مورد إلكتروني
Quartz-alunite alteration in the western part of the Virginia Range, Washoe and Storey counties, Nevada.
| العنوان: | Quartz-alunite alteration in the western part of the Virginia Range, Washoe and Storey counties, Nevada. |
|---|---|
| تفاصيل مُضافة: | Vikre P.G. |
| نوع الوثيقة: | Electronic Resource |
| مستخلص: | Large areas of the Miocene volcanic rocks were altered to quartz, alunite and clay minerals, while all the significant deposits of precious metals and mercury occur in or adjacent to extensively altered andesites and dacites. Radioisotope analysis dates the quartz-alunite alteration to 16-9 Ma and the vein mineralisation to 14-10 Ma, closely corresponding to eruptive rock ages of 15-10 Ma. Fluid inclusion stable isotope analysis and microthermometry show that the altering fluids were composed of magmatic and mixed magmatic-meteoric water, and that alteration took place at around 265-205 degrees C. Veins in the Comstock Lode district were also deposited by a mixed magmatic-meteoric fluid and subsurface altered intrusions, such as the Mo-bearing diorite in the Washington Hill alteration zone, can be identified by isotopic analysis of water in surface samples. Mixing of fluids at moderate temperatures may have been important in localising ores. Large areas of the Miocene volcanic rocks were altered to quartz, alunite and clay minerals, while all the significant deposits of precious metals and mercury occur in or adjacent to extensively altered andesites and dacites. Radioisotope analysis dates the quartz-alunite alteration to 16-9 Ma and the vein mineralisation to 14-10 Ma, closely corresponding to eruptive rock ages of 15-10 Ma. Fluid inclusion stable isotope analysis and microthermometry show that the altering fluids were composed of magmatic and mixed magmatic-meteoric water, and that alteration took place at around 265-205 degrees C. Veins in the Comstock Lode district were also deposited by a mixed magmatic-meteoric fluid and subsurface altered intrusions, such as the Mo-bearing diorite in the Washington Hill alteration zone, can be identified by isotopic analysis of water in surface samples. Mixing of fluids at moderate temperatures may have been important in localising ores. |
| مصطلحات الفهرس: | ALUNITE, ANDESITES, CLAY MINERALS, COMSTOCK, DACITES, DIORITES, ECONOMIC GEOLOGY, FLUID INCLUSIONS, GEOCHRONOLOGY, GEOTHERMOMETRY, GOLD, GOLD-SILVER, HYDROTHERMAL ALTERATION, HYDROTHERMAL DEPOSITS, INTRUSIONS, ISOTOPE ANALYSIS, MERCURY, MINERAL DEPOSITS, MINERALISING FLUIDS, MIOCENE, NEVADA, ORE GENESIS, PRECIOUS METALS, QUARTZ, RADIOMETRIC DATING, SILVER, USA, VIRGINIA RANGE, VOLCANIC ROCKS, text |
| URL: | |
| الإتاحة: | Open access content. Open access content |
| ملاحظة: | und |
| أرقام أخرى: | UKMMM oai:icon.iom3.org:47736 1309181152 |
| المصدر المساهم: | INSTITUTE OF MATS MINERALS & MINING From OAIster®, provided by the OCLC Cooperative. |
| رقم الأكسشن: | edsoai.on1309181152 |
| قاعدة البيانات: | OAIster |
| الوصف غير متاح. |