A comparison of geochemical exploration techniques and sample media within accretionary continental margins: an example from the Pacific Border Ranges, Southern Alaska, U.S.A.

Sutley, S.J.; Goldfarb, Richard J.; O'Leary, R. M.; Tripp, R.B.

doi:10.1016/0375-6742(90)90029-a

Cited by 2 publications

(2 citation statements)

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“…in consideration of many factors (e.g. Butt & Zeegers, 1989; Sutley et al , 1990). The sample density was a 100‐m interval for lines and 20 m for sampling sites and every sample (63 samples in total), approximately 1.0 kg each, was mixed with the collection from the top of C horizons of two 10‐m‐apart hand‐excavated pits (25–125 cm deep).…”

Section: Methodology Of Geochemical Explorationmentioning

confidence: 99%

Characteristics of the Bumo Gold Field, Hainan Island, China and Gold Exploration Through Soil Geochemical Surveys

et al. 2007

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The Bumo gold deposit is a low‐sulfide quartz vein type deposit, situated in the west of Hainan Island, approximately 25 km southeast of Dongfang City (termed Basuo in alias). Tectonically, the SW‐NE‐oriented Gezhen Ductile‐Shearing Zone was largely attenuated in Bumo. It is hosted by gneisses and schists of Proterozoic age (locally called the Baoban Group), but the radiometric age of ores mainly is Jurassic–Cretaceous, being coeval to the regional metallogenesis along the Eurasian margin. The affinity with the Phanerozoic orogenic gold deposits is indicated by low salinity (2.4 wt% NaCl–10.3 wt% NaCl), intermediate temperature (150–300°C) and appropriate δ18O value (approximately 7–11‰). The gold metal tonnage, proved previously, within an area smaller than 1.0 km2 in the gold belt II amounted to 11.59 t, with the average gold grades for the major Au quartz veins (7 and 8) in this belt of 52.7 and 71.1 g/t, respectively. This shows significant enrichment of gold and an unusual “nugget effect”. A ring structure, mainly represented by ridges, valleys, dikes, big bull quartz veins and lithological borders or pertinent faults, marks the gold field, and its origin was linked to a possible magmatic diapir. It was viewed as macroscopic evidence that the dip angles of strata tend to decline gradually from deeper ones in the center area to nearly horizontal in the outskirts, and certain intrusion‐affiliated elements such as Bi, As and W are considerably abundant in soil samples. Two areas, namely the area A (3.06 km2) in the outskirts of the ring structure or in northeastern Bumo and the area B (1.32 km2) in the field center or to the west of the gold belts I and II, were selected for the geochemical survey in a 50 × 50‐m sampling grid. The analytical results of the samples from horizon C and in a −80 mesh size showed that the average contents of Bi, As and W amounted to 0.55, 19.3 and 3.67 ppm in the area A (1225 samples) and to 0.79, 68.3 and 4.14 ppm in the area B (529 samples), respectively. This geochemical exploration led to the discovery of several Au quartz veins in both areas A and B, which also manifested an Au nugget effect (the average Au grades between 50 and 100 g/t) in spite of their limited scales (from a couple of centimeters to 50 cm wide and from several meters to 15 m long). A mylonite zone in area A was also found by this study. An intimate spatial correlation between a lithological border (gneiss and schist or pegmatite) or the mylonite zone and Au anomalies indicates an important prospect for further gold exploration.

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Section: Methodology Of Geochemical Explorationmentioning

confidence: 99%

Characteristics of the Bumo Gold Field, Hainan Island, China and Gold Exploration Through Soil Geochemical Surveys

et al. 2007

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“…Stednick and Riese (1987) discussed biogeochemistry for exploration in Colorado; Williams et al (1987) discussed the exploration significance of ammonium in silicates. Sutley et al (1990) reviewed the utility of various exploration techniques in Alaska.…”

Section: Models: Exploration and Laboratory Studiesmentioning

confidence: 99%

Metallogenesis

Burt

1991

Reviews of Geophysics

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A comparison of geochemical exploration techniques and sample media within accretionary continental margins: an example from the Pacific Border Ranges, Southern Alaska, U.S.A.

Cited by 2 publications

References 11 publications

Characteristics of the Bumo Gold Field, Hainan Island, China and Gold Exploration Through Soil Geochemical Surveys

Characteristics of the Bumo Gold Field, Hainan Island, China and Gold Exploration Through Soil Geochemical Surveys

Metallogenesis

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