An integrated strategy for the exploration of palaeofluvial placer deposits

Abstract

Palaeochannels are the ancient river courses and potential locales of alluvial placer deposits. For the present study, the palaeochannels are demarcated from the Landsat ETM+ data. Digital image processing technique was used to enhance the quality of the traced object. Sites were chosen for ground truth validation and sediment sample collection. The collected sediment samples were subjected to conventional sedimentological analysis. Textural parameters were extracted to confirm the depositional environment through the bivariant plot and log-probability curve. The heavy mineral analysis was performed to assess the alluvial placer resource potential. Among the various types of enhancement techniques adopted, Gaussian and hue saturation value (HSV) are found to be the effective enhancement tools. Palaeochannels are identified from their geometry of a narrow, linear body with lateral to sub-lateral tonal arrangement to the present channel and/or palaeochannels. The average heavy mineral concentration in the palaeochannels is up to 10.34%. Thus, the present paper advocates the integration of remote sensing, digital image processing, granulometric and heavy mineral analyses for the effective identification and exploration of palaeofluvial placer deposits in the deltaic and coastal plain environment of any region.