Sentences with phrase «by hydrothermal fluids»
Marbles in metamorphic aureoles and iron - rich skarns appear to be favored sites for gold mineralization in these deposits, perhaps due to the rheological character, permeability after fracturing, and chemical reactivity of those rocks to alteration by hydrothermal fluids.
http://www.paramountnevada.com/ Not exact matches
Gravest doubts emerged in 2002, when a team led by Oxford's Professor Martin Brasier (co-author of this current study) revealed that the host rock was not part of a simple sedimentary unit but rather came from a complex, high - temperature hydrothermal vein, with evidence for multiple episodes of subsurface fluid flow over a long time.
In the deep gold mines of South Africa, and under the sea, at hydrothermal vents where breaks in the fissure of Earth's surface that release geothermally heated waters — hydrogen - rich fluids host complex microbial communities that are nurtured by the chemicals dissolved in the fluids.
* David Kring explores the hydrothermal system triggered by the impact, including metasomatism (lithologic chemistry altered by hot fluids), and how the system could have incubated new life as it cooled over thousands of years post-impact.