نتایج جستجو برای: the lower triassic rocks indicate

تعداد نتایج: 16087334  

Journal: :Quarterly Journal of the Geological Society 1876

2018
Wei Lin Michel Faure Patrick Monié Urs Schärer Liangsheng Zhang Yan Sun

In south China the Lushan massif forms a Jurassic through Early Triassic [e.g., Mattauer et al., 1985, topographic high of the South China Block south of the 1991; Okay et al., 1993; Hacker et al., 1996; Gilder et al., Qinling-Dabie belt. The Lushan massif consists of two main 1999]. The noah directed continental subduction of south lithotectonic units separated by a major tectonic ontact: a Ch...

2005
R. Klemd M. Bröcker B. R. Hacker J. Gao P. Gans K. Wemmer

The western Tianshan high-pressure/low-temperature orogenic belt in NW China contains eclogite-facies metavolcanic rocks and omphacite-bearing blueschists. Previous Sm-Nd (omphacite, garnet, glaucophane, whole rock) and Ar/Ar (crossite) dating of eclogite-facies rocks has suggested an age of ca. 345 Ma as the best approximation for the timing of peak metamorphic conditions. The samples describe...

Mahboubi, Asadoalllah, Moussavi-Harami, Seyed reza, Zamani, Fatemeh, Zand-Moghadam, Hamed,

The hosted-rocks of the Pb-Zn ore deposits in two mines of Karavangah and Dehno (north of Kuhbanan) contain carbonate rocks of the Shotori Formation (Middle Triassic).The identified carbonate facies consists of limestone and dolomite, but ore bodies mainly occurred in dolomite facies. Petrographic studies show that the dolomites can be divided into four classes including fine crystalline, mediu...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه اصفهان - دانشکده علوم 1389

this research concentrates on the lithostratigraphy, biostratigraphy, microfacies and sedimentary environment of the asmari and gachsaran formations at southwest firuzabad. the thickness of the studied section in all 608.95 meters that 220.8 meters belong to the asmari formation and 387.95 meters belong to the gachsaran formation (champe and mol members). in the study area, the asmari formation...

Journal: :Geochemistry Geophysics Geosystems 2022

Abstract Calcium isotopes (δ 44/40 Ca) are particularly useful in palaeo‐environmental studies due to the key role of carbonate minerals continental weathering and their formation seawater. The calcium isotope ratio can provide hints on past changes fluxes, environmental shifts, ecological factors alternatively diagenesis rocks. investigation Late Triassic record offers a great opportunity eval...

2007
SARA B. PRUSS JONATHAN L. PAYNE DAVID J. BOTTJER

Outcrops of the Lower Triassic (Spathian) Virgin Limestone Member (Moenkopi Formation) in the southwestern United States contain the oldest known metazoan bioherms formed in the aftermath of the endPermian mass extinction. These small buildups, up to 1.0 m in diameter and 0.2 m high, were constructed by cementing bivalves. The bivalve bioherms accreted in a shallow, subtidal environment above s...

Journal: :journal of sciences islamic republic of iran 0
n. naimi ghassabiyan

the study area is situated in the middle part of the tabas block. it contains outcrops of rocks that formed along longitudinal faults in early cimmerian orogenic phase. the basin subsided along these faults from the late triassic to early cretaceous, which include two sedimentary cycles. a sedimentary cycle, related to upper triassic to bajocian is known as shemshak group. another sedimentary c...

Journal: :زمین شناسی اقتصادی 0
رضا زارعی سهامیه سارا ابراهیمی

introduction the study area is a small part of the urumieh-dokhtar structural zone in the markazi province, located in the northeastern part of the farmahin, north of arak (hajian, 1970). the volcanic rocks studied from the area include andesite, dacite, rhyodacite, ignimbrite and tuff of middle to late eocene age (middle lutetian to upper lutetian) (ameri et al., 2009). it seems that folding a...

Journal: :Comptes Rendus Geoscience 2021

Located at the westernmost tip of Mediterranean, Gibraltar Arc is a segment Alpine belt that exhibits peridotite massifs associated with high-grade crustal metamorphic units. The timing and mechanisms exhumation these crust–mantle associations are still debated in Rif Morocco as well Betic Cordilleras Spain. A structural, petrographic, geochronological study ( 40 Ar– 39 Ar method) performed Ben...

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