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Hoernle, Kaj; Tilton, George; Schmincke, Hans-Ulrich (1991): Isotope ratios of sediments from DSDP Hole 47-397 (Table 1). PANGAEA, https://doi.org/10.1594/PANGAEA.721001, Supplement to: Hoernle, K et al. (1991): Sr-Nd-Pb isotopic evolution of Gran Canaria: evidence for shallow enriched mantle beneath the Canary Islands. Earth and Planetary Science Letters, 106(1-4), 44-63, https://doi.org/10.1016/0012-821X(91)90062-M

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Abstract:
We report the Sr, Nd and Pb isotopic compositions (1) of 66 lava flows and dikes spanning the circa 15 Myr subaerial volcanic history of Gran Canaria and (2) of five Miocene through Cretaceous sediment samples from DSDP site 397, located 100 km south of Gran Canaria. The isotope ratios of the Gran Canaria samples vary for 87Sr/86Sr: 0.70302-0.70346, for 143Nd/144Nd: 0.51275-0.51298, and for 206Pb/204Pb: 18.76-20.01. The Miocene and the Pliocene-Recent volcanics form distinct trends on isotope correlation diagrams. The most SiO2-undersaturated volcanics from each group have the least radiogenic Sr and most radiogenic Pb, whereas evolved volcanics from each group have the most radiogenic Sr and least radiogenic Pb. In the Pliocene-Recent group, the most undersaturated basalts also have the most radiogenic Nd, and the evolved volcanics have the least radiogenic Nd. The most SiO2-saturated basalts have intermediate compositions within each age group. Although the two age groups have overlapping Sr and Nd isotope ratios, the Pliocene-Recent volcanics have less radiogenic Pb than the Miocene volcanics.
At least four components are required to explain the isotope systematics of Gran Canaria by mixing. There is no evidence for crustal contamination in any of the volcanics. The most undersaturated Miocene volcanics fall within the field for the two youngest and westernmost Canary Islands in all isotope correlation diagrams and thus appear to have the most plume-like (high 238U/204Pb) HIMU-like composition. During the Pliocene-Recent epochs, the plume was located to the west of Gran Canaria. The isotopic composition of the most undersaturated Pliocene-Recent volcanics may reflect entrainment of asthenospheric material (with a depleted mantle (DM)-like composition), as plume material was transported through the upper asthenosphere to the base of the lithosphere beneath Gran Canaria. The shift in isotopic composition with increasing SiO2-saturation in the basalts and degree of differentiation for all volcanics is interpreted to reflect assimilation of enriched mantle (EM1 and EM2) in the lithosphere beneath Gran Canaria. This enriched mantle may have been derived from the continental lithospheric mantle beneath the West African Craton by thermal erosion or delamination during rifting of Pangaea. This study suggests that the enriched mantle components (EM1 and EM2) may be stored in the shallow mantle, whereas the HIMU component may have a deeper origin.
Project(s):
Coverage:
Latitude: 26.845000 * Longitude: -15.180000
Date/Time Start: 1976-03-21T00:00:00 * Date/Time End: 1976-03-21T00:00:00
Minimum Elevation: -2900.0 m * Maximum Elevation: -2900.0 m
Event(s):
47-397 * Latitude: 26.845000 * Longitude: -15.180000 * Date/Time: 1976-03-21T00:00:00 * Elevation: -2900.0 m * Penetration: 1000 m * Recovery: 587 m * Location: North Atlantic/CONT RISE * Campaign: Leg47 * Basis: Glomar Challenger * Device: Drilling/drill rig (DRILL) * Comment: 99 cores; 940 m cored; 41 m drilled; 62.4 % recovery
Parameter(s):
#NameShort NameUnitPrincipal InvestigatorMethodComment
1Sample code/labelSample labelHoernle, KajODP sample designation
2Sample commentSample commentHoernle, KajRock group
3RubidiumRbmg/kgHoernle, KajIsotope dilution
4StrontiumSrmg/kgHoernle, KajIsotope dilution
5Strontium 87/Strontium 8687Sr/86SrHoernle, Kaj
6Strontium 87/Strontium 86, error87Sr/86Sr e±Hoernle, Kaj
7SamariumSmmg/kgHoernle, KajIsotope dilution
8NeodymiumNdmg/kgHoernle, KajIsotope dilution
9Neodymium 143/Neodymium 144143Nd/144NdHoernle, Kaj
10Neodymium 143/Neodymium 144, error143Nd/144Nd e±Hoernle, Kaj
11ε-Neodymiumε-NdHoernle, Kaj
12LeadPbmg/kgHoernle, KajIsotope dilution
13UraniumUmg/kgHoernle, KajIsotope dilution
14ThoriumThmg/kgHoernle, Kaj
15Lead 206/Lead 204 ratio206Pb/204PbHoernle, Kaj
16Lead 207/Lead 204 ratio207Pb/204PbHoernle, Kaj
17Lead 208/Lead 204 ratio208Pb/204PbHoernle, Kaj
Size:
85 data points

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