10.1594/PANGAEA.751383
Ishizuka, Hideo
Hideo
Ishizuka
Chemistry of various minerals of altered basalts from ODP Hole 111-504B
PANGAEA
1989
Drilling/drill rig
Leg111
Joides Resolution
Ocean Drilling Program (ODP)
1986-10-05T11:45:00/1986-10-16T18:15:00
en
Supplementary Publication Series of Datasets
10.2973/odp.proc.sr.111.121.1989
9 datasets
application/zip
Creative Commons Attribution 3.0 Unported
Basalts recovered from Hole 504B during ODP Leg 111 are more or less altered, but there is no sign of strong shear stress or widespread penetrative deformation; hence, they retain well their primary (igneous) structures and textures. The effect of alteration is recognized as the partial or total replacement of primary minerals (olivine, clinopyroxene, and plagioclase) by secondary minerals and as the development of secondary minerals in open spaces (e.g., veins, fractures, vugs, or breccia matrix). The secondary minerals include zeolite (laumontite and stilbite), prehnite, chlorite, epidote, Plagioclase (albite and/or oligoclase), amphibole (anthophyllite, cummingtonite, actinolite, and hornblende), sodic augite, sphene, talc, anhydrite, chalcopyrite, pyrite, Fe-Ti oxide, and quartz. Selected secondary minerals from several tens of samples were analyzed by means of an electron-probe microanalyzer; the results are presented along with brief considerations of their compositional features.
In terms of the model basaltic system, the following two types of low-variance (three-phase) mineral assemblages were observed: prehnite-epidote-laumontite and prehnite-actinolite-epidote; both include chlorite, albite and/or oligoclase, sphene, and quartz. The mineral parageneses delineated by these low-variance mineral assemblages suggest that the metamorphic grade ranges from the zeolite facies to the prehnite-actinolite facies. The common occurrence of prehnite indicates that greenschist facies conditions were not attained even in the deepest level of Hole 504B, which, in a strict sense, contradicts the previous interpretation that the lower portion of Hole 504B suffered greenschist facies alteration.
Supplement to: Ishizuka, Hideo (1989): Mineral paragenesis of altered basalts from Hole 504B, ODP Leg 111. In: Becker, K; Sakai, H; et al. (eds.), Proceedings of the Ocean Drilling Program, Scientific Results, College Station, TX (Ocean Drilling Program), 111, 61-76
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1.2269000000000003
North Pacific Ocean