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East Pacific rise at 21°N: the volcanic, tectonic, and hydrothermal processes of the central axis

Earth and Planetary Science Letters

By:
, , , , and
DOI: 10.1016/0012-821X(81)90081-9

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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.

Additional Publication Details

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
Number of Pages:
10
Online Only (Y/N):
N
Additional Online Files(Y/N):
N