caa a22 4500 463216393 CHVBK 20180405153157.0 cr unu---uuuuu 170326e20070601xx s 000 0 eng 10.1007/s00367-007-0063-5 doi (NATIONALLICENCE)springer-10.1007/s00367-007-0063-5 Stratigraphic framework of gas accumulations in the Ría de Pontevedra (NW Spain) [Elektronische Daten] [Ruth Durán, Soledad García-Gil, Raquel Diez, Federico Vilas] Knowledge of marine geological environments in which shallow gas is accumulating is becoming increasingly important in global studies of climate change because a measurable proportion of the total methane source comes from continental margins. Previous studies have revealed that coastal environments represent important geological environments where microbial methane is being generated, is accumulating, and is being released. In the Ría de Pontevedra, at least 4.5km2 of seafloor in the innermost part of the ría is underlain by sediments containing natural gas. Seismic interpretation contributes new findings for the definition of periods and geological environments in which the gas could have been generated, and is accumulating and released in the Ría de Pontevedra. Groundtruthing the seismic data (facies, environments) makes it possible to identify favourable geological environments for gas generation in the sedimentary infill of the Ría de Pontevedra. Sequence stratigraphy based on high-resolution seismic profiles and post-Last Glacial Maximum sea-level records makes it possible to establish the stratigraphic architecture of the ría and to define the periods in which gas could have been generated. The results of this study show that the sedimentary infill is composed of a fifth-order sequence developed since the Last Glacial Maximum. Within this sequence, gas appears to have accumulated in the Holocene deposits associated with the latest transgressive and highstand system tracts. Seismic analysis shows that gas could have been generated in different geological environments in the Ría de Pontevedra. If coastal environments at times of lower sea level were similar to those of the present, organic-rich mud deposits (deposited mainly in lakes, estuaries and floodplains) could have survived transgression and remained buried as potential gas sources in the inner part of the ría. Springer-Verlag, 2007 Durán Ruth Dpt. Geociencias Marinas, Fac. Ciencias del Mar, Universidad de Vigo, 36310, Vigo, Spain aut García-Gil Soledad Dpt. Geociencias Marinas, Fac. Ciencias del Mar, Universidad de Vigo, 36310, Vigo, Spain aut Diez Raquel Dpt. Geociencias Marinas, Fac. Ciencias del Mar, Universidad de Vigo, 36310, Vigo, Spain aut Vilas Federico Dpt. Geociencias Marinas, Fac. Ciencias del Mar, Universidad de Vigo, 36310, Vigo, Spain aut Geo-Marine Letters Springer-Verlag 27/2-4(2007-06-01), 77-88 0276-0460 27:2-4<77 2007 27 367 https://doi.org/10.1007/s00367-007-0063-5 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/s00367-007-0063-5 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Durán Ruth Dpt. Geociencias Marinas, Fac. Ciencias del Mar, Universidad de Vigo, 36310, Vigo, Spain aut NATIONALLICENCE 700 1- García-Gil Soledad Dpt. Geociencias Marinas, Fac. Ciencias del Mar, Universidad de Vigo, 36310, Vigo, Spain aut NATIONALLICENCE 700 1- Diez Raquel Dpt. Geociencias Marinas, Fac. Ciencias del Mar, Universidad de Vigo, 36310, Vigo, Spain aut NATIONALLICENCE 700 1- Vilas Federico Dpt. Geociencias Marinas, Fac. Ciencias del Mar, Universidad de Vigo, 36310, Vigo, Spain aut NATIONALLICENCE 773 0- Geo-Marine Letters Springer-Verlag 27/2-4(2007-06-01), 77-88 0276-0460 27:2-4<77 2007 27 367 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer