Rare earth element patterns and crustal evolution--II. Archean sedimentary rocks from Kalgoorlie, Australia

Details Rare earth element patterns and crustal evolution--II. Archean sedimentary rocks from Kalgoorlie, Australia Rare earth element patterns and crustal evolution--II. Archean sedimentary rocks from Kalgoorlie, Australia

Feb 1977

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1977gecoa..41..225n&link_type=abstract

Geochimica et Cosmochimica Acta, vol. 41, Issue 2, pp.225-231

Other

18

Scientific paper

REE data, with major element and other trace element data are reported for a suite of Archean sedimentary rocks (2800 million years old) from Kalgoorlie, Western Australia. The REE patterns fall into two groups with LREE/ HREE ratios of 6 and 15, respectively. The first group have either no Eu anomaly relative to chondrites, or a positive Eu anomaly, in contrast to the pronounced Eu depletion (Eu/Eu ~ 0.67) shown by younger (Post-Archean) sedimentary rocks. The problem of positive Eu enrichment relative to chondritic patterns, is examined by analysing a suite of Devonian greywackes, derived from calc-alkaline volcanic rocks. Some of these samples also show positive Eu anomalies, attributable to local accumulation of feldspar. This explanation is preferred to models involving an early anorthositic crust. The group of samples showing heavy REE depletion patterns (complementary to those observed in garnet) appear to be derived from adjacent Na-rich granites which display identical REE patterns. Locally abundant K-rich granites do not appear to have made any contribution to the Archean sedimentary rocks. The majority of the sedimentary rocks have REE patterns indistinguishable from those of recent island arc calc-alkaline rocks, and so could constitute evidence that the Archean crust was principally formed by processes analogous to present day island-arc type volcanism. However, similar REE patterns may be produced by an appropriate mixture of the common bimodal tholeiitic-felsic igneous suite commonly observed in Archean terrains. The REE data presented here do not distinguish between these two models.

Affiliated with

Also associated with

No associations

Rating

Rare earth element patterns and crustal evolution--II. Archean sedimentary rocks from Kalgoorlie, 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 Rare earth element patterns and crustal evolution--II. Archean sedimentary rocks from Kalgoorlie, Australia, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Rare earth element patterns and crustal evolution--II. Archean sedimentary rocks from Kalgoorlie, Australia will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-799681