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| Hekinian, Roger; Rosendahl, Bruce R.; Natland, James H.. |
| Two distinct sedimentary facies produced by sea-floor hydrothermal activity were cored during Deep Sea Drilling Project Leg 54. The first is equivalent to the typical basal iron- and manganese-rich, clayey mud recovered at many DSDP sites. It was sampled as a dispersed component throughout the cores taken in small sediment ponds in several sites within 120 km of the East Pacific Rise at 9°N. We infer that this component was originally deposited as iron hydroxides dispersed from high-temperature vents over the axial magma chamber of the East Pacific Rise. In the sediments, the iron hydroxides have reacted diagenetically with siliceous microfossil tests and detrital clays to form K- and Fe-rich clays with variable SiO(2)/Fe(2)O(3) and... |
| Tipo: Text |
Palavras-chave: Histoire Ifremer. |
| Ano: 1980 |
URL: http://archimer.ifremer.fr/doc/1980/publication-5328.pdf |
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| Natland, James H.; Rosendhal, Bruce; Hekinian, Roger; Dmitriev, Yuri; Fodor, Ronald V.; Goll, Robert M.; Hoffert, Michel; Humphris, Susan E.; Mattey, David P.; Peterson, Nikolai; Roggenthen, William; Schrader, Edward L.; Srivasiava, Ramesh K.; Warren, Nick. |
| The Galapagos mounds sea-floor hydrothermal system is at least 300,000 years old and once produced manganese-poor sediments, which nearly blanketed the area of the present mounds field. Present-day mound deposits are limited manganese-rich exposures, suggesting that the system has changed from rock- to water-dominated and has diminished in intensity with time. [NOT CONTROLLED OCR] |
| Tipo: Text |
Palavras-chave: Histoire Ifremer. |
| Ano: 1979 |
URL: http://archimer.ifremer.fr/doc/1979/publication-5382.pdf |
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| Rosendahl, Bruce R.; Hekinian, Roger; Natland, James H.; Warren, Nick; Petersen, Nikolai; Roggenthen, William; Briqueu, Louis. |
| The Pacific phase of IPOD ocean crust drilling was initiated with Leg 54, the region targeted for study by the Ocean Crust Panel being survey area PT-4 (Figure 1) (and Plate 1 [in back pocket]) north of the Siqueiros fracture zone on the western flank of the East Pacific Rise (EPR). The original purpose of this leg was to establish a type section for fast-spreading, nonrifted crust by direct sampling with stratigraphic control. We anticipated that this section would serve, in part, as a standard of comparison for other type sections, such as the Mid-Atlantic Ridge (MAR). [NOT CONTROLLED OCR] |
| Tipo: Text |
Palavras-chave: Histoire Ifremer. |
| Ano: 1980 |
URL: http://archimer.ifremer.fr/doc/1980/publication-5325.pdf |
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