Gas hydrate versus seabed morphology offshore Lebu (Chilean margin)

Iván Vargas-Cordero, Umberta Tinivella, Lucía Villar-Muñoz, Joaquim P. Bento, Carolina Cárcamo, Diego López-Acevedo, Francisco Fernandoy, Alessandra Rivero, Marion San Juan

Research output: Contribution to journalArticlepeer-review

6 Citations (Scopus)

Abstract

Gas-hydrate occurrences along the Chilean margin have been widely documented, but the processes associated with fluid escapes caused by the dissociation of gas hydrates are still unknown. We report a seabed morphology growth related to fluid migration offshore Lebu associated with mud cones by analysing oxygen and deuterium stable water isotopes in pore water, bathymetric, biological and sedimentological data. A relief was observed at - 127 m water depth with five peaks. Enrichment values of δ18O (0.0-1.8‰) and δD (0.0-5.6‰) evidenced past hydrate melting. The orientation of the relief could be associated with faults and fractures, which constitute pathways for fluid migration. The benthic foraminifera observed can be associated with cold seep areas. We model that the mud cones correspond to mud growing processes related to past gas-hydrate dissociation. The integration of (i) the seismic data analysis performed in the surrounding area, (ii) the orientation of our studied relief, (iii) the infaunal foraminifera observed, (iv) the grain size and (v) the total organic matter and isotope values revealed that this area was formerly characterised by the presence of gas hydrates. Hence, this part of the Chilean margin represents a suitable area for investigating fluid-migration processes.

Original languageEnglish
Article number21928
Pages (from-to)21928
Number of pages1
JournalScientific Reports
Volume10
Issue number1
DOIs
Publication statusPublished - 14 Dec 2020

ASJC Scopus subject areas

  • General

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