147 Sm--- 143 Nd, 146 Sm--- 142 Nd systematics of early Archaean rocks and implications for crust-mantle evolution

Details 147 Sm--- 143 Nd, 146 Sm--- 142 Nd systematics of early Archaean rocks and implications for crust-mantle evolution 147 Sm--- 143 Nd, 146 Sm--- 142 Nd systematics of early Archaean rocks and implications for crust-mantle evolution

Sep 1996

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=1996gecoa..60.3513r&link_type=abstract

Geochimica et Cosmochimica Acta, vol. 60, Issue 18, pp.3513-3520

Physics

5

Scientific paper

Combined high precision 147 Sm--- 143 Nd, 146 Sm--- 142 Nd data have been obtained for two early Archaean (pre-3.8 Ga) samples (a 4.0 ± 0.2 Ga meta-komatiite and an approximately 3.9 Ga orthogneiss) from the northern Labrador segment of the North Atlantic Craton. The samples have t 143Nd values at 3.8 Ga of -4.0 and +1.4, respectively, however t 142Nd 142Nd for both samples is indistinguishable from the bulk earth value. For the sample with t 143Nd - 4.0, t 142Nd is + 0.03 ± 0.14, which suggests that it was derived from a source which differentiated from the primitive mantle at between 4.1 and 4.3 Ga. 14 Sm--- 143 Nd and 146 Sm--- 142 Nd data are also presented for a kyanite eclogite xenolith from a 350 Ma kimberlite from Yakutia, Siberia. 142Nd / 144 Nd for this sample is also within error of the bulk earth value. Eclogite xenoliths, such as those from kimberlite pipes, are, therefore, unlikely to be residues of crystallization of a pre-4.4 Ga magma ocean, but instead may represent fragments of post-4.3 Ga oceanic crust incorporated into the subcontinental lithospheric mantle. The absence of widespread variations in 142 Nd/ 144 Nd in early Archaean rocks supports models in which the volume of the depleted mantle has grown through time. Continuous growth of the depleted mantle and continental crust at the expense of the primordial mantle at between 4.56 and 4.0 Ga can generate variations in t 143Nd and account for the absence of detectable variations in 142 Nd/ 144 Nd in most early Archaean rocks.

Affiliated with

Also associated with

No associations

Rating

147 Sm--- 143 Nd, 146 Sm--- 142 Nd systematics of early Archaean rocks and implications for crust-mantle evolution 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 147 Sm--- 143 Nd, 146 Sm--- 142 Nd systematics of early Archaean rocks and implications for crust-mantle evolution, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and 147 Sm--- 143 Nd, 146 Sm--- 142 Nd systematics of early Archaean rocks and implications for crust-mantle evolution will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-1462697