K-Ar ages and time span of emplacement of the Boulder Batholith, Montana

Tilling, Robert I.; Klepper, M.R.; Obradovich, John D.

doi:10.2475/ajs.266.8.671

Cited by 63 publications

(16 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Although K-Ar ages indicate emplacement of the batholith at approximately 78 to 68 Ma [Tilling et al, 1968], apparent ages on the alteration assemblages indicate that the mineralization occurred in Paleocene time, at least 5-10 m.y. after emplacement of the late plutons [Meyer et al, 1968] Sheppard and Taylor [1974] obtained oxyge~ and hydrogen isotope data on the Butte ore deposits and showed that meteoric hydrothermal waters were the dominant constituent of the ore-forming fluid during Main Stage mineralization.…”

Section: Paleocene Systemmentioning

confidence: 97%

Tertiary meteoric hydrothermal systems and their relation to ore deposition, northwestern United States and southern British Columbia

Criss¹,

Fleck²,

Taylor³

1991

J. Geophys. Res.

View full text Add to dashboard Cite

Tertiary meteoric hydrothermal systems have altered the rocks exposed over more than S% of the land surface of the northwestern United States and southern British Columbia, including at least 25,000 1m? in Idaho. The systems typically involved convective circulation of fluid derived from ordinary meteoric groundwater& around crystallizing, calc-alksline, epizonal plutons eiiiP.laced into coeval volcanic cover rocks.These individual systems had widely ranging "lifetimes" of 10' to 1Cf >:~and operated ~ocally throu~out the Cenozoic, although the most profound devolopment of such activity occurred dunng Eocene time. Individual systems varied in size from a few tens of S'JUBre kilometers (Y ankec: Fork, I~o) or less ~ ~v~ral thousand square kilometers (Sawtooth and Castro nng zones, Idaho) Typically, reg~onsl propyhtization aacompanied the fluid circulation, although th~ .lJ!ghe~-tempe':B~re ~teration assemblages. were ~evel~ed locally as were intense alteration effects (e.g., silicification, senc1tization, etc.) near some ve1ns and m Jrurung districu. A significant amount, PC?bably 25-SO%, of the mineral production and pote!ltial i~ the region is closely related to Tertiary meteonc hydrothermal systems. Oxygen and hydrogen 1sotop•c data clearly demonstrate the close geologic association of meteoric hydrothermal systems amd mineralization in (1) the Paleocene, Cu-Zn-Pb-Mn Main Stage mineralization at Butte, Montana; (2) numerous Eocene epithermal deposits principally valued for Au and Ag but also including significant deposits of Cu, Pb, Zn, F, Sb, etc., as at Republic, Washington, and in several mining districts in the Idaho batholith and the Challi~ volcanic field; (3) several Eocene skarn deposits valued for W (lma, Idaho) and Cu (Mackay, Idaho); (4) Important leadsilver vein and replacement deposits of Tertiary (Bluebell, British Columbia) and of probable Cre~ceous and early Tertiary age (Wood River, Idaho); (S) several potentially economic Mo-, Be-, and U-beanng Eocene "porphyry" plutons; and (6) Miocene epithermal deposits, most prominently the Au and Ag bearing veins at Silver City and DeLamar, Idaho, the Hg deposits at the McDermitt caldera, Nevada and Oregon, and . INIRODUCI10NOxygen and hydrogen isotopic ratios are the only intrinsic properties of H20 that are known to be both variable and easily measured; hence they provide the only unequivocal data on the origin of natural aqueous fluids [Craig et a/., 1956]. Application of these principles proves that fluids derived from meteoric waters played a critical role in the formation of numerous ore deposits of the western United States. Prominent examples are the epithermal Au and Ag deposits of Nevada, such as Tonopah, Goldfield, and the Comstock Lode [Taylor, 1973[Taylor, , 1974aO'Neil and Silberman, 1974], and several copper porphyry and vein deposits [Sheppard et al., 1969[Sheppard et al., , 1971. A particularly important example is the Main Stage mineralization of the zoned Cu-Zn-Pb-Mn deposit at Butte, Montana [Garlick and Epstein, 1966;Sheppard and Ta...

show abstract

Section: Paleocene Systemmentioning

confidence: 97%

Tertiary meteoric hydrothermal systems and their relation to ore deposition, northwestern United States and southern British Columbia

Criss¹,

Fleck²,

Taylor³

1991

J. Geophys. Res.

View full text Add to dashboard Cite

show abstract

“…The Belt terrane was affected by the East Kootenay Orogeny at <1370 Ma, which created a pulse of bimodal magmatism, basin rifting, and subsidence (Tilling et al, 1968;Doughty and Chamberlain, 1996). This led to regional-scale burial metamorphism and also produced gentle warping and cleavage of Belt Supergroup rocks (McMechan and Price, 1982;Doughty and Chamberlain, 1996).…”

Section: Belt Supergroupmentioning

confidence: 99%

Geochemistry of Magnetite from Hydrothermal Ore Deposits and Host Rocks of the Mesoproterozoic Belt Supergroup, United States

et al. 2012

View full text Add to dashboard Cite

“…100-55 Ma; Armstrong et al, 1977;Lageson et al, 2001), the Boulder batholith and its satellites (81-73 and 64-61 Ma;Tilling et al, 1968;Hamilton and Meyers, 1974;Brumbaugh and Hendrix, 1981;Lund et al, 2002;Wooden et al, 2008), the Pioneer batholith (77-65 Ma; Snee, 1982;Marvin et al, 1983;Arth et al, 1986), and the Tobacco Root batholith (77-71 Ma; Mueller et al, 1996). Extrusion of the Cretaceous Elkhorn Mountains volcanics was coeval with early stages of Boulder batholith intrusion (80-83 Ma; Robinson et al, 1968;Tilling, 1974;Lageson et al, 2001), resulting in a thick volcanic carapace (26,000 km 2 and 4.6 km thick) that blanketed the area (Klepper and Smedes, 1959;Robinson et al, 1968).…”

Section: Geologic Settingmentioning

confidence: 99%

Paleogene postcompressional intermontane basin evolution along the frontal Cordilleran fold-and-thrust belt of southwestern Montana

Schwartz

2013

Geological Society of America Bulletin

View full text Add to dashboard Cite

The Paleogene Renova Formation is the earliest record of postcompressional sedimentation within and adjacent to the Helena Salient of the Cordilleran fold-and-thrust belt in southwestern Montana. Paleocurrent and compositional data from basin-margin facies document radiating paleodispersal away from high-relief (≥2 km) highlands coincident with modern mountainous areas. Source rocks within the paleohighlands included the same Archean metamorphic; Proterozoic, Paleozoic, and Mesozoic sedimentary; and Mesozoic plutonic and volcanic rocks as exposed in modern uplifts. Paleocurrent and compositional data from trunk fl uvial conglomerates and sandstones document the existence of an interbasinal drainage system that connected the Three Forks, western Gallatin, and Townsend Basins with headwaters farther to the west and southwest near the present-day Montana-Idaho border. Overall, the distribution of Paleogene mountainous areas and basins closely resembled modern geography, and the Paleogene drainage network was strikingly similar to the modern Missouri River headwater system. The Renova Formation records the early stages of decay of the Cordilleran orogenic belt, including the evolution of a complex intermontane basin network in southwestern Montana. High-energy Late Cretaceous to early Eocene fl uvial systems carved deep, large-scale paleovalleys into the orogenic wedge along zones of structural and stratigraphic weakness. At least a 5 km thickness of overburden was removed during this time. Incision was temporally correlative with early Cenozoic regional uplift and subtropical climatic conditions. Subsequent deposition of the Renova Formation was temporally correlative with the cessation of uplift, the initiation of crustal extension, and climatic cooling. However, extension is not interpreted to have played a major role in earliest basin development.

show abstract

K-Ar ages and time span of emplacement of the Boulder Batholith, Montana

Cited by 63 publications

References 0 publications

Tertiary meteoric hydrothermal systems and their relation to ore deposition, northwestern United States and southern British Columbia

Tertiary meteoric hydrothermal systems and their relation to ore deposition, northwestern United States and southern British Columbia

Geochemistry of Magnetite from Hydrothermal Ore Deposits and Host Rocks of the Mesoproterozoic Belt Supergroup, United States

Paleogene postcompressional intermontane basin evolution along the frontal Cordilleran fold-and-thrust belt of southwestern Montana

Contact Info

Product

Resources

About