickness of beds suggest that the regional structure followed the pattern of flexural slip fold mechanism. This can be verified during the field trip when you will observe:

The absence of axial plane cleavage
Development of folds on bedding surfaces
Rounded hinges of folds, and
Wide spacing between glide surfaces

Using satellite imagery and airphoto interpretation and ground truth verification, Ramasamy and Bakliwal (1988) interpreted the lithology and lineaments in a vast area around Jhalawar. These data were analyzed for evaluation of tectonic evolution abd resource potential of the area.

The Jhalawar anticline displays a wide ranging azimuthal frequency of lineaments of lengths rabging from a few km to several 10s of km. The azimuthal frequency plots made by Ramasamy and Bakliwal (1988) show that these fall under two groups with their mean orientations in N 43o W – S 43o E, and N 48o E – S 48o W directions. In satellite images these are visible as dark linear streaks at low zoom levels, but may be seen to contain prolific vegetation when viewed at higher zoom levels.

It can be seen in the north and north-east of Jhalawar town that the kali Sindh River, which generally flows in a northerly direction in the area, takes several sharp bends towards northwest as it crosses the northeastern limb of the Jhalawar anticline, flows for a kilometer or two, takes a sharp bend towards north, continues for a few km and again bends NW. This is unequivocal evidence (perhaps a classical example) of a river following a fault line. When you go to the field:

Look for evidences of faulting (fault breccia, gouge, slickensides etc)
Try and work out all parameters if the faults (displacement direction, magnitude etc)

REFERENCES:
Ramasamy, S.M. and Bakliwal, P.C.. 1988. Use of remote sensing and lineament analysis for tectonic evolution and resource study of a part of Vindhyan Basin, Jhalawar area, India. Journal of the Indian Society of Remote Sensin

Determining strike and dip in Google Earth

View a low resolution geological map of Jhalawar area in Google Earth

View the localities map of the area around Jhalawar town in Google Earth

General Information about Jhalawar
Places of tourist interest in and around Jhalawar