MicrofaciesAnalysis and Paleoenvironment of Carbonate Sedimentary Rocks(Asmari Formation)in Posht-Darband, Hamedan
Message:
Abstract:
Carbonate sedimentary rocks equivalent to Asmari Formation containing thick and thin bedded and massive limestones with a thickness of 160m studied in Posht-Darband، Hamadan. The base of the sedimentary sequence begun with a transgressive conglomeratic horizon. This horizon is composed of rock fragments such as cherts، schists and fossiliferouslimestones which are derived from adjacent old rock units. The lower contact of conglomerate horizon overlains the metamorphic rocks and the upper contact is covered by alluvium. Based on the study of thin sections from Asmari Formation، two main facies belts containing inner and middle ramps are recognized. The inner ramp composes restricted lagoon، rotalid shoal، protected lagoon and patch reef whiles the middle ramp contains proximal، middle and distal parts respectively. Based on microscopic studies، eight microfacies are presented which are consist of; 1-Large perforate foraminifera-bioclastwackestone، 2-Perforate foraminifera-red algal-bioclastpackstone/grainstone، 3-Coralgal-bioclast packstone/grainstone، 4-Coral-redalgal packstone/grainstone، 5-Imperforate foraminifera-pelloid-bioclastpackstone، 6-Rotalia grainstone، 7-Perforate-imperforate foraminifera packstone/grainstone and 8-Miliolid-bioclast-intraclast packstone. They are deposited in seven sedimentary environments. According to microfacies، this formation is distributed from tidal flat to middle ramp. The Chatian (Late Oligocene) age is attributed to these carbonate rocks based on benthic foraminifera recorded.
Language:
Persian
Published:
Geosciences Scientific Quarterly Journal, Volume:25 Issue:97, 2016
Page:
123
magiran.com/p1477411  
روش‌های دسترسی به متن این مطلب
اشتراک شخصی
در سایت عضو شوید و هزینه اشتراک یک‌ساله سایت به مبلغ 300,000ريال را پرداخت کنید. همزمان با برقراری دوره اشتراک بسته دانلود 100 مطلب نیز برای شما فعال خواهد شد!
اشتراک سازمانی
به کتابخانه دانشگاه یا محل کار خود پیشنهاد کنید تا اشتراک سازمانی این پایگاه را برای دسترسی همه کاربران به متن مطالب خریداری نمایند!