Lower Jaramillo polarity transition records from ODP Holes 108-665A and 121-758B


Autoria(s): Gee, Jeff S; Tauxe, Lisa; Barg, Eunjoo
Cobertura

MEDIAN LATITUDE: 4.167600 * MEDIAN LONGITUDE: 35.346700 * SOUTH-BOUND LATITUDE: 2.951200 * WEST-BOUND LONGITUDE: -19.667800 * NORTH-BOUND LATITUDE: 5.384000 * EAST-BOUND LONGITUDE: 90.361200 * DATE/TIME START: 1986-04-03T21:00:00 * DATE/TIME END: 1988-06-15T15:58:00

Data(s)

26/05/1991

Resumo

Two records of the geomagnetic polarity transition at the beginning of the Jaramillo Subchron (0.97 Ma) have been obtained from sediments in the equatorial Atlantic (Leg 108, Site 665; 2.95°N, 340.33°E) and Indian (Leg 121, Site 758; 5.38°N, 90.35°E) oceans. Both cores yielded high-quality magnetostratigraphic results; however, the relatively low sedimentation rates, the weak magnetizations, and complex demagnetization behavior of some transitional samples suggest that the record of the transitional field behavior may be less reliable. In addition, variations in grain size preclude reliable paleointensity determinations although the remanence in both cores is apparently dominated by magnetite. Despite these possible complications, the two cores yield transitional paths that are neither far-sided nor near-sided. Together with published records that meet minimum reliability standards, the two equatorial records presented here suggest that the lower Jaramillo transitional field morphology was significantly nonaxisymmetric. The mean normal and reversed inclinations from both cores deviate from the inclination expected from a geocentric axial dipole, as noted in virtually all marine sediment cores. The observed inclinations provide further support for a polarity-dependent nondipole contribution to the time-averaged field.

Formato

application/zip, 2 datasets

Identificador

https://doi.pangaea.de/10.1594/PANGAEA.761128

doi:10.1594/PANGAEA.761128

Idioma(s)

en

Publicador

PANGAEA

Direitos

CC-BY: Creative Commons Attribution 3.0 Unported

Access constraints: unrestricted

Fonte

Supplement to: Gee, Jeff S; Tauxe, Lisa; Barg, Eunjoo (1991): Lower Jaramillo polarity transition records from the equatorial Atlantic and Indian Oceans. In: Weissel, J; Peirce, J; Taylor, E; et al. (eds.), Proceedings of the Ocean Drilling Program, Scientific Results, College Station, TX (Ocean Drilling Program), 121, 377-391, doi:10.2973/odp.proc.sr.121.152.1991

Palavras-Chave #108-665A; 121-758B; Decl (AF); DRILL; Drilling/drill rig; Indian Ocean; Inten (AF); Joides Resolution; Label; Leg108; Leg121; MAD; Maximum angular deviation; N; No; North Atlantic Ocean; NRM, Declination after demagnetisation; NRM, Intensity after demagnetization; Number; Ocean Drilling Program; ODP; ODP sample designation; range (mT); Sample amount; Sample code/label; Treatm; Treatment; with origin; without origin
Tipo

Dataset