Geological and geochemical specialization of ore-bearing formations

Domestic geology ◽

10.47765/0869-7175-2021-10021 ◽

2021 ◽

pp. 48-51

Author(s):

Eugene FILATOV ◽

Ludmila FILATOVA

Keyword(s):

Structural Material ◽

Volcanic Rocks ◽

Potassium Content ◽

Geochemical Mapping ◽

Quantitative Estimates ◽

Silicic Volcanic ◽

Geological Formations ◽

Geochemical Specialization

The geochemical and metallogenic specialization and zoning of structural-material complexes are analyzed. In the general systematic operational circuit of metallogenic forecasting and geological prospecting, processing the data on the geochemical specialization of geological formations and their constituents make it possible to perform a formational interpretation of anomalous geochemical fields revealed in the course of multipurpose geological and geochemical mapping; to subdivide the explored areas by the types of geological formations differing by their ore-bearing potential, with allocation of the most productive subformations, phases, and facies; and to provide quantitative estimates of the forecasted resources. Geochemical criteria of the ore-bearing potential of geological formations consist, first of all, in stable correlations between petrochemical features of ore-bearing rocks and their corresponding fluctuations of the ore composition (for example, the correlation of the potassium content of ore-hosting silicic volcanic rocks of the ore-bearing volcanogenic geological formations with the Cu/Pb ratio in ores of various types of deposits of the VMSD formational family). These criteria are to be taken into account in regional and local assessments of the perspective ore-bearing potential of geological formations.

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Decision letter for "Petrogenesis of highly differentiated I-type volcanic rocks: Reinjection of high-temperature magma-An example from Suolun silicic volcanic rocks, central Great Xing'an Range, China"

10.1002/gj.3838/v3/decision1 ◽

2020 ◽

Keyword(s):

High Temperature ◽

Volcanic Rocks ◽

Silicic Volcanic ◽

Great Xing’An Range

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Regionally continuous Miocene rhyolites beneath the eastern Snake River Plain reveal localized flexure at its western margin: Idaho National Laboratory and vicinity

The Mountain Geologist ◽

10.31582/rmag.mg.57.3.241 ◽

2020 ◽

Vol 57 (3) ◽

pp. 241-270

Author(s):

Kyle L. Schusler ◽

David M. Pearson ◽

Michael McCurry ◽

Roy C. Bartholomay ◽

Mark H. Anders

Keyword(s):

Volcanic Rocks ◽

Snake River Plain ◽

North American Plate ◽

Snake River ◽

Trace Element Geochemistry ◽

Deep Borehole ◽

Age Progression ◽

Western Margin ◽

Silicic Volcanic ◽

River Plain

The eastern Snake River Plain (ESRP) is a northeast-trending topographic basin interpreted to be the result of the time-transgressive track of the North American plate above the Yellowstone hotspot. The track is defined by the age progression of silicic volcanic rocks exposed along the margins of the ESRP. However, the bulk of these silicic rocks are buried under 1 to 3 kilometers of younger basalts. Here, silicic volcanic rocks recovered from boreholes that penetrate below the basalts, including INEL-1, WO-2 and new deep borehole USGS-142, are correlated with one another and to surface exposures to assess various models for ESRP subsidence. These correlations are established on U/Pb zircon and 40Ar/39Ar sanidine age determinations, phenocryst assemblages, major and trace element geochemistry, δ18O isotopic data from selected phenocrysts, and initial εHf values of zircon. These data suggest a correlation of: (1) the newly documented 8.1 ± 0.2 Ma rhyolite of Butte Quarry (sample 17KS03), exposed near Arco, Idaho to the upper-most Picabo volcanic field rhyolites found in borehole INEL-1; (2) the 6.73 ± 0.02 Ma East Arco Hills rhyolite (sample 16KS02) to the Blacktail Creek Tuff, which was also encountered at the bottom of borehole WO-2; and (3) the 6.42 ± 0.07 Ma rhyolite of borehole USGS-142 to the Walcott Tuff B encountered in deep borehole WO-2. These results show that rhyolites found along the western margin of the ESRP dip ~20º south-southeast toward the basin axis, and then gradually tilt less steeply in the subsurface as the axis is approached. This subsurface pattern of tilting is consistent with a previously proposed crustal flexural model of subsidence based only on surface exposures, but is inconsistent with subsidence models that require accommodation of ESRP subsidence on either a major normal fault or strike-slip fault.

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