Hydrothermal input in recent sediments proximal to the eastern lau spreading centre, lau basin, sw pacific
The partition geochemistry and recent Mn accumulation rates have been studied in 14 sediment corescollected adjacent to the Eastern Lau Spreading Centre (ELSC) in the Lau Basin, SW Pacific. Thesediments are oxic in nature, formed of ash with abundant nannofossil ooze and hydrothermal Mn oxidesdisper...
| Autores: | , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2001 |
| País: | México |
| Institución: | Universidad Autónoma de Baja California |
| Repositorio: | Redalyc-UABC |
| OAI Identifier: | oai:redalyc.org:48027409 |
| Acceso en línea: | https://www.redalyc.org/articulo.oa?id=48027409 |
| Access Level: | acceso abierto |
| Palabra clave: | Ciencias de la Tierra sediment Lau Basin geochemistry hydrothermal manganese accumulation |
| Sumario: | The partition geochemistry and recent Mn accumulation rates have been studied in 14 sediment corescollected adjacent to the Eastern Lau Spreading Centre (ELSC) in the Lau Basin, SW Pacific. Thesediments are oxic in nature, formed of ash with abundant nannofossil ooze and hydrothermal Mn oxidesdispersed within the calcareous sediments. These oxides represent distal plume fallout derived mainlyfrom the hydrothermal fields along the ELSC and possibly from the nearby Central Lau Spreading Centre(CLSC). Nickel, Mo, Pb and, to a lesser extent, Co and V are associated with the Mn-oxide phase,possibly scavenged by Mn precipitates. Only low proportions of Fe, Zn and Cu are found in the oxidephase, these elements being mainly associated with the detrital/altered-detrital sediment phases. Somepeaks in the Mn distribution downcore appear to correlate among the cores studied, indicating commonpulses of hydrothermal plume fallout. The similar Fe/Mn oxide ratios (1.41.9) in surficial sedimentsproximal to the Eastern and Central Lau Spreading Centres, suggest similar plume fallout compositionsin these two areas. Mean Mn accumulation rates average 26 mg cm2 ka1. The hydrothermalsedimentation near the ELSC is probably related to a fully developed hydrothermal plumbing at thespreading centre and thus the ELSC has a good potential for hosting massive sulphide deposits, althougha lower hydrothermal input at its northernmost tip may indicate a drop in magmatic activity and mineralpotential in the oldest section of this spreading ridge. |
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