نتایج جستجو برای: eocene alkaline rocks
تعداد نتایج: 68026 فیلتر نتایج به سال:
The Ok Tedi Complex hosts a world-class porphyry copper-gold deposit. Samples from the Ok Tedi Complex and the neighbouring Mount Ian Complex were analyzed for major and trace elements using XRF and HR-ICP-MS, and the isotopic composition of S in sulphides was analyzed by Elemental Analyzer. Major element geochemistry indicates that both complexes are alkaline and contain rocks ranging in compo...
Over summer 2017, I continued my research on dikes emplaced during the waning stages of the Neoproterozoic-Ordovician Ross Orogen, a continental arc along the present day location of the Transantarctic Mountains in Antarctica. The dikes intrude calc-alkaline plutons constituting the main intrusive phase as well as metasedimentary rocks formed during early stages of orogenesis. These dikes compr...
85 The physiography of the area is dominated by glaciated landforms carved in gneiss of the Fiordland Complex. The gneiss is generally dioritic, with gradations to quartzo-feldspathic and amphibolitic varieties, and is cut by mainly barren pegmatite veins; epidote is abundant. The rocks commonly show signs of post-consolidational shearing and crushing. There is a well defined zone of strongly c...
kuh- e -zar gold deposit located 35 km west of torbat-e-heydaryeh, (khorassan e- razavi province), east of iran. this deposit is a specularite-rich iron oxide type (iocg). this mine is situated within khaf-bardascan volcanic plutonic belt. based on recent exploration along this belt, several iocg type system plus kuh-e-zar deposit are discovered. in the study area, several type of tuff and lava...
exact petrography and mineral chemistry investigations of pristine and altered rocks of the post-eocene panj-kuh pluton show thatsubsequent to emplacement and crystallization, rocks were subjected to two secondary composition equivalents, sodic-calcic andpotassic alterations, respectively. fresh rocks have syenitic composition and contain plagioclase (labradorite), k-feldspar, magmaticdiopside,...
introduction the area reviewed and studied in this paper is located 5 km southeast of sarbisheh city at eastern border of the lut block (jung et al., 1983; karimpour et al., 2011; richards et al., 2012) in eastern iran between 59° 47′ and 59° 53′ e longitude and 32°30′ and 32°34′ n latitude. the magmatic activity in the lut block began in middle jurassic (165-162 ma) and reached its peak in ter...
Jones and Ewing (1) have presented seismic profiler data from the Bay of Biscay which allows a 120 anticlockwise rotation of the Iberian peninsula between Eocene and Middle to Upper Miocene times. They refer several times to the fact that this va'ue is appreciably less than a rotation of 220, which they believe resulted from our paleomagnetic study of the Lisbon Volcanics (2). We must point out...
Xiphiorhynchus kimblalocki, a new species of extinct billfish from the Eocene of Mississippi, is described. This is the first record of Xiphiorhynchus outside of western Europe, and the material consists of a well-preserved rostrum, three partial vertebrae and two fin spine fragments. Xiphiorhynchus kimblalocki is compared with other living and extinct billfish and appears to be intermediate in...
The Neoproterozoic Nagarparkar Complex is characterized by isolated semicircular hillocks of outcrops of “withinplate” A-type peralkaline to peraluminous granites. Geochemically the granites/rhyolites of the Nagarparkar Complex are characterized by high SiO2, Na2O+K2O, K2O, Fe/Mg, Al2O3, Zr, Nb and Y and low CaO and Sr. Majority of samples show moderate iron enrichment. The rocks show the chara...
The debate about whether Eocene magmatism is considered to be post-collisional or subduction-related not still continues. Here we offer new 40 Ar- 39 Ar ad U-Pb zircon geochronology, mineral chemistry, bulk rock and Sr-Nd-Pb isotope geochemistry data obtained from the southern dike (SD) suite, in comparison with northern (ND) Eastern Pontides. geochronological indicate that SD suite erupted bet...
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