Chemical composition and elemental oxide ratios to AI2O3 of bulk solids at DSDP Leg 64 Holes
Fuente:
PANGAEA
Salvato in:
| Autore principale: | |
|---|---|
| Natura: | Dataset Open Access |
| Lingua: | en |
| Pubblicazione: |
PANGAEA
1982
|
| Soggetti: | |
| Accesso online: | |
| Tags: |
Aggiungi Tag
Nessun Tag, puoi essere il primo ad aggiungerne!!
|
| _version_ | 1867169509853364224 |
|---|---|
| author | Niemitz, Jeffrey W |
| author_facet | Niemitz, Jeffrey W |
| collection | Datos científicos de ciencias marinas y ambientales |
| contents | Analyses of sediments from Leg 64 sites reveal a diverse and in one case unique geochemistry. Sites are characterized by high heat flow along an active, divergent plate boundary, or rapid accumulation of diatom muds, or both. The geochemical trends of Sites 474-476 at the tip of Baja California reflect changes4n the percentages of sedimentary components - particularly biogenous matter and mineralogy - that support interpretations of sedimentary environments inferred to be present since the commencement of subsidence along this young, passive continental margin. The sediments below dolerite sills in Holes 477, 477A, 478, and 481 show major mineralogic and chemical deviations from "average" hemipelagic sediments. The sills appear to have two functions: (1) they allow hydrothermal circulation and metamorphism in a partially closed system by trapping heat and fluids emanating from below, and (2) they expel heated interstitial fluids at the moment of intrusion and mobilize elements, most likely leading to the formation of metalliferous deposits along the surface traces of normal faults in the basin. The hydrothermal system as a whole appears to be localized and ephemeral, as is indicated by the lack of similar geochemical trends and high heat flow at Sites 478 and 481. Site 479 illustrates sedimentation in an oxygen-minimum zone with anoxic sediments and concomitant geochemical trends, especially for MnO. With few exceptions, geochemical trends are remarkably constant with depth, suggesting that Site 479 can serve as an "internal" standard or average sediment against which the magnitude of hydrothermal alteration at the basinal Sites 477, 478, and 481 can be measured. |
| format | Dataset Open Access |
| id | pangaea_https___doi_org_10_1594_PANGAEA_818551 |
| institution | PANGAEA |
| language | en |
| publishDate | 1982 |
| publisher | PANGAEA |
| record_format | pangaea |
| spellingShingle | Chemical composition and elemental oxide ratios to AI2O3 of bulk solids at DSDP Leg 64 Holes Niemitz, Jeffrey W 64-474; 64-474A; 64-475; 64-476; 64-477; 64-477A; 64-478; 64-479; 64-481; 64-481A; Deep Sea Drilling Project; DRILL; Drilling/drill rig; DSDP; Glomar Challenger; Leg64; North Pacific/Gulf of California/BASIN; North Pacific/Gulf of California/CHANNEL; North Pacific/Gulf of California/SLOPE; North Pacific/Gulf of California/TERRACE Analyses of sediments from Leg 64 sites reveal a diverse and in one case unique geochemistry. Sites are characterized by high heat flow along an active, divergent plate boundary, or rapid accumulation of diatom muds, or both. The geochemical trends of Sites 474-476 at the tip of Baja California reflect changes4n the percentages of sedimentary components - particularly biogenous matter and mineralogy - that support interpretations of sedimentary environments inferred to be present since the commencement of subsidence along this young, passive continental margin. The sediments below dolerite sills in Holes 477, 477A, 478, and 481 show major mineralogic and chemical deviations from "average" hemipelagic sediments. The sills appear to have two functions: (1) they allow hydrothermal circulation and metamorphism in a partially closed system by trapping heat and fluids emanating from below, and (2) they expel heated interstitial fluids at the moment of intrusion and mobilize elements, most likely leading to the formation of metalliferous deposits along the surface traces of normal faults in the basin. The hydrothermal system as a whole appears to be localized and ephemeral, as is indicated by the lack of similar geochemical trends and high heat flow at Sites 478 and 481. Site 479 illustrates sedimentation in an oxygen-minimum zone with anoxic sediments and concomitant geochemical trends, especially for MnO. With few exceptions, geochemical trends are remarkably constant with depth, suggesting that Site 479 can serve as an "internal" standard or average sediment against which the magnitude of hydrothermal alteration at the basinal Sites 477, 478, and 481 can be measured. |
| title | Chemical composition and elemental oxide ratios to AI2O3 of bulk solids at DSDP Leg 64 Holes |
| topic | 64-474; 64-474A; 64-475; 64-476; 64-477; 64-477A; 64-478; 64-479; 64-481; 64-481A; Deep Sea Drilling Project; DRILL; Drilling/drill rig; DSDP; Glomar Challenger; Leg64; North Pacific/Gulf of California/BASIN; North Pacific/Gulf of California/CHANNEL; North Pacific/Gulf of California/SLOPE; North Pacific/Gulf of California/TERRACE |
| url | https://doi.org/10.1594/PANGAEA.818551 |