Utilizing landsat-8 sensor operational land image data for hydrothermal alteration mapping within Anka Schist Belt, northwestern Nigeria

Ohinowi Aliyu,Kankara Aliyu

doi:10.5937/zbdght2002127a

Abstract

Exploring for mineral deposits within the Anka Schist Belt involves the use of traditional geological techniques such as geochemical and geophysical studies that are very expensive and time consuming. There is therefore need for a better alternative that will provide accurate and reliable information with cost effective and time efficient solution. This effort seeks to explore the potential of remotely sensed digital data in highlighting mineralized zones through hydrothermal alteration studies. Landsat 8 OLI data covering the investigated area was used to detect and map locations of hydrothermal alterations. Image processing methods used were spectral enhancement, false colour composites, band rationing and Principal Component Analysis. Results of false colour composites of band 5: 7: 3 highlighted generally locations of hydrothermal alterations. Band ratios of 4/2, 6/7 and 6/5 revealed the presence of ferric iron minerals, clay rich minerals and ferrous minerals respectively. Principal Components (PCs) of two sets of images (2, 4, 5, 7 H-image and 2,5,6,7 F-image) depicting iron-oxide and hydroxyl mineral deposits as bright pixels were generated. Colour composite of H, F and H+F images enhanced the location of the mineral deposits, by showing areas of mineralization in dark blue (Fe rich), bright yellow (clay rich) and white (Fe and clay rich areas) pixels. Field coordinates of mining locations were superimposed on the remote sensing generated mineral map. The results were found to be in tune. This study recommends the use of remote sensing and geospatial technology in mineral studies through hydrothermal alteration within the basement complex rocks of Nigeria.

Highlights

A swift look at the history of establishment of Remote Sensing Technology in Nigeria shows that its development in the nation began in 1972, when the University of Ife ( Obafemi Awolowo University) developed a proposal to the Federal Government of Nigeria with the aim of acquiring data in USA’s Earth’s observation satellite– LANDSAT-2
The data was acquired, while some positives and negatives were at OAU and at the Regional Remote Sensing facility, Nairobi, Kenya
The FGN included it in her 1975-1980 third National Development Plan, a budgeted sum of N10, 000, 000 for the establishment of a National Remote Sensing Center

Summary

Introduction

A swift look at the history of establishment of Remote Sensing Technology in Nigeria shows that its development in the nation began in 1972, when the University of Ife ( Obafemi Awolowo University) developed a proposal to the Federal Government of Nigeria with the aim of acquiring data in USA’s Earth’s observation satellite– LANDSAT-2. Between 1975 to 1981 some proposals which contained action-oriented recommendations of concrete steps towards a viable National Remote Sensing program in Nigeria were developed. The FGN included it in her 1975-1980 third National Development Plan, a budgeted sum of N10, 000, 000 for the establishment of a National Remote Sensing Center. An overseas mission was undertaken to Canada, USA and Brazil, and after expenditure of N250, 000 the allocation was withdrawn This was followed by inter and intra ministerial conflicts of interests (Sebastian, 2000)

Methods

Results

Conclusion