Sedimentologic and tectonic aspects of the Archean Limpopo belt

Conference · Tue Jan 01 04:00:00 EST 1985 · Geol. Soc. Am., Abstr. Programs; (United States)

OSTI ID:6613435

Erikkson, K A; Kidd, W S.F.

There are marked lithic differences between the central Limpopo belt and other well-studied Archean high-grade and greenstone-granitoid terranes, in particular the presence, in thick sections of supracrustals including approx. 15% of each of 1) carbonate and calc-silicate rocks and 2) pure metaquartzite, often fuchsite-bearing, with the lithic character of quartz arenite, not metachert. Isotopic ages suggest these sediments are 3.3-3.5 Ga old. The sequence and distribution of lithic, plutonic, metamorphic, and structural events in the Limpopo belt resembles that in younger orogens where there has been rifting of continental lithosphere, deposition of sediments at an Atlantic-type margin, then convergence and collision with another continental block. The southern margin of the central Limpopo belt is a wide (20 km) zone of vertically-dipping, horizontally-lineated mylonites, clearly representing the deeper ductile levels of a major strike-slip fault. This fault resembles large strike-slip systems that allow tectonic escape during collision in young orogenic belts. The authors conclude that continental fragments large enough to provide a substrate for significant platform arenite and carbonate sedimentation existed by 3.3-3.5 Ga, and that Tibetan-Himalayan style collisional tectonics greater than or equal to 2.6 Ga ago accounts for the large-scale relationships between the Limpopo belt and the adjacent Archean greenstone-granitoid terrane cratons. By inference, other more fragmentary Archean gneissic terranes may have once been part of such collisional zones.

• Research Organization: State Univ. of New York, Albany (USA)
• OSTI ID: 6613435
• Report Number(s): CONF-8510489-
• Conference Information: Journal Name: Geol. Soc. Am., Abstr. Programs; (United States) Journal Volume: 17
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580100* -- Geology & Hydrology-- (-1989)
580201 -- Geophysics-- Seismology & Tectonics-- (1980-1989)
AGE ESTIMATION
FEDERAL REGION I
GEOLOGIC FAULTS
GEOLOGIC FRACTURES
GEOLOGIC HISTORY
GEOLOGIC STRATA
GEOLOGIC STRUCTURES
INCLINED STRATA
ISOTOPE DATING
LITHOLOGY
METAMORPHIC ROCKS
METAMORPHISM
NORTH AMERICA
PLATE TECTONICS
RIFT ZONES
ROCKS
SEDIMENTARY ROCKS
SEDIMENTATION
TECTONICS
USA