East Pacific rise at 21°N: the volcanic, tectonic, and hydrothermal processes of the central axis
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Abstract
Photographs obtained by the ANGUS survey system at 21°N reveal many similarities to the geological processes delineated at other spreading centers and in particular those observed in the Galapagos Rift at 86°W. The region of recent volcanism is restricted to a narrow zone (Zone 1) approximately 1 km wide. This suggests that the width of the magma chamber feeding these flows is also narrow at the top. Variations in sediment cover are used to subdivide the flows within Zone 1 into three sheet-flow/pillow-flow pairs. The youngest pair appears to have erupted form a linear fissure 8 km long running parallel to the valley axis. This fissure is part of a larger en echelon pattern of eruptive fissures. Active hydrothermal vents associated with the youngest flows are situated directly above the apparent eruptive fissure. The high (350°C) temperature for some of the fluids exiting from the vents suggests a highly restricted circulation system involving, at times, little to no mixing with cold seawater. The lava terrain in the remainder of Zone 1 and bordering regions is characterized by extensive fracturing, further suggesting a narrow upper dimension to the magma chamber and also that subsurface hydrothermal deposition of massive sulfides may lead to a reduction in the mixing processes.
| Publication type | Article |
|---|---|
| Publication Subtype | Journal Article |
| Title | East Pacific rise at 21°N: the volcanic, tectonic, and hydrothermal processes of the central axis |
| Series title | Earth and Planetary Science Letters |
| DOI | 10.1016/0012-821X(81)90081-9 |
| Volume | 55 |
| Issue | 1 |
| Year Published | 1981 |
| Language | English |
| Publisher | Elsevier |
| Contributing office(s) | Coastal and Marine Geology Program |
| Description | 10 p. |
| First page | 1 |
| Last page | 10 |
| Online Only (Y/N) | N |
| Additional Online Files (Y/N) | N |