Petrogenesis of anomalous K-enriched MORB from the Southwest Indian Ridge: 11°53′E to 14°38′E

Roex, Anton P. le; Dick, H. J.; Watkins, Ronald T.

doi:10.1007/bf00310742

Cited by 79 publications

(58 citation statements)

References 37 publications

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“…This variability is in keeping with the generally quite variable isotopic data for individual ridge segments from the whole of the ridge (Dupre and Allegre, 1983;le Roex, et al, 1983;Hamelin and Allegre, 1985;le Roex, et al, 1985;Price, et al, 1986;Michard, et al, 1986;le Roex, et al, 1989;Mahoney, et al, 1989;le Roex, et al, 1992), but is quite a contrast to the Pb isotopic uniformity of the northern ridge segment.…”

Section: Southern Ridgesupporting

confidence: 70%

“…This is true along the entire length of the SW Indian Ridge. Away from such obvious geochemical anomalies as Marion-Prince Edward, Bouvet and the 11° East area (le Roex, et al, 1983;le Roex, et al, 1985;le Roex, et al, 1992;Kurz, et al, in press), Nd and Sr isotopic compositions on the Southwest Indian Ridge cluster around B 7Sr jB6Sr = .7028 and 143Nd/144Nd = .5130.…”

Section: Southern Ridgementioning

confidence: 99%

“…The Southwest Indian Ridge is thus one of the most slowly spreading mid-ocean ridges. The major regions of plume related magma genesis along the Southwest Indian Ridge are the Bouvet hot spot (Le Roex, et al, 1983;1985), the MarionPrince Edward hot spot and the 11 °E disturbed zone (Le Roex et al, 1992) The Atlantis II Fracture Zone (Engel and Fisher, 1975) is one of the best studied fracture zones on the Southwest Indian Ridge. It has been the object of several cruises, including a combined geophysics and petrology cruise (R/V Robert Conrad 27-09: and an ocean drilling leg ( ODP Leg 118, von Herzen, Robinson, et al, 1991).…”

Section: Geology Of the Atlantis II Fracture Zonementioning

confidence: 99%

“…The one aragonite Sr isotopic composition measured for this study is too similar to modem seawater in its isotopic composition to be the age of the crust that sample came from (maximum 24 Ma). That crustal age, however, is subject to significant uncertainty since the tectonics of the 12°-14°E area that the sample came from are extremely complex and have not been studied in great detail Qe Roex, et al, 1992).…”

Section: Seawatermentioning

confidence: 99%

“…12° E Area Figure 17 shows basalts from the 12-14°E region (le Roex, et al, 1992) plotted with the one peridotite clinopyroxene analyzed from that region. The samples enclosed by the light stipple are from the entire 12-l4°E region, while the ones enclosed by the dark stipple are from the same dredge haul (Dredge 6) as the peridotite sample.…”

Section: Comparison Of Prlmary Peridotite Isotopic Compositions Withmentioning

confidence: 99%

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The isotope geochemistry of abyssal peridotites and related rocks

Snow¹

1993

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Section: Southern Ridgesupporting

confidence: 70%

Section: Southern Ridgementioning

confidence: 99%

Section: Geology Of the Atlantis II Fracture Zonementioning

confidence: 99%

Section: Seawatermentioning

confidence: 99%

Section: Comparison Of Prlmary Peridotite Isotopic Compositions Withmentioning

confidence: 99%

See 3 more Smart Citations

The isotope geochemistry of abyssal peridotites and related rocks

Snow¹

1993

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Isotope and trace element insights into heterogeneity of subridge mantle

Mallick

Dick

Sachi-Kocher

et al. 2014

Geochem Geophys Geosyst

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Geochemical data for abyssal peridotites are used to determine the relationship to mid-ocean ridge basalts from several locations at ridge segments on the SW Indian Ridge (SWIR), the Mid-Cayman-Rise (MCR), and the Mid-Atlantic Ridge (MAR). Based on chemical and petrological criteria peridotites are categorized as being either dominantly impregnated with melt or being residual after recent melting. Those that are considered impregnated with melt also have isotopic compositions similar to the basalts indicating impregnation by an aggregate MORB melt. A SWIR and MCR residual peridotite Nd-isotopic compositions partly overlap the Nd-isotopic compositions of the basalts but extend to more radiogenic compositions. The differences between peridotite and basalt Nd-isotopic compositions can be explained by incorporating a low-solidus component with enriched isotopic signature in the subridge mantle: a component that is preferentially sampled by the basalts. At the MAR, peridotites and associated basalts have overlapping Ndisotopic compositions, suggesting a more homogeneous MORB mantle. The combined chemistry and petrography indicates a complex history with several depletion and enrichment events. The MCR data indicate that a low-solidus component can be a ubiquitous component of the asthenosphere. Residual abyssal peridotites from limited geographic areas also show significant chemical variations that could be associated with initial mantle heterogeneities related to events predating the ridge-melting event. Sm-Nd model ages for possible earlier depletion events suggest these could be as old as 2.4 Ga.

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Postseafloor Spreading Volcanism in the Central East South China Sea and Its Formation Through an Extremely Thin Oceanic Crust

Zhao

Sibuet

et al. 2018

Geochem Geophys Geosyst

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P wave velocity models were obtained by forward and inverse modeling from 38 ocean bottom seismometers deployed in the central East subbasin of the South China Sea (SCS). Four types of crust have been defined: (a) thin oceanic crust (<5 km), (b) typical oceanic crust (5–6 km), (c) thick oceanic crust hosting postspreading volcanoes (>6 km) with significant intrusive roots, and (d) thick oceanic crust with enhanced spreading features (>6 km) but without significant roots. Within the central East subbasin, the thin oceanic crust, only identified inside an 80 km wide zone, is located within an overall 150 km wide domain characterized by N055° seafloor spreading trends. The postspreading volcanoes were formed during a N‐S tensional episode around 6–10 Ma, several millions of years after seafloor spreading ceased in the SCS. Seafloor spreading (N055° and N145°) and postspreading (N000° and N090°) features are observed in the morphology of some of these volcanoes. The rupture of the brittle thin oceanic crust was focused where the crust was the weakest, i.e., at the intersection of the extinct spreading ridge with former fracture zones. From geological and geophysical arguments, we suggest that the postspreading volcanism might have been influenced by the Hainan plume activity through a buoyancy‐driven partial melting mechanism.

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Petrogenesis of anomalous K-enriched MORB from the Southwest Indian Ridge: 11°53′E to 14°38′E

Cited by 79 publications

References 37 publications

The isotope geochemistry of abyssal peridotites and related rocks

The isotope geochemistry of abyssal peridotites and related rocks

Isotope and trace element insights into heterogeneity of subridge mantle

Postseafloor Spreading Volcanism in the Central East South China Sea and Its Formation Through an Extremely Thin Oceanic Crust

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