(Table 2) Geochemistry at DSDP Holes 62-464 and 62-465A, supplement to: Seifert, Karl E; Vallier, Tracy L; Windom, Kenneth E; Morgan, S R (1981): Geochemistry and petrology of igneous rocks, Deep Sea Drilling Project Leg 62. In: Thiede, J; Vallier, TL; et al. (eds.), Initial Reports of the Deep Sea Drilling Project (U.S. Govt. Printing Office), 62, 945-953

DOI

Igneous rocks were recovered from three sites on Hess Rise during Deep Sea Drilling Project Leg 62: altered basalt at Site 464, at the northern end of Hess Rise; and altered trachyte from Site 465, and rounded basalt pebbles in upper Albian to middle Miocene sediments from Site 466, both at the southern end of Hess Rise. Major-, minor-, and trace-element data for basalt from Hole 464 are consistent with these rocks being transitional tholeiites that have undergone low-temperature alteration by reaction with sea water. Trachyte from Hole 465A exhibits as many as three generations of plagioclase along with potash feldspar that are flow aligned in groundmasses alterted to smectites and random mixed-layer clays. Textural evidence indicates that these rocks were eruped subaerially. Chemical data show a range of values when plotted on two- and three-component variation diagrams. The observed variations may result in part from differentiation, but they also reflect the high degree of alteration. Several oxides and elements show strong correlation with H2O+: K2O, SiO2, Rb and Lu decrease and MgO increases with increasing H2O+. These trends, except for that of Lu, are consistent with experimentally determined changes in chemistry that accompany alteration. The trend for Lu has not been previously reported; it may result from a more-intense alteration of the HREE-rich mafic minerals than of the LREE-rich feldspars. Despite their alteration, the trachytes compare favorably with alkalic differentiates from oceanic islands.

Identifier
DOI http://dx.doi.org/doi:10.1594/PANGAEA.819812
Metadata Access http://ws.pangaea.de/oai/provider?verb=GetRecord&metadataPrefix=datacite3&identifier=oai:pangaea.de:doi:10.1594/PANGAEA.819812
Provenance
Creator Seifert, Karl E;Vallier, Tracy L;Morgan, S R;Windom, Kenneth E
Publisher PANGAEA - Data Publisher for Earth & Environmental Science
Publication Year 1981
Rights Creative Commons Attribution 3.0 Unported (CC-BY)
Representation
Language English
Resource Type Supplementary Dataset
Format text/tab-separated-values
Discipline Earth System Research
Spatial Coverage (34N-40N,174E-179E)
Temporal Point 1978-08-17T11:59:59Z