کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
8913721 | 1640172 | 2017 | 138 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Anatomy of a mountain: The Thebes Limestone Formation (Lower Eocene) at Gebel Gurnah, Luxor, Nile Valley, Upper Egypt
ترجمه فارسی عنوان
آناتومی کوه: سازنده سنگ آهک تیبز (ائوسن پایین) در گبل گورنا، اقصر، دره نیل، مصر بالا
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کلمات کلیدی
سنگ آهک تیب، پایین ائوسن، گبل گورنه، مصر، چینهشناسی دنباله،
موضوعات مرتبط
مهندسی و علوم پایه
علوم زمین و سیارات
زمین شناسی
چکیده انگلیسی
We present a detailed geologic study of the Thebes Formation at Gebel Gurnah in its locus typicus on the West Bank (opposite Luxor) of the Nile River in the Upper Nile Valley, Egypt. This is the first detailed measurement and lithologic description of the â¼340 m thick (predominantly) carbonate section. The Thebes Formation is divided into thirteen major lithic units (A to M). We interpret data on the lithologic succession and variations, whole rock/clay mineralogy, and macro/micropaleontology in terms of deposition on a shallow carbonate platform episodically influenced by continental runoff, and describe six depositional sequences that we place in the global framework of Lower Eocene (Ypresian) sequence stratigraphy. We note however significant incompatibilities between the Thebes depositional sequences and the global sequences. We emend the definition of the Thebes Formation by defining its top as corresponding to level 326 m at the top of Nodular Limestone 'L' (NLL), and assigning the overlying beds to the Minia Limestone Formation. New biostratigraphic data and revision of previous studies establish the direct assignment of the Thebes Formation to planktonic foraminiferal Zones E4/P6b (upper part), E5/P7 and (indirectly) Zone E6/P8, and (probably, indirectly) Zone E7a/”P9”, and to calcareous nannofossil Zone NP12 and lower Zone NP13 of the Lower Eocene (Ypresian) and provide a temporal framework spanning â¼Â 2.8 Myr from <52.45 to â¼49.6 Ma for the deposition of the Thebes Formation prior to the prominent sea level fall (â¼49.6 Ma) towards the end of the Early Eocene. Dominantly carbonate deposition, with a strongly reduced detrital influx, occurred on a very wide shelf (probably) at least â¼Â 100 km from the coastline. The thick sedimentary succession and the marked vertical lithologic variations are interpreted as resulting from sea level fluctuations imprinted on a long-term decrease in sea-level associated with rapid subsidence reflecting tectonic relaxation after the major Late Paleocene tectonic reorganization of the Syrian Arc.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of African Earth Sciences - Volume 136, December 2017, Pages 61-108
Journal: Journal of African Earth Sciences - Volume 136, December 2017, Pages 61-108
نویسندگان
Christopher King, Christian Dupuis, Marie-Pierre Aubry, William A. Berggren, Robert O.'B. Knox, Wael Fathi Galal, Jean-Marc Baele,