Magnetic properties of sediments from Ocean Drilling Program sites 1109, 1115, and 1118 (Leg 180), Woodlark Basin (Papua New Guinea)

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doi: 10.1186/BF03352436
Author(s): Ishikawa, Naoto; Frost, Gina Marie
Author Affiliation(s): Primary:
Kyoto University, Graduate School of Human and Environmental Studies, Kyoto, Japan
Central Oregon Community College, United States
Volume Title: Earth, Planets and Space
Source: Earth, Planets and Space, 54(9), p.883-897. Publisher: Terra Scientific Publishing Company (TERRAPUB), Tokyo, Japan. ISSN: 1343-8832
Note: In English. 20 refs.; illus., incl. sects., sketch map
Summary: Latest Miocene-Pleistocene synrift sediments at Ocean Drilling Program sites 1109, 1115, and 1118 (Leg 180), located on the hanging wall margin north of the Moresby fault in the Woodlark Basin, showed variations in magnetic parameters carried by magnetite and maghemite related to sedimentation process in the basin. At sites 1109 and 1115, an increase in the sedimentation rate at 3.8 Ma was accompanied by the deposition of sediments with low ferromagnetic mineral concentrations. An increase in the ferrimagnetic mineral concentrations occurred between 3.4 Ma and 3.2 Ma at the three sites. The onset age of the change became younger with distance from the subsidence center of the basin near the Moresby fault: 3.4 Ma at Site 1118, 3.3 Ma at Site 1109, and 3.2 Ma at Site 1115, which implies a northward onlapping of sediments with high ferrimagnetic mineral concentration. Sediments with finer-grained ferrimagnetic minerals were deposited between 2.3 and 2.0 Ma at sites 1118 and 1109 and later, 2.8 Ma at Site 1115 during a period of a low sedimentation rate. The upper parts of sites 1109 and 1115 had a diamagnetic contribution, which is attributed to relatively high concentrations of diamagnetic pelagic materials at a low sedimentation rate associated with the low frequency of turbidites.
Year of Publication: 2002
Research Program: ODP Ocean Drilling Program
Key Words: 03 Geochronology; 06 Petrology, Sedimentary; Australasia; Cenozoic; Geochronology; Leg 180; Maghemite; Magnetic properties; Magnetite; Magnetization; Marine sediments; Miocene; Natural remanent magnetization; Neogene; ODP Site 1109; Ocean Drilling Program; Oxides; Paleomagnetism; Papua; Papua New Guinea; Pelagic sedimentation; Pleistocene; Quaternary; Remanent magnetization; Sedimentation; Sedimentation rates; Sediments; Tertiary; Upper Miocene; Woodlark Basin
Coordinates: S093024 S093024 E1513423 E1513423
Record ID: 2003036911
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