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| Format: | Dataset Open Access |
| Language: | en |
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PANGAEA
1992
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| Online Access: | https://doi.org/10.1594/PANGAEA.774205 |
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| _version_ | 1867169041664180224 |
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| author | Egeberg, Per Kristian Brunfelt, Arild O Stabel, Arne S |
| author_facet | Egeberg, Per Kristian Brunfelt, Arild O Stabel, Arne S |
| collection | Datos científicos de ciencias marinas y ambientales |
| contents | Glass shards from 26 megascopic tephras (1-29 cm thick) were separated and analyzed for 26 elements and 87Sr/86Sr and 143Nd/144Nd isotope ratios. The isotope data allowed us to assess the degree of alteration of the samples. The separates contain less than 10% of palagonitized glass or secondary alteration minerals. Correlation diagrams and multivariate analyses have been used to characterize the glass shards in a tectonic setting and group the tephras according to their magmatic affinity. Four tholeiitic groups, two calc-alkaline groups, and one group with glass of shoshonitic affinity can be distinguished. The tholeiitic groups form a time series; however, judging from the rare-earth-element patterns and the temporal variations of the Ce/Yb ratios, the evolution is not unidirectional from strong to weak tholeiitic affinity. The tephras have been correlated with volcanism along the Izu-Ogasawara and Ryukyu arcs by means of trace element distribution, 87Sr/86Sr ratios, and their magmatic affinity. The tholeiitic layers were derived from volcanoes on the Izu-Ogasawara Arc, most probably from the volcanic island Hachijojima. Only one group of the calc-alkaline layers can have derived from the Izu-Ogasawara Arc. The other calc-alkaline layers and the two layers with shoshonitic affinity probably derive from volcanism along the Ryukyu Arc. |
| format | Dataset Open Access |
| id | pangaea_https___doi_org_10_1594_PANGAEA_774205 |
| institution | PANGAEA |
| language | en |
| publishDate | 1992 |
| publisher | PANGAEA |
| record_format | pangaea |
| spellingShingle | (Table 1) Composition of selected ash layers in ODP Site 126-792 Egeberg, Per Kristian Brunfelt, Arild O Stabel, Arne S 126-792A; 126-792E; AGE; Antimony; Barium; Caesium; Cerium; Cobalt; DEPTH, sediment/rock; DRILL; Drilling/drill rig; DSDP/ODP/IODP sample designation; Europium; Event label; Hafnium; Holmium; Instrumental neutron activation analysis (INAA) (Reimann et al., 1998); Iron oxide, Fe2O3; Isotope dilution; Joides Resolution; Lanthanum; Layer description; Layer thickness; Leg126; Lutetium; Neodymium; Neodymium-143/Neodymium-144 ratio; North Pacific Ocean; Ocean Drilling Program; ODP; Rubidium; Samarium; Sample code/label; Selenium; Sodium oxide; Strontium; Strontium-87/Strontium-86 ratio; Tantalum; Terbium; Thorium; Thulium; Titanium dioxide; Tungsten; Uranium; Ytterbium; Zirconium Glass shards from 26 megascopic tephras (1-29 cm thick) were separated and analyzed for 26 elements and 87Sr/86Sr and 143Nd/144Nd isotope ratios. The isotope data allowed us to assess the degree of alteration of the samples. The separates contain less than 10% of palagonitized glass or secondary alteration minerals. Correlation diagrams and multivariate analyses have been used to characterize the glass shards in a tectonic setting and group the tephras according to their magmatic affinity. Four tholeiitic groups, two calc-alkaline groups, and one group with glass of shoshonitic affinity can be distinguished. The tholeiitic groups form a time series; however, judging from the rare-earth-element patterns and the temporal variations of the Ce/Yb ratios, the evolution is not unidirectional from strong to weak tholeiitic affinity. The tephras have been correlated with volcanism along the Izu-Ogasawara and Ryukyu arcs by means of trace element distribution, 87Sr/86Sr ratios, and their magmatic affinity. The tholeiitic layers were derived from volcanoes on the Izu-Ogasawara Arc, most probably from the volcanic island Hachijojima. Only one group of the calc-alkaline layers can have derived from the Izu-Ogasawara Arc. The other calc-alkaline layers and the two layers with shoshonitic affinity probably derive from volcanism along the Ryukyu Arc. |
| title | (Table 1) Composition of selected ash layers in ODP Site 126-792 |
| topic | 126-792A; 126-792E; AGE; Antimony; Barium; Caesium; Cerium; Cobalt; DEPTH, sediment/rock; DRILL; Drilling/drill rig; DSDP/ODP/IODP sample designation; Europium; Event label; Hafnium; Holmium; Instrumental neutron activation analysis (INAA) (Reimann et al., 1998); Iron oxide, Fe2O3; Isotope dilution; Joides Resolution; Lanthanum; Layer description; Layer thickness; Leg126; Lutetium; Neodymium; Neodymium-143/Neodymium-144 ratio; North Pacific Ocean; Ocean Drilling Program; ODP; Rubidium; Samarium; Sample code/label; Selenium; Sodium oxide; Strontium; Strontium-87/Strontium-86 ratio; Tantalum; Terbium; Thorium; Thulium; Titanium dioxide; Tungsten; Uranium; Ytterbium; Zirconium |
| url | https://doi.org/10.1594/PANGAEA.774205 |