Geochemistry of Archean shales from the Pilbara Supergroup, Western Australia

Details Geochemistry of Archean shales from the Pilbara Supergroup, Western Australia Geochemistry of Archean shales from the Pilbara Supergroup, Western Australia

Jul 1983

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1983gecoa..47.1211m&link_type=abstract

Geochimica et Cosmochimica Acta, vol. 47, Issue 7, pp.1211-1222

Computer Science

15

Scientific paper

Archean clastic sedimentary rocks are well exposed in the Pilbara Block of Western Australia. Shales from turbidites in the Gorge Creek Group ( ca . 3.4 Ae) and shales from the Whim Creek Group ( ca. 2.7 Ae) have been examined. The Gorge Creek Group samples, characterized by muscovite-quartzchlorite mineralogy, are enriched in incompatible elements (K, Th, U, LREE) by factors of about two, when compared to younger Archean shales from the Yilgarn Block. Alkali and alkaline earth elements are depleted in a systematic fashion, according to size, when compared with an estimate of Archean upper crust abundances. This depletion is less notable in the Whim Creek Group. Such a pattern indicates the source of these rocks underwent a rather severe episode of weathering. The Gorge Creek Group also has fairly high B content (85 ± 29 ppm) which may indicate normal marine conditions during deposition. Rare earth element (REE) patterns for the Pilbara samples are characterized by light REE enrichment ( La N / Yb N 7.5) and no or very slight Eu depletion ( Eu / Eu * = 0.82 - 0.99). A source comprised of about 80% felsic igneous rocks without large negative Eu-anomalies (felsic volcanics, tonalites, trondhjemites) and 20% mafic-ultramafic volcanics is indicated by the trace element data. Very high abundances of Cr and Ni cannot be explained by any reasonable provenance model and a secondary enrichment process is called for.

Affiliated with

Also associated with

No associations

Rating

Geochemistry of Archean shales from the Pilbara Supergroup, Western Australia does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Geochemistry of Archean shales from the Pilbara Supergroup, Western Australia, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Geochemistry of Archean shales from the Pilbara Supergroup, Western Australia will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1627506