40Ar-39Ar plateau and isochron ages from the Ninetyeast and Broken Ridges (Table 1)

Concordant plateau and isochron ages are obtained from 40Ar-39Ar incremental heating experiments on volcanic rocks recovered by drilling at three Leg 121 sites along the Ninetyeast Ridge and two dredge locations on the southern scarp of the Broken Ridge, eastern Indian Ocean. The new data confirm a...

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Bibliographic Details
Main Author: Duncan, Robert A
Format: Dataset
Language:English
Published: PANGAEA 1991
Subjects:
121-756D
121-757C
121-758A
Age
dated
dated standard deviation
Argon-39
Argon-40/Argon-36
standard deviation
DRILL
Drilling/drill rig
DSDP/ODP/IODP sample designation
Event label
Indian Ocean
Joides Resolution
Leg121
Ocean Drilling Program
ODP
Parameter
Sample amount
Sample code/label
South Indian Ridge
South Indian Ocean
Broken Ridge
Indian
Kerguelen
Kerguelen Islands
Online Access:https://doi.pangaea.de/10.1594/PANGAEA.761131
https://doi.org/10.1594/PANGAEA.761131
Description
Summary:Concordant plateau and isochron ages are obtained from 40Ar-39Ar incremental heating experiments on volcanic rocks recovered by drilling at three Leg 121 sites along the Ninetyeast Ridge and two dredge locations on the southern scarp of the Broken Ridge, eastern Indian Ocean. The new data confirm a northerly increase in the age of volcanism along the Ninetyeast Ridge, from 38 to 82 Ma; this lineament links current hotspot volcanism near the Kerguelen islands with the Rajmahal flood basalt eruptions at M0 time (117 ± 1 Ma). The Broken Ridge was formed over the same hotspot at 88-89 Ma, but later experienced rift-related volcanism in Paleocene time (63 Ma). The geometry and distribution of ages along these prominent volcanic ridges and the Mascarene-Chagos-Laccadive-Maldive ridge system in the western Indian Ocean are most compatible with plate motions over fixed hotspots near Kerguelen and Reunion islands, respectively.

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