Evidence for thermal erosion of basalt and hybridization of komatiite at Kambalda, Western Australia

Conference · Tue Jan 01 00:00:00 EST 1985 · Geol. Soc. Am., Abstr. Programs; (United States)

OSTI ID:6195775

Lesher, C M

Archean komatiite-associated Ni-sulfide ores in Western Australia are hosted by cumulate metakomatiites and are localized in footwall embayments. Structural, stratigraphical, and volcanological studies of the type-examples of these deposits at Kambalda, Western Australia suggest i) that the host units represent linear lava conduits and ii) that the embayments are volcanic features, modified by deformation. The sulfide ore are interpreted to have formed by assimilation of sulfidic, cherty sediments beneath the thermally-active lava conduits. Transgressive magmatic contacts between massive sulfide and pillowed metabasalt provide unequivocal evidence for erosion of basalt by highly thermally conductive massive sulfides. Evidence for thermal erosion of basalt by komatiite is more equivocal as contacts between the two lithologies are normally recrystallized and marked by chloritic metasomatic reaction zones. Thermal erosion channels produced experimentally by Huppert et al. (1984) are morphologically similar to the embayments at Kambalda, but it is unlikely that the embayments in these deposits have been generated by thermal erosion, for several reason: 1) Some embayments contain uneroded metasediments and predate emplacement of the ores and host units. 2) Some embayments appear to be broadly stratigraphically conformable within the footwall metabasalt sequence. 3) Some embayments are elliptical in outline and could not have formed by thermal erosion beneath a lava conduit. The embayments probably represent volcanic-topographic irregularities in the surface of the footwall basalt that have been variably modified by thermal erosion.

• Research Organization: Univ. of Alabama, University (USA)
• OSTI ID: 6195775
• Report Number(s): CONF-8510489-
• Journal Information: Geol. Soc. Am., Abstr. Programs; (United States), Vol. 17; Conference: 98. annual meeting of the Geological Society of America, Orlando, FL, USA, 28 Oct 1985
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
NICKEL ORES
MINERALIZATION
PETROGENESIS
PETROLOGY
WESTERN AUSTRALIA
BASALT
GEOLOGIC FAULTS
MAGMATISM
PRECAMBRIAN ERA
STRATIGRAPHY
SULFIDE MINERALS
VOLCANISM
AUSTRALASIA
AUSTRALIA
GEOLOGIC AGES
GEOLOGIC FRACTURES
GEOLOGIC STRUCTURES
GEOLOGY
IGNEOUS ROCKS
MINERALS
ORES
ROCKS
VOLCANIC ROCKS
580300* - Mineralogy
Petrology
& Rock Mechanics- (-1989)