A new inversion method of estimation of simultaneous near surface bulk density variations and terrain correction across the Bandar Charak (Hormozgan-Iran).

Reza Toushmalani,Azizalah Rahmati

doi:10.1186/2193-1801-3-135

Reza Toushmalani, Azizalah Rahmati

Open Access

https://doi.org/10.1186/2193-1801-3-135

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Abstract

A gravity inversion method based on the Nettleton-Parasnis technique is used to estimate near surface density in an area without exposed outcrop or where outcrop occurrences do not adequately represent the subsurface rock densities. Its accuracy, however, strongly depends on how efficiently the regional trends and very local (terrain) effects are removed from the gravity anomalies processed. Nettleton’s method implemented in a usual inversion scheme and combined with the simultaneous determination of terrain corrections. This method may lead to realistic density estimations of the topographical masses. The author applied this technique in the Bandar Charak (Hormozgan-Iran) with various geological/geophysical properties. These inversion results are comparable to both values obtained from density logs in the mentioned area and other methods like Fractal methods. The calculated densities are 2.4005 gr/cm3. The slightly higher differences between calculated densities and densities of the hand rock samples may be caused by the effect of sediment-filled valleys.

Highlights

Bulk density serves as an important parameter and it is needed to interpret gravity data and determine subsurface structures
The data has been collected in the Bandar Charak area in Hormozgan- Iran
A basic study of the geology of the area, a detail investigation of structural features such as faults associated with the Dehnow anticline, and application of the geophysical techniques, and other exploration methods is necessary to investigate the subsurface extension of the this anticline and to identify salt plug intrusion into the anticline

Summary

Introduction

Bulk density serves as an important parameter and it is needed to interpret gravity data and determine subsurface structures. The researcher determined the estimate of subsurface densities by using an inversion technique based on Nettleton (1939), and Parasnis’s (1952) which has been described in Niti (Mankhemthong et al 2012) The author applied these techniques to analyze the gravity data. A basic study of the geology of the area, a detail investigation of structural features such as faults associated with the Dehnow anticline, and application of the geophysical techniques, and other exploration methods is necessary to investigate the subsurface extension of the this anticline and to identify salt plug intrusion into the anticline. In the Bouguer correction formula, density value that provide the best fit of the Bouguer gravity represents the best estimate of the near surface density Nettleton developed these methods as follow: The relative Bouguer gravity anomaly (ΔBA) between the reference station and any station is ΔBA 1⁄4 ΔGob−ΔGl þ ΔGfc−ΔGbc ð1Þ.

Limestone Gray Marl

Inversion results

Conclusions