Application of remote sensing methods for discrimination of surficial sand types in Qatar oeninsula, the Arabian Gulf

Abstract

The main objective of this work was to investigate the effectiveness of digital processing of Landsat-5 TM data in producing high-quality images for mapping various surficial sand types based on their spectral signatures. To achieve this objective, Landsat-5 TM imagery data were acquired from two dates, one in February 1987 and the other in June 1990. These data were processed on a SUN 4/260 workstation using ERDAS 7.5 software. The applied image processing techniques include preprocessing for radiometric and geometric correction, various enhancement methods, classification and accuracy assessment. A Geographic Information System (GIS) was used to compile data captured and reduced from Landsat TM imagery analysis, together with data from other sources. Spectral measurement of selected surficial sand types was carried out in four different areas of Qatar. These are the western area, the northern tip, the northeastern coast and the southeastern coast. One hundred and forty measurements of spectral reflectances were recorded in the field for various sediment exposures representing the main sand types in the four study areas. From these sand types 53 representative samples were collected for laboratory investigations. These samples were subjected to grain size analyses, X-ray diffraction and laboratory measurement of spectral reflectances. Successful, accurate and detailed geological mapping of these Quaternary sands was achieved by use of a set of diverse false-color composite (FCC) images and by principal component (PC) analysis and image classification. The use of a three-band combination of six non-thermal TM bands indicates that the combination of a visible band (1 or 3), near and mid-infrared bands provides the best discrimination of sand classes. The outcrop of ancient rock types is also revealed. Thus, the results of the remote sensing studies are interpreted in the light of the geologic and tectonic setting of Qatar Peninsula. The work revealed that the surficial aeolian sands can be categorized into three main types, namely-(i) sabkha-derived, salt-rich quartz sands, (ii) beach-derived, calcareous sand and (iii) quartz-rich dune sands. Each of these types has a specific spectral signature affected by the mineralogical composition, grain size, erosional maturity and the mode of occurrence. Such results could be useful to discriminate other surficial deposits in similar environmental conditions prevailing in and lands.

More information

Identifiers

Catalogue record

Export record

ASCII CitationAtomBibTeXData Cite XMLDublin CoreDublin CoreEP3 XMLEndNoteHTML CitationHTML CitationHTML ListJSONMETSMODSMPEG-21 DIDLOpenURL ContextObjectOpenURL ContextObject in SpanRDF+N-TriplesRDF+N3RDF+XMLRIOXX2 XMLReferReference ManagerSimple Metadata