Blog
About

11
views
0
recommends
+1 Recommend
1 collections
    0
    shares
      • Record: found
      • Abstract: found
      • Article: found
      Is Open Access

      Data report: microstructure of chilled margins in the sheeted dike complex of IODP Hole 1256D: Expedition 309/312

      , ,

      Proceedings of the IODP

      Integrated Ocean Drilling Program

      Read this article at

      ScienceOpenPublisher
      Bookmark
          There is no author summary for this article yet. Authors can add summaries to their articles on ScienceOpen to make them more accessible to a non-specialist audience.

          Abstract

          Chilled margins were recovered from the sheeted dike complex (SDC) of superfast (>200 mm/y)-spreading East Pacific Rise–spread crust during drilling of Integrated Ocean Drilling Program Hole 1256D on the Cocos Plate. The chilled margins contain stretched spherules, oriented plagioclase laths, grain-size segregation, and color banding. These rheomorphs locally crosscut veins but are elsewhere crosscut by veins. Electron microprobe investigations found that the chilled margins comprise dispersed micrometer-scale minerals and veins including chlorite, actinolite, quartz, anhydrite, sphene, calcite, sphalerite, K-feldspar (adularia and/or orthoclase), magnetite, pyrite, and chalcopyrite. Though many of these phases are present throughout the SDC, anhydrite and calcite have not been previously recognized >100 m below the SDC–lava transition zone, and, with one exception, K-feldspar has not been previously identified in Hole 1256D core. Microstructures include quartz clasts surrounded by anhydrite, K-feldspar veins and clasts cut or surrounded by chilled margin material, and lenses of ductily deformed sphene. Some of the crosscutting relationships and distribution of mineral phases could be explained by hydrothermal alteration that occurred roughly simultaneously with dike intrusion.

          Related collections

          Most cited references 13

          • Record: found
          • Abstract: not found
          • Book: not found

          The operated Markov´s chains in economy (discrete chains of Markov with the income)

            Bookmark
            • Record: found
            • Abstract: found
            • Article: not found

            Drilling to gabbro in intact ocean crust.

            Sampling an intact sequence of oceanic crust through lavas, dikes, and gabbros is necessary to advance the understanding of the formation and evolution of crust formed at mid-ocean ridges, but it has been an elusive goal of scientific ocean drilling for decades. Recent drilling in the eastern Pacific Ocean in Hole 1256D reached gabbro within seismic layer 2, 1157 meters into crust formed at a superfast spreading rate. The gabbros are the crystallized melt lenses that formed beneath a mid-ocean ridge. The depth at which gabbro was reached confirms predictions extrapolated from seismic experiments at modern mid-ocean ridges: Melt lenses occur at shallower depths at faster spreading rates. The gabbros intrude metamorphosed sheeted dikes and have compositions similar to the overlying lavas, precluding formation of the cumulate lower oceanic crust from melt lenses so far penetrated by Hole 1256D.
              Bookmark
              • Record: found
              • Abstract: not found
              • Article: not found

              Quartz-cemented breccias from the Mid-Atlantic Ridge: Samples of a high-salinity hydrothermal upflow zone

                Bookmark

                Author and article information

                Journal
                10.2204/iodp.proc.309312.2006
                Proceedings of the IODP
                Integrated Ocean Drilling Program
                1930-1014
                09 July 2009
                Article
                10.2204/iodp.proc.309312.205.2009

                This work is licensed under a Creative Commons Attribution 4.0 Unported License. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/

                Product
                Self URI (journal page): http://publications.iodp.org/

                Comments

                Comment on this article