--> Clay Mineral Distribution and Grain Coating Pattern in Ravenglass Estuary Sediments, Daneshvar, Ehsan; Worden, Richard H., #90100 (2009)

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Clay Mineral Distribution and Grain Coating Pattern in Ravenglass Estuary Sediments

Daneshvar, Ehsan1
 Worden, Richard H.1

1Earth & Ocean Sciences, University of Liverpool, Liverpool, United Kingdom.

Clay minerals can significantly control the quality of reservoirs. The occurrence, amount and type of clay minerals can alter the porosity and permeability of a reservoir so that they directly control their economic feasibility. It is thus important to understand the mechanisms which control their formation and distribution. The effect of clay minerals on reservoir properties are not universal and local conditions will govern the effect of a clay mineral on reservoir quality. Estuaries are highly efficient sediment traps and their deposits have high preservation potential, thus, estuarine systems should be widely representative in the geological records. Estuarine sedimentary processes and sedimentology in Ravenglass has been discussed and investigated in order to obtain a clay mineral distribution. The Ravenglass estuary in west coast of Cumbria in north-west England is a local name for an area which encompasses the tidal reaches of the three rivers: Esk, Irt and Mite. Clay minerals distribution and sediments in the estuaries have been studied to identify the sources and the diagenetic processes. Nearly 100 Samples were taken from 15 cores in the all three estuaries in longitude and latitude directions using a combination of Russian corer and Petrol hammer instruments. Based on the X-ray diffraction (XRD), scanning electron microscope and fourier transform infrared spectroscopy (FT-IR) techniques, trends in clay mineral composition were observed. XRD and FT-IR results show kaolinite, illite-smectite and Fe-rich clays are dominant clay minerals in the estuary while in Irt estuary Fe-rich clay minerals are observed to be much less than Esk estuary.SEM images show the new illite-smectite in Irt estuary and new Fe-rich clay minerals in Esk estuary are originated from early diagenesis. At the same time, analysis of clays which have been derived by the river show less quantity of diagenesis for new clay minerals in Esk estuary compared to Irt estuary.Clay mineral distribution pattern in surface and depth in the estuary is not controlled only by the geology formation on the upstream and hydrodynamic processes; diagenetic processes might also have a significant role in it. Furthermore, this investigation shows grain size of sediment considerably may control the quantity of clay mineral grain coating in association with chemical conditions of waters and hydrodynamic factors.

AAPG Search and Discover Article #90100©2009 AAPG International Conference and Exhibition 15-18 November 2009, Rio de Janeiro, Brazil