Identifying magnetic carriers from rock magnetic characterization of Leg 183 basement cores

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doi: 10.2973/odp.proc.sr.183.005.2002
Author(s): Zhao, Xixi; Antretter, Maria J.; Solheid, Peter; Inokuchi, Hiroo
Author Affiliation(s): Primary:
University of California at Santa Cruz, Earth Sciences Department, Santa Cruz, CA, United States
Other:
University of Texas at Austin, United States
Ocean Drilling Program, United States
Ludwig-Maximilians-Universität, Federal Republic of Germany
Université de Rennes I, France
University of Rochester, United States
GEOMAR, Federal Republic of Germany
Technical University of Denmark, Denmark
University of Bristol, United Kingdom
Rheinisch-Westfälischen Technischen Hochschule Aachen, Federal Republic of Germany
Oregon State University, United States
Himeji Institute of Technology, Japan
U. S. Geological Survey, United States
Australian National University, Australia
University of Sydney, Australia
University of Notre Dame, United States
Scottish Universities Research and Reactor Centre, United Kingdom
University of Maine, United States
Bridgewater State College, United States
University of Michigan, United States
Institut für Paläontologie, Berlin, Federal Republic of Germany
Université Libre de Bruxelles, Belgium
Florida State University, United States
University of California at Santa Cruz, United States
Ludwig-Maximilians-Universität München, Federal Republic of Germany
University of Minnesota, United States
Volume Title: Proceedings of the Ocean Drilling Program; scientific results; Kerguelen Plateau-Broken Ridge; a large igneous province; covering Leg 183 of the cruises of the drilling vessel JOIDES Resolution; Fremantle, Australia, to Fremantle, Australia; Sites 1135-1142; 7 December 1998-11 February 1999
Volume Author(s): Frey, Frederick A.; Coffin, Millard F.; Wallace, Paul J.; Antretter, Maria J.; Arndt, Nicholas T.; Barling, Jane; Boehem, Florian; Borre, Mai Kirstine; Coxall, Helen K.; Damuth, John E.; Delius, Heike; Duncan, Robert A.; Inokuchi, Hiroo; Keszthelyi, Laszlo; Mahoney, John J.; Moore, C. Leah; Müller, R. Dietmar; Neal, Clive R.; Nicolaysen, Kirsten E.; Pringle, Malcolm S.; Reusch, Douglas N.; Saccocia, Peter J.; Teagle, Damon A. H.; Wähnert, Veronika; Weis, Dominique A. M.; Wise, Sherwood W.; Zhao, Xixi; Quilty, Patrick G.
Source: Proceedings of the Ocean Drilling Program; scientific results; Kerguelen Plateau-Broken Ridge; a large igneous province; covering Leg 183 of the cruises of the drilling vessel JOIDES Resolution; Fremantle, Australia, to Fremantle, Australia; Sites 1135-1142; 7 December 1998-11 February 1999, Frederick A. Frey, Millard F. Coffin, Paul J. Wallace, Maria J. Antretter, Nicholas T. Arndt, Jane Barling, Florian Boehem, Mai Kirstine Borre, Helen K. Coxall, John E. Damuth, Heike Delius, Robert A. Duncan, Hiroo Inokuchi, Laszlo Keszthelyi, John J. Mahoney, C. Leah Moore, R. Dietmar Müller, Clive R. Neal, Kirsten E. Nicolaysen, Malcolm S. Pringle, Douglas N. Reusch, Peter J. Saccocia, Damon A. H. Teagle, Veronika Wähnert, Dominique A. M. Weis, Sherwood W. Wise, Xixi Zhao and Patrick G. Quilty. Proceedings of the Ocean Drilling Program, Scientific Results (CD ROM), Vol.183, 28p. Publisher: Texas A&M University, Ocean Drilling Program, College Station, TX, United States. ISSN: 1096-2514
Note: In English. Available only on CD-ROM in PDF format and on the Web in PDF or HTML. 30 refs.CD-ROM format, ISSN 1096-2514; WWW format, ISSN 1096-7451; illus., incl. 3 tables, sketch map
Summary: In this manuscript, we present rock magnetic results of samples recovered during Leg 183. The Leg 183 cores were recovered from six drill sites and display variable rock magnetic properties. The differences in the rock magnetic properties are a function of mineralogy and alteration. Cretaceous subaerial basalt samples with titanomagnetite exhibit a strong Verwey transition in the vicinity of 110 K and have frequency-dependent susceptibility curves that resemble those of synthetic (titano) magnetites. These results are in good agreement with the thermomagnetic characteristics where titanomagnetites with Curie temperatures of ∼580°C were identified. The hysteresis ratios suggest that the bulk magnetic grain size is in the psuedo-single-domain boundary. These subaerial basalts experienced high-temperature oxidation and maintained reliable paleomagnetic records. In contrast, the 34-Ma submarine pillow basalts do not show the Verwey transition during the low-temperature experiments. Thermomagnetic analysis shows that the remanent magnetization in this group is mainly carried by a thermally unstable mineral titanomaghemite. The frequency-dependent relationships are opposite of those from the first group and show little sign of titanomagnetite characteristics. Rocks from the third group are oxidized titanomagnetites and have multiple magnetic phases. They have irreversible thermaomagnetic curves and hysteresis ratios clustering toward the multidomain region (with higher Hcr/Hc ratios). The combined investigation suggests that variations in magnetic properties correlate with changes in lithology, which results in differences in the abundance and size of magnetic minerals. The rock magnetic data on Leg 183 samples clearly indicate that titanomagnetite is the dominant mineral and the primary remanence carrier in subaerial basalt. The generally good magnetic stability and other properties exhibited by titanomagnetite-bearing rocks support the inference that the ChRM isolated from the Cretaceous sites were acquired during the Cretaceous Normal Superchron. The stable inclinations identified from these samples are therefore useful for future tectonic studies.
Year of Publication: 2003
Research Program: ODP Ocean Drilling Program
Key Words: 17 Geophysics, General; Basalts; Basement; Characterization; Cores; Cretaceous; Igneous rocks; Indian Ocean; Kerguelen Plateau; Leg 183; Magnetic hysteresis; Magnetic minerals; Magnetic properties; Mesozoic; Ocean Drilling Program; Oxides; Paleomagnetism; Southern Ocean; Thermal analysis; Thermomagnetic analysis; Titanomagnetite; Volcanic rocks
Coordinates: S600000 S320000 E0980000 E0630000
Record ID: 2006060017
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute.