Evidence for hydrothermal venting and sediment volcanism discharged after recent short-lived volcanic eruptions at Deception Island, Bransfield Strait, Antarctica
- 作者：Somoza ; L. ; Martí ; nez-Frí ; as ; J. ; Smellie ; J.L. ; Rey ; J. ; Maestro ; A.
- 关键词：hydrothermal vents ; submarine volcanoes ; geophysical surveys ; geochemical investigations ; Antarctica
- 刊名：Marine Geology
- 出版年：2004
- 期刊代码：57_00253227
- 类别：ear
- 出版时间：January 15, 2004
- 卷：203
- 期：1-2
- 页码：119-140
- 文件大小：1.68 M
摘要
The results of a combined geophysical and geochemical research programme on Deception Island, an active volcano at 62°43′S, 60°57′W in Bransfield Strait (Antarctica), are presented. Ultrahigh-resolution acoustic data obtained with a TOPAS (TOpographic PArameter Sonar) system and multibeam bathymetry (Simrad EM1000) allow a detailed analysis of submarine vents in Port Foster, the submerged caldera of Deception Island. The data show three different types of seafloor structures: low-relief mounds, high-relief mounds (‘wasp nest’-like) and spire-like structures. We interpret these structures as products of sediment volcanism and seeps caused by heating and boiling of pore fluids in gas-charged sediments, and related to recent short-lived volcanic events, possibly those that occurred in 1967, 1969 and 1970. In addition, subsurface vertical disturbed zones, formed by increased amplitude and phase-inverse reflectors beneath the mounds, suggest the presence of fluidised and brecciated sediments within hydrofracture systems. A key finding of this study is that there appears to be a close relationship between the submarine mounds detected by our ultrahigh-resolution seismic study, geochemical haloes, fault-pathways and present-day thermal anomalies in surface waters. We suggest that seafloor hydrofracture systems and subsurface pipes can be re-used as fluid migration pathways, resulting in hydrothermal seeps and vents on the seafloor, possibly up to decades after coeval volcanic eruptions.