نتایج جستجو برای: host rock

تعداد نتایج: 251262  

Journal: :زمین شناسی اقتصادی 0
رضا شمسی پور دهکردی مریم صادقی زهره غلامی فشارکی

nain ophiolite melange is located 140 km east of isfahan. based on the geological studies, this area belongs to mesozoic ophiolite of urumieh – dokhtar zone, west of central iran. country rocks are pridotite and serpentinized pridotite. the pridotite rocks are composed of harzburgite, lherzolite and replacement dunite which is belong to spinel pridotite facies.paragenesis of ore minerals are ch...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2015
Katherine L French Christian Hallmann Janet M Hope Petra L Schoon J Alex Zumberge Yosuke Hoshino Carl A Peters Simon C George Gordon D Love Jochen J Brocks Roger Buick Roger E Summons

Hopanes and steranes found in Archean rocks have been presented as key evidence supporting the early rise of oxygenic photosynthesis and eukaryotes, but the syngeneity of these hydrocarbon biomarkers is controversial. To resolve this debate, we performed a multilaboratory study of new cores from the Pilbara Craton, Australia, that were drilled and sampled using unprecedented hydrocarbon-clean p...

2015
Elke T. Vermeulen Deborah L. Ashworth Mark D.B. Eldridge Michelle L. Power

Host-parasite relationships are likely to be impacted by conservation management practices, potentially increasing the susceptibility of wildlife to emerging disease. Cryptosporidium, a parasitic protozoan genus comprising host-adapted and host-specific species, was used as an indicator of parasite movement between populations of a threatened marsupial, the brush-tailed rock-wallaby (Petrogale ...

2008
Sarah J. Fowler Frank J. Spera

[1] A mechanism for explosive volcanic eruptions based on multicomponent phase equilibria modelling of four explosive volcanic systems is proposed. In each system, either isochoric or isobaric crystallization, where either crystals or crystals and exsolved fluid are chemically fractionated from melt, leads inevitably to near-solidus dynamical instability culminating in violent explosive eruptio...

Karimpour, , Malekzadeh Shafaroudi, , Miri, ,

Bijvard prospect area is located in the northern part of Central Iran zone, Sabzevar zone, about 40 km north of Bardaskan. The rock units exposed in the area include Cretaceous volcano-sedimentary rocks (andesite, basalt, graywacke and conglomerate) that syenogranite porphyry unit has intruded into them.  Mineralization has structural control, with N35E trending, and has altered the andesitic r...

2016
Nathan R. Daczko Sandra Piazolo Uvana Meek Catherine A. Stuart Victoria Elliott

Geochemical signatures throughout the layered Earth require significant mass transfer through the lower crust, yet geological pathways are under-recognized. Elongate bodies of basic to ultrabasic rocks are ubiquitous in exposures of the lower crust. Ultrabasic hornblendite bodies hosted within granulite facies gabbroic gneiss of the Pembroke Valley, Fiordland, New Zealand, are typical occurrenc...

2002
Keith P. Harrison Robert E. Grimm

[1] Models of hydrothermal groundwater circulation can quantify limits to the role of hydrothermal activity in Martian crustal processes. We present here the results of numerical simulations of convection in a porous medium due to the presence of a hot intruded magma chamber. The parameter space includes magma chamber depth, volume, aspect ratio, and host rock permeability and porosity. A prima...

Journal: :The Journal of parasitology 2003
Megan R Collins J Janovy

This study addressed the problem of local patterns of host specificity among Ancyrocephalinae (Monogenoidea) on bass and sunfish species, when the hosts occur in different species combinations in separate ponds. One hundred fifty-three fish of the Centrarchidae, from 4 study sites in Nebraska, were collected. Host species included bluegill (Lepomis macrochirus), green sunfish (L. cyanellus), la...

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