Dedolomitization of dolocrete deposits in Kuwait,Arabian Gulf |
| |
| Authors: | F I Khalaf M S Abdal |
| |
| Institution: | (1) Kuwait Institute for Scientific Research, PO Box 24885, 13109 Safat, Kuwait;(2) Present address: Suez Canal University, 5, St. 27, Port-Fouad, Port-Said, Egypt |
| |
| Abstract: | Dedolomitization of a dolocrete profile hosted in Mio-Pleistocene siliciclastic deposits in the area of Kuwait City, Arabian Gulf was investigated. Dolocrete dolomite crystals vary considerably in size, shape and internal structure; however, they are mostly zoned. Zonation is usually due to the alteration of cloudy and clear zones. The cloudy zones, which are mostly formed of disordered metastable dolomite, are more susceptible to dedolomitization than the stable, well ordered clear zones. Two modes of dedolomitization were recognized; the first involves complete dissolution of the metastable dolomite followed by precipitation of intracrystalline cavity-filling calcite. The second is a pseudomorphic replacement of dolomite by calcite. This replacement takes place by the simultaneous dissolution of dolomite and precipitation of calcite in such a manner that the original dolomite fabrics are inherited in the dedolomite. Exposed and near-surface dolocrete profile (less than 5 m deep) are almost completely dedolomitized and altered to secondary calcrete whereas subsurface profiles are slightly dedolomitized. Dedolomitization of the sub surface dolocrete profiles may indicate the effect of flushing by fresh groundwater; which flows from west to east, whereas the alteration of the exposed dolocrete profile could be attributed to be an effect of meteoric water. A new mode of calcrete genesis by dedolomitization and/or complete calcitization of precursor dolocrete is suggested. |
| |
| Keywords: | Dolcretes Dedolomitization Arabian Gulf |
| 本文献已被 SpringerLink 等数据库收录！ |
|
