thumbnail

A geochemical reconnaissance of the Alid volcanic center and geothermal system, Danakil depression, Eritrea

Geothermics

By:
, , , , , , , , ,
DOI: 10.1016/S0375-6505(99)00002-4

Links

Abstract

Geological and geochemical studies indicate that a high-temperature geothermal system underlies the Alid volcanic center in the northern Danakil depression of Eritrea. Alid is a very late-Pleistocene structural dome formed by shallow intrusion of rhyolitic magma, some of which vented as lavas and pyroclastic flows. Fumaroles and boiling pools distributed widely over an area of ~10 km2 on the northern half of Alid suggest that an active hydrothermal system underlies much of that part of the mountain. Geothermometers indicate that the fumarolic gases are derived from a geothermal system with temperatures >225??C. The isotopic composition of condensed fumarolic steam is consistent with these temperatures and implies that the source water is derived primarily from either lowland meteoric waters or fossil Red Sea water, or both. Some gases vented from the system (CO2, H2S and He) are largely magmatic in origin. Permeability beneath the volcanic center may be high, given the amount of intrusion-related deformation and the active normal faulting within the Danakil depression.Geological and geochemical studies indicate that a high-temperature geothermal system underlies the Alid volcanic center in the northern Danakil depression of Eritrea. Alid is a very late-Pleistocene structural dome formed by shallow intrusion of rhyolitic magma, some of which vented as lavas and pyroclastic flows. Fumaroles and boiling pools distributed widely over an area of approx. 10 km2 on the northern half of Alid suggest that an active hydrothermal system underlies much of that part of the mountain. Geothermometers indicate that the fumarolic gases are derived from a geothermal system with temperatures >225??C. The isotopic composition of condensed fumarolic steam is consistent with these temperatures and implies that the source water is derived primarily from either lowland meteoric waters or fossil Red Sea water, or both. Some gases vented from the system (CO2, H2S and He) are largely magmatic in origin. Permeability beneath the volcanic center may be high, given the amount of intrusion-related deformation and the active normal faulting within the Danakil depression.

Additional Publication Details

Publication type:
Article
Publication Subtype:
Journal Article
Title:
A geochemical reconnaissance of the Alid volcanic center and geothermal system, Danakil depression, Eritrea
Series title:
Geothermics
DOI:
10.1016/S0375-6505(99)00002-4
Volume
28
Issue:
2
Year Published:
1999
Language:
English
Publisher:
Elsevier Science Ltd
Publisher location:
United Kingdom
Larger Work Type:
Article
Larger Work Subtype:
Journal Article
Larger Work Title:
Geothermics
First page:
161
Last page:
187
Number of Pages:
27