نتایج جستجو برای: cretaceous rocks

تعداد نتایج: 30195  

Journal: :iranian journal of earth science 0
fatemeh hadavi professor, department of geology, ferdowsi university of mashhad, mashhad, iran marziyeh notghi moghaddam assistant professor, department of geology, payame noor university, tehran, iran lida khodadadi department of geology, payame noor university, tehran, iran

calcareous nannofossil assemblages recovered from a long, continuous section have been described from the sarayan region in lut block in east iran. the marine upper cretaceous sediments of this section yield medium diverse and well-preserved calcareous nannofossil assemblages. a structural analysis of upper cretaceous calcareous nannofloras has revealed 30 nannofossil species. a revised zonatio...

The Sungun  copper  porphyry deposit is hosted by a Tertiary magmatic complex in  the  Azarbayjan province , northwestern Iran. The  Sungan mine  in its southern and eastern parts is limited  by early Miocene volcanic and by Late Cretaceous limestone rocks in northern and eastern parts respectively . The Sungun  deposit is associated with a suite of porphyritic granitoids and late dikes intrudi...

بازرگانی گیلانی, کمال الدین, ربیعی, مرتضی, مهرابی, بهزاد,

The Mississippi Valley Type Pb-Zn ore deposits of northern Semnan could be classified as 1) Eram Series in north-west of Shahmirzad and 2) Shahmirzad Series in south and east of Shahmirzad. The host rocks of these mineralizations are Cretaceous carbonates and fawlts have a major role in controlling hypogene ore formation. Age, mineralogy and structural evidences of both series show a resemblanc...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2015
Frieder Klein Susan E Humphris Weifu Guo Florence Schubotz Esther M Schwarzenbach William D Orsi

Subseafloor mixing of reduced hydrothermal fluids with seawater is believed to provide the energy and substrates needed to support deep chemolithoautotrophic life in the hydrated oceanic mantle (i.e., serpentinite). However, geosphere-biosphere interactions in serpentinite-hosted subseafloor mixing zones remain poorly constrained. Here we examine fossil microbial communities and fluid mixing pr...

Journal: :iranian journal of earth science 0
farhad moharami department of geology, payame noor university issa azadi faculty of earth science, shahid beheshti university, tehran, iran mirsaleh mirmohamadi school of mining engineering, faculty of engineering, university of tehran, iran javad mehdipour ghazi faculty of earth science, shahid beheshti university, tehran, iran mohammad rahgoshay faculty of earth science, shahid beheshti university, tehran, iran

chaldoran area in nw of iran has mesozoic oceanic crust basement. the studied rocks of this region can be divided into three groups: ophiolitic gabbros and pillow lavas, ophiolitic volcanoclastics and eocene lava flows. ophiolitic mafic rocks show continental volcanic arc natures and eocene lava flow shows oib-like nature. during the mesozoic,the chaldoran region was situated in the active cont...

Journal: :International Geology Review 2023

The classic Neotethyan Ankara Melange formed within the Triassic-Eocene İzmir-Ankara-Erzincan ocean (‘N Neotethys’), bordered in central Anatolia by Kırşehir and Tauride-Anatolide continental units to south discontinuous Sakarya continent northwest. Farther north, separate Intra-Pontide probably remained partly open until early Cenozoic. developed via phases of intra-oceanic accretion (mainly p...

2013
Mariela S. Fernández Rodolfo A. García Lucas Fiorelli Alejandro Scolaro Rodrigo B. Salvador Carlos N. Cotaro Gary W. Kaiser Gareth J. Dyke

We report the first evidence for a nesting colony of mesozoic birds on Gondwana: a fossil accumulation in Late Cretaceous rocks mapped and collected from within the campus of the National University of Comahue, Neuquén City, Patagonia (Argentina). Here, Cretaceous ornithothoracine birds, almost certainly Enanthiornithes, nested in an arid, shallow basinal environment among sand dunes close to a...

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