Crustal setting of mafic and ultramafic rocks and associated ore deposits of the Caribbean region

Case, James E.

doi:10.3133/ofr80304

Cited by 10 publications

(4 citation statements)

References 135 publications

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“…The approximate extent of the metamorphic craton in northern Central America is shown by the 30-km depth contour to the M-discontinuity [20] as shown in Fig. 1.…”

Section: Basement Rockmentioning

confidence: 99%

Source of lead in Central American and Caribbean mineralization, II. Lead isotope provinces

Cumming

Kesler

Krstić

1981

Earth and Planetary Science Letters

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In an earlier study of Mesozoic and Cenozoic mineralization in Central America and the Caribbean region, we found that lead isotopic compositions of deposits in northern Central America, which is underlain by a pre-Mesozoic craton, ranged to higher 2°6pb/Z°aPb and 2°7pb/Z°4pb compositions than did deposits from elsewhere in the region, where the basement is Mesozoic oceanic material. Using 16 analyses for 12 new deposits, as well as new analyses for 11 of the samples studied previously, we have found that lead isotopic compositions correlate closely with crustal type but show little or no correlation with depth to the M-discontinuity. The deposits are divisible into three main groups including (in order of increasing 2°7pb/2°4pb and 2°8pb/Z°4pb ratio): (1) deposits in southern Central America and all deposits in the Greater Antilles except Cuba; (2) all deposits in northern Central America; and (3) the Cuban deposits. Southern Central American and Caribbean lead is higher in 2°vpb/Z°4pb and 2°spb/2°4pb than most mid-ocean ridge basalts but could have been derived directly or indirectly from undepleted mantle. Northern Central America can be divided into the Maya block, which belongs to the Americas plate, and the Chortis block, which belongs to the Caribbean plate. Maya block deposits fall along a linear array whereas those of the Chortis block (except the Monte Cristo deposit) form a cluster. These results suggest that the Maya block is underlain by crust or mantle with a large range of U/Pb and Th/U ratios, whereas the Chortis block basement is more homogeneous. Two-stage model calculations indicate an age of about 2280-+-310 m.y. for the Maya block basement, although no such rocks are known in the region. Comparison of the Chortis block data to our recently published lead isotopic analyses of Mexican deposits shows considerable similarities suggesting that the Chortis block could have been derived from Mexico.

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“…The approximate extent of the metamorphic craton in northern Central America is shown by the 30-km depth contour to the M-discontinuity [20] as shown in Fig. 1.…”

Section: Basement Rockmentioning

confidence: 99%

Source of lead in Central American and Caribbean mineralization, II. Lead isotope provinces

Cumming

Kesler

Krstić

1981

Earth and Planetary Science Letters

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“…For land areas, where Bouguer anomalies exceed +50 mGals, oceanic or "transitional" crust is suspected. Anomalies greater than +50 mGals were used by Case and others (1971) to postulate oceanic crust on land in western Colombia, and the inferences from gravity data were substantiated by subsequent refraction studies of Project Narino (see summary by Case, 1980). Deep refraction lines both parallel to and normal to the regional tectonic grain are needed to resolve such questions of crustal properties in this area of high seismic risk, active volcanism, and large resource potential for oil and gas and metallic minerals.…”

Section: Some Regional Crustal Inferencesmentioning

confidence: 98%

Gravity anomaly and interpretation map of the Chignik and Sutwik Island quadrangles, Alaska

Case¹,

Barnes²,

Detterman³

et al. 1981

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“…Case ( 1980). - -------------------------GRNR, ANGR, MMRL Guatemala-continued Reference Case ( 1980). Haldemann and others (1982).…”

Section: Domentioning

confidence: 99%

“…Linchenat and Shirokova (1964). Case ( 1980). - -------------------------GRNR, ANGR, MMRL Guatemala-continued Reference Case ( 1980).…”

Section: Domentioning

confidence: 99%

International strategic minerals inventory summary report; cobalt

Crockett¹,

Chapman²,

Forrest³

1987

Circular

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Crustal setting of mafic and ultramafic rocks and associated ore deposits of the Caribbean region

Abstract: and 40 have been grouped randomly on six oversize sheets. Individual figures can be cut apart as needed. Crustal setting of mafic and ultramafic rocks and associated ore deposits of the Caribbean region

Cited by 10 publications

References 135 publications

Source of lead in Central American and Caribbean mineralization, II. Lead isotope provinces

Source of lead in Central American and Caribbean mineralization, II. Lead isotope provinces

Gravity anomaly and interpretation map of the Chignik and Sutwik Island quadrangles, Alaska

International strategic minerals inventory summary report; cobalt

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