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Natland, James H; Mahoney, John J (1982): Minerals, geochemistry and x-ray power characteristics at DSDP Sites 54-424, 60-458 and 60-459 [dataset publication series]. PANGAEA, https://doi.org/10.1594/PANGAEA.820231, Supplement to: Natland, JH; Mahoney, JJ (1982): Alteration of igneous rocks at Deep Sea Drilling Project Sites 458 and 459, Mariana fore-arc region: Relationship to basement structure. In: Hussong, DM; Uyeda, S; et al. (eds.), Initial Reports of the Deep Sea Drilling Project (U.S. Govt. Printing Office), 60, 769-788, https://doi.org/10.2973/dsdp.proc.60.145.1982

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Abstract:
Secondary minerals filling veins and vesicles in volcanic basement at Deep Sea Drilling Project Sites 458 and 459 indicate that there were two stages of alteration at each site: an early oxidative, probably hydrothermal, stage and a later, low-temperature, less oxidative stage, probably contemporaneous with faulting in the tectonically active Mariana forearc region. The initial stage is most evident in Hole 459B, where low-Al, high Fe smectites and iron hydroxides formed in vesicles in pillow basalts and low-Al palygorskite formed in fractures. Iron hydroxides and celadonite formed in massive basalts next to quartz-oligoclase micrographic intergrowths. Palygorskite was found in only one sample near the top of basement in Hole 458, but it too is associated with iron hydroxides. Palygorskite has previously been reported only in marine sediments in DSDP and other occurrences. It evidently formed here as a precipitate from fluids in which Si, Mg, Fe, and even some Al were concentrated. Experimental data suggest that the solutions probably had high pH and somewhat elevated temperatures. The compositions of associated smectites resemble those in hydrothermal sediments and in basalts at the Galapagos mounds geothermal field.
The second stage of alteration was large-scale replacement of basalt by dioctahedral, trioctahedral, or mixed-layer clays and phillipsite along zones of intense fracturing, especially near the bottom of Holes 458 and 459B. The basalts are commonly slickensided, and there are recemented microfault offsets in overlying sediments. Native copper occurs in one core of Hole 458, but associated smectites are dominantly dioctahedral, unlike Hole 459B, where they are mainly trioctahedral, indicating nonoxidative alteration. The alteration in both holes is more intense than at most DSDP ocean crust sites and may have been augmented by water derived from subducting ocean crust beneath the fore-arc region.
Project(s):
Deep Sea Drilling Project (DSDP)
Coverage:
Median Latitude: 14.792863 * Median Longitude: 169.741313 * South-bound Latitude: 0.593800 * West-bound Longitude: 146.934300 * North-bound Latitude: 17.864200 * East-bound Longitude: -86.130300
Date/Time Start: 1977-05-23T00:00:00 * Date/Time End: 1978-04-25T00:00:00
Event(s):
54-424 * Latitude: 0.593800 * Longitude: -86.130300 * Date/Time: 1977-05-23T00:00:00 * Elevation: -2685.0 m * Penetration: 76 m * Recovery: 36.4 m * Location: North Pacific/MOUND * Campaign: Leg54 * Basis: Glomar Challenger * Method/Device: Drilling/drill rig (DRILL) * Comment: 7 cores; 66.5 m cored; 9.5 m drilled; 54.8 % recovery
54-424B * Latitude: 0.597000 * Longitude: -86.130300 * Date/Time: 1977-05-23T00:00:00 * Elevation: -2705.0 m * Penetration: 46.5 m * Recovery: 30.3 m * Location: North Pacific/MOUND * Campaign: Leg54 * Basis: Glomar Challenger * Method/Device: Drilling/drill rig (DRILL) * Comment: 6 cores; 46.5 m cored; 0 m drilled; 65.1 % recovery
60-458 * Latitude: 17.864200 * Longitude: 146.934300 * Date/Time: 1978-04-18T00:00:00 * Elevation: -3447.0 m * Penetration: 465.5 m * Recovery: 97.6 m * Location: North Pacific/TRENCH * Campaign: Leg60 * Basis: Glomar Challenger * Method/Device: Drilling/drill rig (DRILL) * Comment: 46 cores; 437 m cored; 28.5 m drilled; 22.3 % recovery
License:
Creative Commons Attribution 3.0 Unported (CC-BY-3.0)
Size:
3 datasets

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Datasets listed in this publication series

  1. Natland, JH; Mahoney, JJ (1982): (Table 1) Sample descriptions and mineralogy at DSDP Holes 60-458 and 60-459B. https://doi.org/10.1594/PANGAEA.820227
  2. Natland, JH; Mahoney, JJ (1982): (Table 3) X-ray power characteristics for typical palygorskite samples at DSDP Hole 60-459B. https://doi.org/10.1594/PANGAEA.820230
  3. Natland, JH; Mahoney, JJ (1982): (Table 2) Geochemistry of clay minerals at DSDP Legs 60 and 54 Holes. https://doi.org/10.1594/PANGAEA.820229