Mineral resources of the Idaho Primitive Area and vicinity, Idaho

Cater, Fred W.; Pinckney, Darrell M.; Hamilton, Warren; Parker, Richard L.; Weldin, R.D.; Close, T.J.; Zilka, N.T.

doi:10.3133/ofr7342

Cited by 23 publications

(9 citation statements)

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“…The area is underlain by Challis Volcanics which have been intruded by various phases of the Idaho Batholith. Challis Volcanics consist of tuffs and flows of rhyolitic to andesitic rock of Eocene age (Ross 1934;Cater et al 1973;Knowles and Bennett 1978). The stream sites examined during this study lie on a mixture of Idaho Batholith and Challis Volcanics rocks.…”

Section: Description Of the Study Areamentioning

confidence: 99%

Water quality, substratum and biotic responses of five central Idaho (USA) streams during the first year following the Mortar Creek fire

Minshall¹,

Brock²,

Andrews³

et al. 2001

Int. J. Wildland Fire

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The Mortar Creek Fire burned 26 000 ha of mixed-conifer Rocky Mountain forest in July-August 1979. Changes in burn stream conditions were examined relative to reference streams for various ecological factors on two to six occasions, from October 1979 to August 1980. Factors included major ions and nutrients, suspended and benthic particulate matter, periphyton (algae), and macroinvertebrates. Elevated levels of most dissolved chemicals in the burn streams were evident soon after the fire and again during spring runoff. However, there were no major disruptions in the relative composition of cations (and presumably of anions also) in the burn streams during the study. Concentration (mg/L) and load (g/s) of some constituents were higher (e.g. NO 3 -N) and of others (e.g. Ca) were lower in the burn than in the reference streams during spring runoff, depending on whether they were normally under biological or geological control, respectively. Suspended sediment and particulate organic matter generally were higher in burn streams, especially during snow-melt runoff or following heavy rain storms. Benthic organic matter was higher in burn streams and was mainly charcoal, compared to the usual leaf litter found in the reference streams. Fine sediments increased and periphyton decreased in the burn streams. The fire increased the sensitivity of the burn streams to more routine smaller-scale disturbances, such as rainstorms, which had major impacts on the burn streams but not on the reference streams. The macroinvertebrate assemblage showed little direct effect from the fire but was severely altered in composition and abundance by the subsequent runoff, scouring, and channel alteration initiated by spring runoff. The burn streams showed considerable individuality in their response to fire depending on the particular set of conditions to which they were exposed. s o f I d a h o s t r e a ms t h e f i r s t y e a r a f t e r w i l d f i r e WF 0 1 0 1 7 G . W a y n e M i n s h a l lA , J a m e s T . B r o c k , D o u g l a s A . A n d r e w s , a n d C h r i s t o p h e r T . R o b i n s o n

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Section: Description Of the Study Areamentioning

confidence: 99%

Water quality, substratum and biotic responses of five central Idaho (USA) streams during the first year following the Mortar Creek fire

Minshall¹,

Brock²,

Andrews³

et al. 2001

Int. J. Wildland Fire

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“…Several petrographic features distinguish these plutons from the older granitoid rocks and are indicative of an epizonal emplacement, for example, high heat generation [Swanberg and Blackwell, 1973] and common miarolitic cavities [Ross, 1934]. Some of these plutons intrude approximately coeval Eocene rocks of the Challis Volcanics [Ross, 1934' Hamilton and Myers, 1967' Cater et al, 1973Armstrong, 1974], large exposures of which occur east of the Idaho batholith (Figure 1). Most of the other Tertiary plutons are inferred to be Eocene on the basis of isotopic ages [Armstrong, 1974] and their lithologic similarity to the subvolcanic intrusions.…”

Section: Geologic Settingmentioning

confidence: 99%

Magnetic properties of granitic rocks from the southern half of the Idaho Batholith: Influences of hydrothermal alteration and implications for aeromagnetic interpretation

Criss¹,

Champion²

1984

J. Geophys. Res.

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The measured magnetic susceptibilities of rocks from more than 600 outcrops in the southern Idaho batholith have a good spatial correspondence with the observed intensities of magnetic anomalies. Koenigsberger ratios are low (≤0.3) in 75% of cored samples, indicating that remanent magnetizations are unimportant relative to induced magnetizations (which are related to susceptibilities) in aeromagnetic anomaly interpretations in this region. Extremely low susceptibilities (χ<5×10−5 cgs) occur in the leucocratic granite and granodiorite plutons that comprise the ∼7000‐km2 interior of the batholith, and there is a corresponding broad aeromagnetic low over the same region. Several zones of “high” susceptibility rock (χ>25×10−5) within the eastern and western parts of the batholith are the sources of positive aeromagnetic anomalies; the associated lithologies include Mesozoic tonalite and granodiorite, as well as a diverse Tertiary group of epizonal stocks and batholiths. Intense meteoric‐hydrothermal activity associated with the emplacement of these Tertiary plutons caused a reduction in χ in some rocks, although coarse igneous magnetite is surprisingly resistant to hydrothermal corrosion and oxidation. However, under conditions of lower water/rock ratios, a significant increase in χ commonly occurred in the leucocratic plutons, generally reflecting growth of hydrothermal magnetite. Because the measured susceptibilities do not necessarily represent more than the uppermost part of the 14‐ to 20‐km thick crust that gives rise to magnetic anomalies, an apparent discordance between susceptibility measurements and susceptibilities inferred from aeromagnetic data can occur. Such discordance patterns occur near the margins of the batholith, where granitic rocks are thin, and also in hydrothermally altered regions, where subsurface Tertiary plutons are present. Magnetic models suggest that the Idaho batholith thickens to ∼20 km in its east‐central part, which is underlain by enormous Tertiary intrusive bodies.

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“…Leucocratic granite, described as leucocratic quartz monzonite by , as aplite by Cater and others (1973), and as aplitic quartz monzonite by Anderson (1947), occurs as dikes, sill-like masses, and irregular stocks that are resistant to erosion and tend to form high points on ridges. Rubbly weathered scree from the high exposures may be extensive on lower slopes and may give the impression of being derived from larger exposures than actually exist.…”

Section: Leucocratic Granitementioning

confidence: 99%

“…He also described and subdivided the Challis Volcanics and the Casto Volcanics. Cater and others (1973) mapped part of the diorite along the Rapid River (fig. Fl, area H) and noted that the Casto Volcanics are probably altered units of the Challis Volcanics; he abandoned the name "Casto Volcanics!'…”

Section: Previous Workmentioning

confidence: 99%

See 1 more Smart Citation

Symposium on the geology and mineral deposits of the Challis 1° x 2° quadrangle, Idaho

McIntyre¹

1985

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Al. Map showing selected geologic features 4 A2. Simplified geologic map 6 A3. Map showing the trans-Challis fault system 9 A4. Map showing mines and prospects 9 A5. Diagram showing number of mineral deposits arranged by commodity 10 A6. Chart comparing significance and chance of discovery of mineral commodities 10 A7. Diagram showing temporal relationships of the major geologic and tectonic features and metallic mineral deposits 11 A8. Map showing mining districts and selected principal mines 12 A9-A16. Maps showing mines and prospects for: A9. Fluorspar 15 A10. Mercury 16 All. Gold 18 A12. Silver 19 A13. Molybdenum 20 A14. Zinc 21 A15. Lead 22 A16. Copper 23 A17. Graph showing production of gold and silver 24 A18. Graph showing production of copper, lead, and zinc 25TABLE Al. Mineral commodities produced from or present in anomalous concentrations in the Challis quadrangle 9 Challis 1°x2° Quadrangle, Idaho

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Mineral resources of the Idaho Primitive Area and vicinity, Idaho

Cited by 23 publications

References 0 publications

Water quality, substratum and biotic responses of five central Idaho (USA) streams during the first year following the Mortar Creek fire

Water quality, substratum and biotic responses of five central Idaho (USA) streams during the first year following the Mortar Creek fire

Magnetic properties of granitic rocks from the southern half of the Idaho Batholith: Influences of hydrothermal alteration and implications for aeromagnetic interpretation

Symposium on the geology and mineral deposits of the Challis 1° x 2° quadrangle, Idaho

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