نوع مقاله : مقاله پژوهشی
نویسندگان
1 گروه زمین شناسی، دانشکده علوم، دانشگاه هرمزگان، بندر عباس، ایران
2 دانشگاه تحصیلات تکمیلی علوم پایه زنجان
3 مدیریت اکتشاف شرکت ملی نفت ایران
4 مدیریت اکتشاف شرکت ملی نفت، تهران، ایران
5 گروه زمین شناسی، پژوهشگاه صنعت نفت، تهران، ایران
چکیده
کلیدواژه‌ها
موضوعات
عنوان مقاله [English]
نویسندگان [English]
Facies analysis of the Sargelu Formation, exposed in the Lurestan zone, indicate an outer ramp to basinal depositional environment with pelagic/hemipelagic sedimentation punctuated by depositions from turbidites. Field and laboratory analysis of the facies succession display two factors played a major role: oxygenation and sea-floor current intensity. Results indicate that the sediments were deposited in an anoxic to dysoxic, relatively deep, sea-floor environment as revealed by the presence of: a) organic-rich shales and limestones and b) absence of benthic fauna and burrowing. In contrast, Posidonia pelagic bivalves are interpreted as the result of the proliferation of this bivalve during periods of favorable environmental conditions on the sea floor. Thin to medium beds of graded wackestone/packstone to rudstone/floatstone and accumulations of thin shells of Posidonia pelagic bivalves indicate sporadic reworking of the sea floor by turbidity currents. Disarticulation, fragmentation, and reorientation of Posidonia pelagic bivalves can be indicative of reworking, by turbidity currents which periodically interrupted periods of lower-energy suspension sedimentation. This study shows that the proliferation of pelagic bivalves in outer ramp to basinal depositional environments of carbonate platform of the Sargelu Formation could be related to run-off from the continent, which provided nutrients.
کلیدواژه‌ها [English]
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