Platinum group elements and geochemistry of altered oceanic crust of ODP Hole 140-504B

DOI

Primary chemical heterogeneity in the sheeted dike complex in Deep Sea Drilling Project Hole 504B makes these rocks unsuitable for conventional mass balance calculations in determining element mobility associated with hydrothermal alteration. Due to the original heterogeneity and variable degrees of fractionation in the dikes, an appropriate reference sample on which calculations can be based is difficult to find. Therefore, the use of incompatible element ratios is developed to evaluate geochemical changes during alteration(s). For example, on a Zr/Yb-La/Yb plot, scatter along a straight line suggests tapping of a variably depleted mantle source and deviation from the line suggests element mobility (gain or loss). Using this method, our data indicates that the hydrothermal evolution of the sheeted dike complex was accompanied by significant loss of Cu, Zn, and Ti and some loss of La.The sheeted dike complex has low platinum group element (PGE) concentrations and steep PGE patterns, typical of mid-ocean ridge basalts (MORBs) on the global scale. We propose that the unusual PGE patterns of MORBs cannot be entirely generated by a partial melting and sulfide segregation model; instead, these patterns in part must have been inherited from their mantle source. The Au data show no evidence for mobilization during hydrothermal alteration of the dikes.

Supplement to: Gorton, Michael P; Schandl, Eva S; Naldrett, AJ (1995): Platinum group element (PGE) concentrations in a sheeted dike complex and geochemical changes during alteration of the lowermost part of a 2-km-thick oceanic crust, Hole 504B. In: Erzinger, J; Becker, K; Dick, HJB; Stokking, LB (eds.), Proceedings of the Ocean Drilling Program, Scientific Results, College Station, TX (Ocean Drilling Program), 137, 199-205

Identifier
DOI https://doi.org/10.1594/PANGAEA.806614
Related Identifier IsSupplementTo https://doi.org/10.2973/odp.proc.sr.137140.012.1995
Metadata Access https://ws.pangaea.de/oai/provider?verb=GetRecord&metadataPrefix=datacite4&identifier=oai:pangaea.de:doi:10.1594/PANGAEA.806614
Provenance
Creator Gorton, Michael P; Schandl, Eva S; Naldrett, AJ
Publisher PANGAEA
Publication Year 1995
Rights Creative Commons Attribution 3.0 Unported; https://creativecommons.org/licenses/by/3.0/
OpenAccess true
Representation
Resource Type Supplementary Publication Series of Datasets; Collection
Format application/zip
Size 3 datasets
Discipline Earth System Research
Spatial Coverage (-83.730 LON, 1.227 LAT); North Pacific Ocean
Temporal Coverage Begin 1991-10-01T08:50:00Z
Temporal Coverage End 1991-11-12T04:10:00Z