Two-stage evolution of mantle peridotites from the Stalemate Fracture Zone, northwestern Pacific.

Krasnova, E. A., Portnyagin, Maxim V. , Silantyev, S. A., Hoernle, Kaj A. and Werner, Reinhard (2013) Two-stage evolution of mantle peridotites from the Stalemate Fracture Zone, northwestern Pacific. Geochemistry International, 51 (9). pp. 683-695. DOI 10.1134/S0016702913080028.

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This paper reports the results of a mineralogical study of 14 mantle peridotite samples dredged in 2009 from the eastern slope of the northwestern segment of the Stalemate Ridge in the northwestern Pacific during cruise SO201-KALMAR Leg 1b of the R/V Sonne. The sample collection included four serpentinized and silicified dunites and ten variably serpentinized lherzolites. The compositions of primary minerals (clinopyroxene, orthopyroxene, and spinel) change systematically from the lherzolites to dunites. Spinel from the lherzolites shows higher Mg# and lower Cr# values (0.65-0.68 and 0.26-0.33, respectively) compared with spinel from the dunites (Mg# = 0.56-0.64 and Cr# = 0.38-0.43). Clinopyroxene from the lherzolites is less magnesian (Mg# = 91.7-92.4) than clinopyroxene from dunite sample DR37-3 (Mg# = 93.7). Based on the obtained data, it was concluded that the lherzolites of the Stalemate Fracture Zone were derived by 10-12% near-fractional melting of a DMM-type depleted mantle reservoir beneath the Kula-Pacific spreading center. The dunites were produced by interaction of residual lherzolites with sodium- and titaniumrich melt and are probably fragments of a network of dunite channels in the shallow mantle. The moderately depleted composition of minerals clearly distinguishes the lherzolites from the strongly depleted peridotites of the East Pacific Rise and indicates the existence of slow-spreading mid-ocean ridges in the Pacific Ocean during the Cretaceous-Paleogene.

Document Type: Article
Additional Information: WOS:000323664100001
Keywords: mantle peridotite; oceanic lithosphere; magmatism; partial melting
Research affiliation: OceanRep > GEOMAR > FB4 Dynamics of the Ocean Floor > FB4-MUHS
Refereed: Yes
Open Access Journal?: No
Publisher: Springer
Projects: KALMAR, Future Ocean
Date Deposited: 19 Sep 2013 11:23
Last Modified: 06 Nov 2017 10:57

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