TY - JOUR
T1 - Hallazgo del primer seep fósil en la costa emergida de Chile central (33°56' S). Caracterización e implicancias
AU - Contardo-Berríos, Ximena
AU - Mena-Hodges, Emilio
AU - Quiroga, Eduardo
N1 - Funding Information:
Esta investigaci?n fue parcialmente financiada por un proyecto D.I. iniciaci?n 2011, de la PUCV: ?Determinaci?n e implicancias del promisorio hallazgo de un potencial paleoseep de metano, en la zona costera de la localidad de Navidad? (037306/2011). Se destacan las observaciones y aportes en terreno de la Dra. K. Campbell, de la Universidad de Auckland, Nueva Zelanda, especialista en cold seeps y del Dr. S. Nielsen, de la Universidad Austral de Valdivia, Chile, que contribuyeron al desarrollo exitoso de este estudio. Se agradece al grupo de estudiantes de oceanograf?a de la PUCV que participaron y motivaron la realizaci?n de la primera excursi?n a terreno donde se realiz? el hallazgo.
Publisher Copyright:
© 2017, Servicio Nacional de Geologia y Mineria. All rights reserved.
PY - 2017
Y1 - 2017
N2 - This study presents the main characteristics of the first fossil hydrocarbon seep documented on the emerged coast of Central Chile. The Navidad Paleoseep (NPS) is an outcrop of carbonate and fossil organisms preserved on the beach of the Navidad locality. The carbonate structure is oriented N45° W, perpendicular to the coastline and discordant with sub horizontal Miocene sequences found in the area. This type of authigenic carbonate accumulation, originates on the sea floor as the result of anaerobic oxidation of methane, generated by low temperature fluids released through seafloor fractures. The NPS consists mainly of calcium carbonate in the form of matrix and crystallized precipitate. Based on textural features, dominant facies of the outcrop were defined as mudstone and wackestone. The associated mineralogy consists of magnesian calcite, predominantly as micrite matrix, minor components of quartz, albite, amphibole, orthoclase, microcline and fragments of volcanic lithics are also identified. The NPS also contains a variety of fossils, such as bivalves, gastropods, tube worms, teredolites, microbialites and others. The occurrence of Lucinoma promaucana in the paleoseep, evidences a temporal and spatial correlation with the Navidad Formation i.e., would ranges from lower to middle Miocene. The δ13C values vary between -41.4‰ in the matrix and -29.5‰ PDB in bivalve shells, representing the typical negative δ13C values seen in hydrocarbon seeps.
AB - This study presents the main characteristics of the first fossil hydrocarbon seep documented on the emerged coast of Central Chile. The Navidad Paleoseep (NPS) is an outcrop of carbonate and fossil organisms preserved on the beach of the Navidad locality. The carbonate structure is oriented N45° W, perpendicular to the coastline and discordant with sub horizontal Miocene sequences found in the area. This type of authigenic carbonate accumulation, originates on the sea floor as the result of anaerobic oxidation of methane, generated by low temperature fluids released through seafloor fractures. The NPS consists mainly of calcium carbonate in the form of matrix and crystallized precipitate. Based on textural features, dominant facies of the outcrop were defined as mudstone and wackestone. The associated mineralogy consists of magnesian calcite, predominantly as micrite matrix, minor components of quartz, albite, amphibole, orthoclase, microcline and fragments of volcanic lithics are also identified. The NPS also contains a variety of fossils, such as bivalves, gastropods, tube worms, teredolites, microbialites and others. The occurrence of Lucinoma promaucana in the paleoseep, evidences a temporal and spatial correlation with the Navidad Formation i.e., would ranges from lower to middle Miocene. The δ13C values vary between -41.4‰ in the matrix and -29.5‰ PDB in bivalve shells, representing the typical negative δ13C values seen in hydrocarbon seeps.
KW - Authigenic carbonate
KW - Chemosynthesis
KW - Hydrocarbon
KW - Lucinoma promaucana
KW - Navidad formation
KW - Paleoseep
KW - Tectonic
UR - http://www.scopus.com/inward/record.url?scp=85023620003&partnerID=8YFLogxK
U2 - 10.5027/andgeoV44n2-a05
DO - 10.5027/andgeoV44n2-a05
M3 - Article
AN - SCOPUS:85023620003
VL - 44
SP - 213
EP - 228
JO - Andean Geology
JF - Andean Geology
SN - 0718-7092
IS - 2
ER -