Sedimentation in epithermal veins of the Bohemia mining district, Oregon, USA: Interpretations and significance
نویسندگان
چکیده
Open spaces in epithermal veins of the Bohemia mining district, Oregon, USA, filled with sediments during hydrothermal activity. These sediments consist mainly of chalcedony, rock fragments, and vein quartz fragments. In addition, hematite is deposited during stage three of the vein development. Observed sedimentary features include draping laminae, erosion surfaces, slumping, and graded bedding. Such sediments can be used for reconstruction of the original orientation of vein systems, because the sediment laminae are initially deposited horizontally. Vein sediments record variations in fluid flow due to selfsealing, fracturing, and cessation of hydrothermal activity. Investigation of vein sediments therefore provides an additional tool to unravel the geologic history of epithermal systems. The chalcedonic vein sediments record large temperature drops and highly silica supersaturated waters, probably due to fracturing and pressure release. Hematitic vein sediments indicate sulfide deficient hydrothermal fluids.
منابع مشابه
کانی سازی آنتیموان در ارتباط با گرانیتوئیدهای الوند (همدان)
Antimony mineralization occured in Hamedan district (Faghireh) which is related to Alvand Granitoids. The mineralization occurcd as a series of veins. Thickness of veins are variable and reach up to 0.7m. The veins are emplaced along high angle faults. These faults acted as a pathway for migration of are nuids. Veins are composed of stibnite, pyrite, realgar and orpiment with quartz as a g...
متن کاملIntermediate sulfidation epithermal Cu±Au deposit of RashtAbad (North of Zanjan): evidence of mineralization, fluid inclusions and C-O stable isotope
Rasht Abad Cu±Au deposit is a part of the Tarom-Hashtjin metallogenic belt in the western Alborz-Azerbaijan zone. The exposed units in the area include volcanic, sub-volcanic calc-alkaline to shoshonitic rocks with Upper Eocene age and belongs to magmatic arcs setting. The most important alterations related to mineralization include low temperature silicification and sericitic alterations. Mine...
متن کاملکانیسازی اپیترمال آنتیموان در منطقهی ارغش: کانیشناسی، دگرسانی و زمین شیمی
The Argash antimony ore deposit is located at south of Neyshabour and the eastern part of the Sabzevar zone. This deposit occurs within a sequence of Eocene-Oligocene volcanic-intrusion rocks. The mineralization occurs as open space filling, taking place as irregular veins, veinlets and hydrothermal breccias. The mineralogy of the veins is comparatively simple. The primary antimony-bearing mine...
متن کاملGeological setting of iron oxide-apatite deposits in theBafq district, central Iran with an emphasis on mineralogical,petrographic, and geochemical study of the Sechahun deposit
The objective of this research is to determine all processes in the magmatic evolution and related hydrothermal activities that created the volcanic rocks and associated ore-forming systems of the Bafq mining district. Several iron oxide-apatite (IOA) deposits were investigated in this area with a focus on the Sechahun ore deposit. The Bafq mining district is well known for hosting significan...
متن کاملA Geometric View of Similarity Measures in Data Mining
The main objective of data mining is to acquire information from a set of data for prospect applications using a measure. The concerning issue is that one often has to deal with large scale data. Several dimensionality reduction techniques like various feature extraction methods have been developed to resolve the issue. However, the geometric view of the applied measure, as an additional consid...
متن کامل