Amsterdam Island, an isolated volcano in the southern Indian ocean

Gunn, Bernard M.; Abranson, Christian E.; Nougier, J.; Watkins, N. D.; Hajash, Andrew

doi:10.1007/bf00383052

Cited by 25 publications

(8 citation statements)

References 6 publications

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“…Hot spot volcanism of the ASP Plateau initiated less than 5 million years ago on the basis of the age of seafloor surrounding the plateau [ Scheirer et al , 2000]. Subaerial lavas from Amsterdam are less than 0.7 Ma [ Gunn et al , 1971] although the most recent paleomagnetic and argon geochronology suggests ages of 26 ± 15 and 18 ± 9 kyr [ Carvallo et al , 2003]. The breached caldera of St. Paul is morphologically young and is most likely less than 0.5 Ma [ Watkins et al , 1974].…”

Section: Geologic Settingmentioning

confidence: 99%

Influence of the Amsterdam/St. Paul hot spot along the Southeast Indian Ridge between 77° and 88°E: Correlations of Sr, Nd, Pb, and He isotopic variations with ridge segmentation

Nicolaysen

Frey

Mahoney

et al. 2007

Geochem Geophys Geosyst

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[1] The submarine Amsterdam-St. Paul (ASP) Plateau, bisected by the Southeast Indian Ridge (SEIR), is a bathymetric high rising $2 km above the surrounding seafloor that includes the islands of Amsterdam and St. Paul; this excess volcanism is attributed to a mantle hot spot. We obtained new Sr, Nd, and Pb (n = 37) and He isotopic (n = 10) ratios for basalt glasses from 11 SEIR segments on and adjacent to the plateau and from three seamounts on the plateau. The results show systematic spatial variations in these isotopic ratios that correlate with physical segmentation of the ridge. Specifically, lavas from the four ridge segments on the ASP Plateau have higher 208 Pb/ 204 Pb at a given 206 Pb/ 204 Pb than SEIR basalts distant from ASP Plateau. Surprisingly, lavas from the ridge segment 100 km north of the ASP Plateau are distinguished by the most radiogenic 206 Pb/ 204 Pb (up to 19.4) and highest 3 He/ 4 He ratios (up to 14

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Section: Geologic Settingmentioning

confidence: 99%

Influence of the Amsterdam/St. Paul hot spot along the Southeast Indian Ridge between 77° and 88°E: Correlations of Sr, Nd, Pb, and He isotopic variations with ridge segmentation

Nicolaysen

Frey

Mahoney

et al. 2007

Geochem Geophys Geosyst

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“…Thus located in the immediate vicinity of a mid‐ocean ridge, lava from Amsterdam has mainly a tholeiitic geochemical composition, ranging from olivine tholeiite to plagioclase basalt. From a structural point of view, this volcanic island corresponds to a double strato‐volcano (Gunn et al 1971). The first cycle of activity is represented by a volcano centred on the southern part of the island, where Mount du Fernand and Le Pinion correspond to remnants of a volcanic caldera (Fig.…”

Section: Geological Setting and Palaeomagnetic Samplingmentioning

confidence: 99%

Mono Lake or Laschamp geomagnetic event recorded from lava flows in Amsterdam Island (southeastern Indian Ocean)

Carvallo

Camps

Ruffet

et al. 2003

Geophysical Journal International

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We report a survey carried out on basalt flows from Amsterdam Island in order to check the presence of intermediate directions interpreted to belong to a geomagnetic field excursion within the Brunhes epoch, completing this paleomagnetic record with paleointensity determinations and radiometric dating. The directional results corroborate the findings by Watkins and Nougier (1973) : normal polarity is found for two units and an intermediate direction, with associated VGPs close to the equator, for the other two units. A notable result is that these volcanic rocks are well suited for absolute paleointensity determinations. Fifty percent of the samples yields reliable intensity values with high quality factors. An original element of this study is that we made use of the PTRM-tail test of Shcherbakova et al. (2000) to help in the interpretation of the paleointensity measurements. Doing thus, only the high temperature intervals, beyond 400 degres C, were retained to obtain the most reliable estimate of the strength of the ancient magnetic field. The normal units yield Virtual Dipole Moments (VDM) of 6.2 and 7.7 10e22 Am2 and the excursional units yield values of 3.7 and 3.4 10e22 Am2. These results are quite consistent with the other Thellier determinations from Brunhes excursion records, all characterized by a decrease of the VDM as VGP latitude decreases. 40Ar/39Ar isotopic age determinations provide an estimate of 26+-15 Kyr and 18+-9 Kyr for the transitional lava flows, which could correspond to the Mono Lake excursion. However, the large error bars associated with these ages do not exclude the hypothesis that this event is the Laschamp

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“…The enrichment of the seamounts is particularly striking in K 2 O with contents higher than 1.5% and reaching 2.2%. On the plateau, the maximum K 2 O concentration reaches 1.3% for one sample from the current SEIR but the published values typically range between 0.1% and 1% [ Girod et al , 1971; Gunn et al , 1971, 1975; Doucet et al , 2004].…”

Section: Major Elementsmentioning

confidence: 87%

“…Those islands have been the object of early studies [ von Hochstetter , 1866; Velain , 1878; Reinisch , 1909]. In the 1970s, Gunn et al [1971], Watkins and Nougier [1973], Watkins et al [1974], Hedge et al [1973], and Watkins et al [1975] provided an extensive geological study of the islands and revealed that they were globally less that 0.7 Ma old for Amsterdam and 0.4 Ma old for St. Paul. In addition, recent paleomagnetic and Ar geochronology on the most recent lava flows have produced much younger ages of 26 +/− 15 ka and 18 +/− 9 ka for Amsterdam Island [ Carvallo et al , 2003].…”

Section: Geological Settingsmentioning

confidence: 99%

The Amsterdam–St. Paul Plateau: A complex hot spot/DUPAL‐flavored MORB interaction

Janin

Hémond

Maia

et al. 2012

Geochem Geophys Geosyst

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[1] The Amsterdam-St Paul (ASP) oceanic plateau results from the interaction between the ASP hot spot and the Southeast Indian ridge. A volcanic chain, named the Chain of the Dead Poets (CDP), lies to its northward tip and is related to the hot spot intraplate activity. The ASP plateau and CDP study reveals that ASP plume composition is inherited from oceanic crust and pelagic sediments recycled in the mantle through a 1.5 Ga subduction process. The ASP plateau lavas have a composition (major and trace elements and Sr-Nd-Pb-Hf isotopes) reflecting the interaction between ASP plume and the Indian MORB mantle, including some clear DUPAL input. The Indian upper mantle below ASP plateau is heterogeneous and made of a depleted mantle with lower continental crust (LCC) fragments probably delaminated during the Gondwana break-up. The lower continental crust is one of the possible reservoirs for the DUPAL anomaly origin that our data support. The range of magnitude of each end-member required in ASP plateau samples is (1) 45% to 75% of ASP plume and (2) 25% to 55% of Indian DM within 0% to a maximum of 6% of LCC layers included within. The three end-members involved (plume, upper mantle and lower continental crust) and their mixing in different proportions enhances the geochemical variability in the plateau lavas. Consequently, the apparent composition homogeneity of Amsterdam Island, an aerial summit of the plateau, may result from the presence of intermediate magmatic chambers into the plateau structure.

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Amsterdam Island, an isolated volcano in the southern Indian ocean

Cited by 25 publications

References 6 publications

Influence of the Amsterdam/St. Paul hot spot along the Southeast Indian Ridge between 77° and 88°E: Correlations of Sr, Nd, Pb, and He isotopic variations with ridge segmentation

Influence of the Amsterdam/St. Paul hot spot along the Southeast Indian Ridge between 77° and 88°E: Correlations of Sr, Nd, Pb, and He isotopic variations with ridge segmentation

Mono Lake or Laschamp geomagnetic event recorded from lava flows in Amsterdam Island (southeastern Indian Ocean)

The Amsterdam–St. Paul Plateau: A complex hot spot/DUPAL‐flavored MORB interaction

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