Structural Investigations of Afghanistan Deduced from Remote Sensing and Potential Field Data

Hakim Saibi,Saad Mogren,Masood Azizi

doi:10.1515/acgeo-2016-0046

Hakim Saibi, Saad Mogren + Show 1 more

Open Access

https://doi.org/10.1515/acgeo-2016-0046

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Abstract

This study integrates potential gravity and magnetic field data with remotely sensed images and geological data in an effort to understand the subsurface major geological structures in Afghanistan. Integrated analysis of Landsat SRTM data was applied for extraction of geological lineaments. The potential field data were analyzed using gradient interpretation techniques, such as analytic signal (AS), tilt derivative (TDR), horizontal gradient of the tilt derivative (HG-TDR), Euler Deconvolution (ED) and power spectrum methods, and results were correlated with known geological structures. The analysis of remote sensing data and potential field data reveals the regional geological structural characteristics of Afghanistan. The power spectrum analysis of magnetic and gravity data suggests shallow basement rocks at around 1 to 1.5 km depth. The results of TDR of potential field data are in agreement with the location of the major regional fault structures and also the location of the basins and swells, except in the Helmand region (SW Afghanistan) where many high potential field anomalies are observed and attributed to batholiths and near-surface volcanic rocks intrusions. A high-resolution airborne geophysical survey in the data sparse region of eastern Afghanistan is recommended in order to have a complete image of the potential field anomalies.

Highlights

Regional interpretation and analysis of potential field data has been shown to be extremely effective tool to map geology in remote and inaccessible regions and areas buried by shallow cover (Betts et al 2003, McLean et al 2009, Aitken and Betts 2009)
The data shows the extent of basement terranes beneath younger sedimentary basins, the significance of the magnetic responses are more cryptic because anomalies are characterised by longer wavelengths and lower amplitudes because the distance to the magnetic source is greater
Interpretation of magnetic and gravity data reveal an excellent correlation with structural architecture that has previously been related to the collision between the Indian and Eurasian plates, and provides a tool to assess the extent of deformation associated with this continental collision event

Summary

Introduction

Regional interpretation and analysis of potential field data (gravity and aeromagnetic data) has been shown to be extremely effective tool to map geology in remote and inaccessible regions and areas buried by shallow cover (Betts et al 2003, McLean et al 2009, Aitken and Betts 2009). The technique is effective for studies of the architecture character of the Earth’s crust because the data is effective for interpreting 3D geometry of structure and geological bodies (Aitken and Betts 2009, Blaikie et al 2014, Spampinato et al 2015), overprinting relationships (Betts et al 2003), and fault kinematics (Betts et al 2007). Afghanistan preserves some of the most complex and diverse geology in the world associated with the closure of Tethys and the peripherial responses to collision between India and Eurasia. The country is divided into many tectonic blocks bordered by deep-faults that formed or reactivated in response to this collision. These rocks are abundantly rich in natural resources (mineral, petroleum, and natural gas) but much of the Afghanistan’s potential remains unknown. Afghanistan may represent one of the last bastions of untapped mineral and energy resources on the planet

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