Skip to Main Content
Skip Nav Destination

Ninetyeast Ridge (Indian Ocean); a 5000 km record of a Dupal mantle plume

D. Weis, F. A. Frey, A. Saunders, I. L. Gibson, Jonathan Dehn, Neal Driscoll, John Farrell, Elisabeth Fourtanier, Paul D. Gamson, Jeffrey S. Gee, Thomas Janacek, Chris Klootwijk, James R. Lawrence, Ralf Littke, Jerry S. Newman, Ritsuo Nomura, Robert M. Owen, John Peirce, James J. Popsichal, David K. Rea, Purtyasti Resiwati, Jan Smit, Guy M. Smith, Kensaku Tamaki, Elliott Taylor, Jeffrey K. Weissel and Craig Wilkinson
Ninetyeast Ridge (Indian Ocean); a 5000 km record of a Dupal mantle plume
Geology (Boulder) (February 1991) 19 (2): 99-102


Data and observation from Drifting Program Leg 121 and plate-tectonic reconstructions indicate that the Ninetyeast Ridge (Indian Ocean) was derived from the interaction of a deep-seated Dupal hotspot and a nearby spreading-ridge axis. The 5000-km-long ridge, from lat 34 degrees S to Rat 10 degrees N, was drilled at three sites during Leg 121. About 178 m of basalt, >38 to >80 Ma, were recovered from a total penetration of approximately 310 m. Shipboard petrographic and geochemical studies showed that each site has distinctive characteristics. Most of the cored lavas have a tholeiitic basalt composition. Incompatible-element abundanes and ratios show systematic trends, consistent with an origin for the Ninetyeast Ridge lavas by mixing between a depleted component-Indian Ocean mid-ocean ridge basalt-and an enriched component-oceanic-island basalt similar to that observed in the youngest alkalic basalts from the Kerguelen archipelago. Preliminary shore-based trace element abundance and isotopic data are compatible with this hypothesis, although Pb isotopes indicate the involvement of another component.The long-lasting and more or less continuous activity of the Kerguelen-Heard plume (ca. 115 Ma), now located under Heard Island, south of the Southeast Indian Ridge, provides evidence that the source of the Dupal anomaly is deep seated.

ISSN: 0091-7613
EISSN: 1943-2682
Serial Title: Geology (Boulder)
Serial Volume: 19
Serial Issue: 2
Title: Ninetyeast Ridge (Indian Ocean); a 5000 km record of a Dupal mantle plume
Affiliation: Univ. Libre Bruxelles, Lab. Assoc. Geol.-Petrol.-Geochronol., Brussels, Belgium
Affiliation: Ocean Drilling Program, Leg 121, Shipboard Scientific Party
Pages: 99-102
Published: 199102
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 46
Accession Number: 1991-011326
Categories: Geochemistry of rocks, soils, and sedimentsIgneous and metamorphic petrologySolid-earth geophysics
Document Type: Serial
Bibliographic Level: Analytic
Illustration Description: illus. incl. 1 table, sketch map
S35°00'00" - N08°00'00", E85°00'00" - E92°00'00"
Secondary Affiliation: Mass. Inst. Technol., USA, United StatesUniv. Leicester, GBR, United KingdomUniv. Waterloo, CAN, CanadaRuhr Univ., DEU, Federal Republic of GermanyLamont Doherty Geol. Obs., USA, United StatesBrown Univ., USA, United StatesEc. Norm. Super., FRA, FranceScripps Inst. Oceanogr., USA, United StatesAust. Bur. Miner. Resour., AUS, AustraliaUniv. Houston, USA, United StatesNucl. Res. Cent., DEU, Federal Republic of GermanyGECO Geophys. Co., USA, United StatesShimane Univ., JPN, JapanUniv. Mich., USA, United StatesPetro Canada, CAN, CanadaFla. State Univ., USA, United StatesUniv. Nebr., USA, United StatesFree Univ., NLD, NetherlandsSt. Louis Univ., USA, United StatesUniv. Tokyo, JPN, Japan
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute.
Update Code: 1991
Program Name: ODPOcean Drilling Program
Close Modal

or Create an Account

Close Modal
Close Modal