The Mount Thompson 7.5 Minute Quadrangle is located in the central Boulder Batholith, between the cities of Butte and Helena. The Boulder batholith is host to numerous metalliferous vein deposits, including those in the Butte District. Recent USGS (EDMAP)-funded geologic mapping at 1:24,000 scale in the Mount Thompson Quadrangle during...
There are few modern isotopic ages of igneous rocks and polymetallic (Pb-Zn-Ag-Cu-Au) hydrothermal mineral veins of the Mt. Thompson quadrangle in southwestern Montana. Lithology ages of this region vary from approximately 85-80 Ma Butte granite(Kbg) (Lund et al. 2002) to 48.6 Ma of Lowland Creek Volcanic Field (LCVF) (Dudas et...
The Botija Cu-Mo-Au porphyry deposit is located in the Cobre Panamá mining district, which contains several deposits with a global measure and indicated and inferred resource of 14.8 MT of Cu. These deposits are associated with the Cerro Petaquilla batholith, which has U/Pb zircon ages of 26-33 Ma (Whattam et...
:
______________________________________________________________________________
John H. Dilles
The Botija Cu-Mo-Au porphyry deposit is located in the Cobre Panamá mining
The Boulder Batholith and Elkhorn Mountains Volcanics (EMV) formed concurrently during shortening between ~85-76 Ma near the end of Mesozoic Cordillera arc magmatism. Together they represent an exceptionally well-preserved and voluminous record of continental arc magmatism. We report field and analytical results from studies of the EMV and Boulder Batholith...
Typical porphyry-type Cu-Mo mineralization predates and underlies the well-known
Main Stage polymetallic veins of the Butte district, Montana. This thesis presents the
first systematic study of the isotopic characteristics of the pre-Main Stage K-silicate and
sericitic wallrock alteration related to the porphyry Cu-Mo stage.
Oxygen and hydrogen isotopic compositions were...
Magmatic sulfides from Yerington, Nevada, and Yanacocha, Peru, were analyzed by laser ablation-inductively coupled mass spectrometry (LA-ICPMS) and electron microprobe to determine copper, gold, and silver concentrations and ratios in order to examine the relationship to the metal content of related magmatic-hydrothermal ores. The magmatic sulfides occur in plutonic rocks...
The Tobin Range of central Nevada lies in the Basin and Range extensional province near the transition between more extended terrane (>50%) to the south and east, and generally less extended terrane to the north and west. Geologic mapping, 40Ar/39Ar dating and whole-rock geochemical analysis were employed to establish the...
Magmatic-hydrothermal ore deposits are giant geochemical anomalies in the earth’s crust most often generated by normal magmatic terrestrial processes. They are often associated with oxidized and hydrous intermediate to highly evolved magmas that have concentrated metals and have the necessary components to efficiently extract and transport them as ascending magmatic-hydrothermal...
Near-surface advanced argillic hydrothermal alteration zones, also referred to as lithocaps, are characterized by quartz, alunite, clays (pyrophyllite and kaolinite group minerals), and minor F-bearing aluminosilicates (i.e., topaz, zunyite, diaspore, and APS) that form where water-, SO2-, and HF-rich gas condenses into shallow groundwater, acidifies, and reacts with rocks. The...
:
_____________________________________________________________________
John H. Dilles
Near-surface advanced argillic hydrothermal alteration zones, also
Porphyry Cu-(Au-Mo) deposits are critical sources of several economically important metals. The processes governing the total metal endowment and relative proportions of ore metals at these large magmatic-hydrothermal deposits remain uncertain. The Sulphurets porphyry district, in northwestern British Columbia, Canada, contains four porphyry Au-Cu-Mo deposits that each feature distinct Cu/Au...
