The onset of fabric development in deep marine sediments

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doi: 10.1016/j.epsl.2017.06.018
Author(s): Maffione, Marco; Morris, Antony
Author Affiliation(s): Primary:
University of Birmingham, School of Geography, Earth and Environmental Sciences, Birmingham, United Kingdom
Other:
Plymouth University, United Kingdom
Volume Title: Earth and Planetary Science Letters
Source: Earth and Planetary Science Letters, Vol.474, p.32-39. Publisher: Elsevier, Amsterdam, Netherlands. ISSN: 0012-821X CODEN: EPSLA2
Note: In English. Includes appendix. 50 refs.; illus., incl. sketch map
Summary: Post-depositional compaction is a key stage in the formation of sedimentary rocks that results in porosity reduction, grain realignment and the production of sedimentary fabrics. The progressive time-depth evolution of the onset of fabric development in deep marine sediments is poorly constrained due to the limited quantity and resolution of existing data. Here we present high-resolution anisotropy of magnetic susceptibility (AMS) results from clay-rich deep marine sediments recovered at International Ocean Discovery Program Site U1438 (Philippine Sea). AMS is a petrofabric tool sensitive to the preferred orientation of grains in rocks. Down-section variations of AMS parameters, density, porosity and the inclination of magnetic remanences demonstrate that fabrics develop in response to compaction and dewatering but also that they do not develop progressively with depth below the mudline. Instead, a horizontal foliation first forms at 83 mbsf once the sediment load reaches an effective stress threshold for the onset of compaction and is then continuously enhanced down to 113 mbsf, defining a 30 m-thick 'initial compaction window'. The magnetostratigraphic age model for IODP Site U1438 indicates a delay of 5.7 Ma in initial fabric formation following sediment deposition, with strongly defined fabrics then taking an additional 6.5 Ma to develop.
Year of Publication: 2017
Research Program: IODP Integrated Ocean Drilling Program
IODP2 International Ocean Discovery Program
Key Words: 06 Petrology, Sedimentary; Cenozoic; Clay minerals; Compaction; Deep-sea environment; Expedition 351; Fabric; Foliation; IODP Site U1438; International Ocean Discovery Program; Izu-Bonin Arc; Magnetic properties; Magnetic susceptibility; Marine environment; Marine sediments; Neogene; North Pacific; Northwest Pacific; Overconsolidated materials; Pacific Ocean; Paleomagnetism; Pliocene; Porosity; Quaternary; Sedimentation; Sedimentation rates; Sediments; Sheet silicates; Silicates; Stress; Tertiary; Thickness; West Pacific
Coordinates: N272300 N272301 E1341907 E1341905
Record ID: 2017076585
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands