Identification:
Title:
Paleomagnetism of basaltic rocks cored at ODP Site 1179; implications for Mid-Cretaceous Pacific Plate paleolatitude and paleomagnetic pole
Year:
2003
Source:
In: Sager, William W., Kanazawa, Toshihiko, Escutia, Carlota, Araki, Eiichiro, Arney, James E., Carlson, Richard L., Downey, Warna S., Einaudi, Florence, Haggas, Sarah L., Hayasaka, Yasutaka, Hirata, Kenji, Horner-Johnson, Benjamin C., Mandernack, Kevin W., McCarthy, Francine M. G., Moberly, Ralph, Mochizuki, Masashi, Pedersen, Rikke Ohlenschlaeger, Salimullah, Ali R. M., Shinohara, Masanao, Werner, Carl-Dietrich, Proceedings of the Ocean Drilling Program; scientific results; Northwest Pacific Seismic Observatory and hammer drill tests; covering Leg 191 of the cruises of the drilling vessel JOIDES Resolution; Yokohama, Japan, to Apra Harbor, Guam; Sites 1179-1182; 16 July-8 September 2000
Publisher:
Texas A&M University, Ocean Drilling Program, College Station, TX, United States
Volume:
191
Issue:
Pages:
Abstract:
During Ocean Drilling Program Leg 191, approximately 100 m of mid-Cretaceous igneous crust was cored at Site 1179 (41.08 degrees N, 159.96 degrees E), located within magnetic Anomaly M8 on the abyssal plain of the northwest Pacific Ocean near Shatsky Rise. Paleomagnetic data from this section are significant because they can constrain the mid-Cretaceous Pacific plate paleolatitude and paleomagnetic pole, both of which can be used to infer tectonic drift and other geodynamic processes. In this study, we analyzed the paleomagnetism of 122 samples from 40 flows in the Site 1179 basalt section. Comparison of inclination data among flows implies 13 independent measurements of the paleomagnetic field. Assuming a reversed magnetic polarity because of the site location within Anomaly M8, the data give a mean paleocolatitude of 88.1 degrees + or -6.8 degrees (corresponding to a paleolatitude of 1.9 degrees N). The paleocolatitude is consistent with other mid-Cretaceous Pacific paleomagnetic data that indicate approximately 39 degrees northward drift of the western Pacific plate since mid-Cretaceous time. Comparison of observed between-flow colatitude variance with that expected from secular variation data suggests that secular variation may not have been completely averaged with the 13 independent groups sampled at Site 1179. Colatitude scatter in the section is markedly less in the deepest 33 m of the hole, indicating a shift from rapidly erupted flows in the bottom approximately 33 m of the section to more slowly emplaced flows above.
Language:
English
Genre:
Serial
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