scholarly journals Isostatic residual gravity map of the Santa Ana 1:100,000 scale quadrangle, California

1991 ◽  
Author(s):  
Victoria E. Langenheim ◽  
R.H. Chapman ◽  
R.F. Sikora ◽  
D.A. Ponce ◽  
E.T. Dixon
Geophysics ◽  
2005 ◽  
Vol 70 (1) ◽  
pp. J13-J24 ◽  
Author(s):  
A. Vasanthi ◽  
K. Mallick

The Narayanpet Kimberlite field, that lies southwest of Hyderabad, the capital city of Andhra Pradesh, India, hosts a number of kimberlite pipes. These pipes appear to be randomly positioned. However, based on regional geologic structures revealed by Bouguer gravity anomalies, especially in a regional gravity map, their locations form a definite pattern. In the Narayanpet-Maddur region, regional Bouguer gravity contours exhibit some features of geologic interest: (1) the eastward convex regional contours show an increase in convexity from the Maddur and Kotakonda area on the east to Narayanpet on the west, (2) convexity is maximum in the vicinity of Narayanpet, where a large number of Kimberlite pipes occur nearly parallel to the regional contour, and (3) between Narayanpet and the Maddur-Kotakonda region, kimberlite pipes occur at intersections of three eastward, convex concentric zones with four lineaments, one trending northeast-southwest and the other three nearly east-west. These linear trends are believed to be radial, extensional, deep-fracture zones, through which kimberlite magma erupted about 1100 Ma. Modeling the residual gravity anomaly over one of the four profiles shows fairly good agreement between observed and computed fields. Based on analysis of Bouguer gravity anomalies and modeling of the residual gravity field, likely locations for kimberlite pipes are the contact zones between granite plutons and the country rocks that coincide with the northeast-southwest–trending radial faults that pass through Narayanpet and Kotakonda to the south and through Kazipur to the north.


1987 ◽  
Author(s):  
Alexander Wagini ◽  
Peter Steinhauser ◽  
Bruno Meurers
Keyword(s):  

Geophysics ◽  
1949 ◽  
Vol 14 (1) ◽  
pp. 39-56 ◽  
Author(s):  
W. Raymond Griffin

A precise definition of residual gravity is given and in a form most suitable for numerical application. Some pains are taken to show that the residual‐gravity picture one obtains depends on the method used in obtaining it and that there are many ways in which this may be done. Several examples from actual work on developed oil fields are given in the form of figures and maps to bear out the above statement. Conclusions are drawn as to the relative order of sensitivity of several factors entering into the computations in determining a given residual picture. Factors considered in this paper are (1) size of unit figure, (2) kind (or shape) of unit figure, (3) density of reference net; that is, number of reference points per unit area, and (4) sensitivity of reference points to lateral displacement on gravity map.


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