ABSTRACT:Glauconite is a greenish ferric-iron silicate mineral with micaceous structure, characteristically formed in shallow marine environments. Glauconite has been used as a pigmentation agent for oil paint, contaminants remover in environmental studies and a source of potassium in plant fertilizers, and other industries. Koppeh-dagh basin is extended in Iran, Afghanistan and Turkmenistan countries and Glauconite units exist in this basin. In this research for enhancing and mapping glauconitic units in Koppeh-dagh structural zone in north east of Iran, remote sensing techniques such as Spectral Angle Mapper classification (SAM), band ratio and band composition methods on SPOT, ASTER and Landsat data in 3 steps were applied. * Corresponding author. R.Ahmadirouhani, Email: r_ahmadirohany@yahoo.com
IntroductionGlauconite is a greenish ferric-iron silicate mineral with micaceous structure, The chemical formula of this mineral is:[(K,Na)(Fe3+,Al,Mg)2(Si, Al)4O10(ΟH)2], Glauconite characteristically is formed on submarine elevations ranging in depth from 30 to 1,000 metres below sea level. Glauconite is abundant only in sea-floor areas that are isolated from large supplies of land-derived sediment. It forms by three principal processes: alteration of the fecal pellets of bottom-dwelling organisms; modification of particles of illitic and biotitic clays by seawater; and direct precipitation from seawater. Particles of Glauconite are generally sand-sized or finer (Encyclopaedia Britannica, 2008). Because of its potash and phosphate content, greensand was mined and marketed as a natural fertilizer and soil conditioner for more than 100 years . In the early 1900s the Base Exchange properties of Glauconite were recognized for water treatment and the mineral gained acceptance as a water softener (Spoljaric,1994).By filtration through glauconitic greensands can remove contaminants from landfill leachates (Spoljaric,1974). Also this mineral has used as a pigmentation for paint industry and modern poetry. Consider in economic and environmental cleaner importance of this mineral, Investigation of it is important in industrial development. This research was done in 3 steps: 1-select suitable area with Landsat data; 2-detailed studies and SAM analysis with ASTER data and 3-processing multispectral SPOT image with 2.5 meter resolution for separating units with high anomaly of Glauconite. In order to identify Glauconite in Koppeh-dagh range, four study areas include: 1-Abgram, 2-Sanganeh; 3-Hamam ghalee; and 4-Zavin were selected based on geology maps, field sampling and processing Landsat ETM+ images. Because of the same results in the four study area, only the result of Abgarm area will be discussed here.The results of this study should have considerable potential to evaluate the use of multispectral remote sensing for geological purposes (mapping Glauconite) in Koppeh-dagh.
Geological settingThe investigated area is located in North east of Razavi Khorasan province, north east of Iran, in Koppeh-dagh region (FIG.1). The Kopp...
