Marquesas-Line Swell
Journal Article
·
· J. Geophys. Res.; (United States)
Mapping of depth anomalies in the central Pacific reveals a broad, shallow region herein termed the Marquesas--Line Swell. It has the morphology and geoid signature typical of a midplate hotspot swell and probably marks the Tertiary trace of the Marquesas hotspot. The swell is elongate in the NW--SE direction, about 800 m high, and about 1500 km wide. It appears to extend continuously between the Marquesas Islands and the Line Cross Trend. A positive geoid height anomaly over the swell can be separated from the large regional trend. The transfer function between depth anomaly and geoid height is not well defined but is consistent with local isostatic compensation with an average root depth about 30 km ( +- 40 km, 95% confidence interval) below the swell's surface. Direct spatial comparisons between geoid height and depth anomaly suggest that this root depth is constant along the length of the swell and has a value of about 40 km ( +- 10 km, 95% confidence interval). The crest of the swell appears to subside as normal seafloor which is only 25 m.y. old, the prediction of the lithospheric thinning hypothesis. A permanent density decrease within the lithosphere can also explain the subsidence and geoid height anomaly; roll-cell dynamic up-lift can explain the subsidence but is difficult to reconcile with the geoid data.
- Research Organization:
- Department of Geosciences, Purdue University, West Lafayette, Indiana 47907
- OSTI ID:
- 5671576
- Journal Information:
- J. Geophys. Res.; (United States), Journal Name: J. Geophys. Res.; (United States) Vol. 86:B12; ISSN JGREA
- Country of Publication:
- United States
- Language:
- English
Similar Records
Depth and geoid anomalies over oceanic hotspot swells: A global survey
Geoid anomalies and the thickness of the lithosphere
Analysis of geoid anomalies across the Mendocino fracture zone: implications for thermal models of the lithosphere
Journal Article
·
Mon Sep 10 00:00:00 EDT 1990
· Journal of Geophysical Research; (USA)
·
OSTI ID:6099916
Geoid anomalies and the thickness of the lithosphere
Journal Article
·
Thu May 10 00:00:00 EDT 1979
· J. Geophys. Res.; (United States)
·
OSTI ID:5984168
Analysis of geoid anomalies across the Mendocino fracture zone: implications for thermal models of the lithosphere
Journal Article
·
Wed Dec 09 23:00:00 EST 1981
· J. Geophys. Res.; (United States)
·
OSTI ID:5545697