CaltechAUTHORS
  A Caltech Library Service

Variations in ridge morphology and depth-age relationships on the Pacific-Antarctic Ridge

Marks, Karen M. and Stock, Joann M. (1994) Variations in ridge morphology and depth-age relationships on the Pacific-Antarctic Ridge. Journal of Geophysical Research B, 99 (B1). pp. 531-541. ISSN 0148-0227. https://resolver.caltech.edu/CaltechAUTHORS:20141010-100018449

[img]
Preview
PDF - Published Version
See Usage Policy.

1224Kb
[img]
Preview
PDF - Erratum
See Usage Policy.

34Kb

Use this Persistent URL to link to this item: https://resolver.caltech.edu/CaltechAUTHORS:20141010-100018449

Abstract

Adjacent segments of the Pacific-Antarctic ridge display significantly different morphologies and depth-age relationships over seafloor younger than 36 Ma. The spreading corridor southwest of Fracture Zone XII is characterized by a rift valley and an usually small subsidence constant of 226±13 m/m.y.^(½), while the two spreading corridors immediately northeast of Fracture Zone XII have an axial high and a subsidence constant consistent with the global average. This abrupt variation in ridge morphology is not usually characteristic of medium-rate spreading centers, nor is such an abrupt variation expected of adjacent ridge segments that are spreading at the same rate. We suggest that a thermal anomaly beneath the ridge may influence the first-order effects of spreading rate and lithospheric cooling enough to produce the observed rift valley and axial high and the different subsidence constants. Although we are not certain what would produce the thermal anomaly here, we speculate that when the spreading rate on the Pacific-Antarctic ridge increased from slow to intermediate rates since 20 Ma, so did the need for materials for accretion, which may be supplied in part by along-axis asthenospheric flow from hotspots or a hot region to the northeast. A sufficient supply of hot asthenosphere may still be lacking in the ridge segment with the axial valley to the southwest, leaving it cooler and starved for accretionary materials.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1029/93JB02760 DOIArticle
http://onlinelibrary.wiley.com/doi/10.1029/93JB02760/abstractPublisherArticle
http://dx.doi.org/10.1029/94JB01686 ErrataCorrection
ORCID:
AuthorORCID
Stock, Joann M.0000-0003-4816-7865
Additional Information:© 1994 by the American Geophysical Union. Paper number 93JB02760. Received July 23, 1992; revised August 11, 1993; accepted September 28, 1993. We wish to thank Dennis Hayes and an anonymous reviewer and associate editor whose suggestions led to improvements in this manuscript. Discussions with Walter Smith were also helpful. J. Stock's participation was supported by NSF grant EAR-9058217.
Group:Seismological Laboratory
Funders:
Funding AgencyGrant Number
NSFEAR-9058217
Issue or Number:B1
Record Number:CaltechAUTHORS:20141010-100018449
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:20141010-100018449
Official Citation:Marks, K. M., and J. M. Stock (1994), Variations in ridge morphology and depth-age relationships on the Pacific-Antarctic Ridge, J. Geophys. Res., 99(B1), 531–541, doi:10.1029/93JB02760
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:50335
Collection:CaltechAUTHORS
Deposited By: Tony Diaz
Deposited On:10 Oct 2014 18:41
Last Modified:03 Oct 2019 07:22

Repository Staff Only: item control page