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

Earth and Planetary Science Letters
By: , and 



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
Online Only (Y/N) N
Additional Online Files (Y/N) N
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