New Zealand Journal of Geology and Geophysics abstracts
Provenance and depositional setting of pre-Late Jurassic turbidite complexes
in Patagonia, Chile
Víctor Faúndez
Francisco Hervé
Juan Pablo Lacassie
Departamento de Geología
Universidad de Chile
Casilla 13518, Correo 21
Santiago, Chile
Abstract Metaturbidites of the Eastern Andes Metamorphic
Complex, which crop out east of the Mesozoic-Cenozoic Patagonian Batholith,
show significant differences in modal and chemical composition with those
of the Duque de York Complex which crop out west of the batholith. The modal
quartz content of the sandstones of the former is larger and does not spread
out of the Transitional Continental field in QFL diagrams as does that of
the latter. In the geochemical discrimination diagrams, sandstones from both
units plot in distinct fields with little or no overlap. These features strongly
suggest different provenance areas and depositional settings. The Eastern
Andes Metamorphic Complex was deposited in a basin located on a passive continental
margin, and the source area for the clastic rocks had cratonic affinities.
By contrast, the rocks of the Duque de York Complex indicate deposition in
an active continental margin, which included sedimentary, plutonic, and volcanic
rocks, associated with a subduction zone and/or a strike-slip setting. These
results suggest that the two units are not coeval, and that they represent
deposition before and after the establishment of the active continental margin
at the Pacific rim of Gondwanaland during the late Paleozoic or early Mesozoic.
Keywords sedimentary provenance; tectonic setting;
metaturbidites; pre-Late Jurassic; Patagonian Andes; Chile
G01001 Received 23 January 2001; accepted 12 August 2002; published 6
December 2002
New Zealand Journal of Geology & Geophysics, 2002, Vol. 45: 411-425
0028-8306/02/4504-0411 $7.00/0 © The Royal Society of New Zealand
2002
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