We present the iron isotope composition of primary, diagenetic and metamorphic minerals in five samples from the contact metamorphosed Biwabik Iron Formation. These samples attained peak metamorphic temperatures of <200, <340, ~500, <550, and <740 C respectively. dFe of bulk layers ranges from –0.8 to +0.8&; in some samples the layers may differ by >1& on the millimeter scale. Minerals in the l...

We present the iron isotope composition of primary, diagenetic and metamorphic minerals in five samples from the contact metamorphosed Biwabik Iron Formation. These samples attained peak metamorphic temperatures of <200, <340, ~500, <550, and <740 C respectively. dFe of bulk layers ranges from –0.8 to +0.8&; in some samples the layers may differ by >1& on the millimeter scale. Minerals in the l...

Abst rac t -Large parts of the Central Eastern Desert of Egypt consist of Neoproterozoic nappes of ophiolite and island-arc volcanic rocks. Beneath these nappes metamorphic basement domes are exposed in tectonic w indows such as the Meatiq basement. The mineral and whole rock chemistry of amphibol i tes included in the teconical ly lowermost granitoid gneiss, within the metasedimentary cover of...

Chloride-rich brines are increasingly recognized as playing an important role in high pressure and temperature metamorphic and magmatic systems. The origins of these saline multicomponent fluids are debated, but experimental evidence suggests that regardless of their origin they must be important agents of rock alteration and mass transfer wherever they occur. Studies of the solubility of quart...

The Los Alamos Hot Dry Rock Reservoir is an experimental geothermal project in north-central New Mexico. A fractured zone was created within otherwise impermeable igneous and metamorphic rock by injecting water into a borehole under high pressure, at about 3.5 km depth. During the injection process, the seismic waves created by the fracturing events were recorded by seismometers located in four...