Hydrocarbon gases in Tertiary and Quaternary sediments offshore Peru


Autoria(s): Kvenvolden, Keith A; Frank, Tamara J; Golan-Bac, Margaret
Cobertura

MEDIAN LATITUDE: 25.609118 * MEDIAN LONGITUDE: -51.902014 * SOUTH-BOUND LATITUDE: -13.480160 * WEST-BOUND LONGITUDE: -90.800000 * NORTH-BOUND LATITUDE: 66.678300 * EAST-BOUND LONGITUDE: 4.576700 * DATE/TIME START: 1980-10-13T00:00:00 * DATE/TIME END: 1986-12-18T09:00:00

Data(s)

16/11/1990

Resumo

Hydrocarbon gases (methane, ethane, propane, isobutane, n-butane, ethene, and propene) are present in Tertiary and Quaternary shelf, upper-slope, and lower-slope deposits of the Peruvian continental margin. Methane dominates the composition of the hydrocarbon gas at all 10 sites examined during Ocean Drilling Program (ODP) Leg 112. Generation of methane is regulated by the amount of sulfate in pore water. Wherever sulfate concentrations approach or equal zero, methane concentrations increase rapidly, reaching values near 100,000 µL/L of wet sediment at eight of the 10 sites. Methane at all 10 sites results from methanogenesis, which is inhibited where sulfate is present and microbial reduction of sulfate occurs. Hydrocarbon gases heavier than methane also are present, but at much lower concentrations than methane. These hydrocarbons are thought to result from early thermal and microbial diagenesis, based on relative gas compositions and trends of concentrations with depth. With few exceptions, the results obtained in the shipboard and shore-based laboratories are comparable for methane and ethane in sediments of Leg 112. Reanalyses of canned sediments from ODP Leg 104 and from Deep Sea Drilling Project (DSDP) Legs 76 and 84 show that gas samples can be stored for as long as 8 yr, but the amounts of individual hydrocarbon gases retained vary. Nevertheless, the trends of the data sets with depth are similar for fresh and stored samples.

Formato

application/zip, 3 datasets

Identificador

https://doi.pangaea.de/10.1594/PANGAEA.753682

doi:10.1594/PANGAEA.753682

Idioma(s)

en

Publicador

PANGAEA

Direitos

CC-BY: Creative Commons Attribution 3.0 Unported

Access constraints: unrestricted

Fonte

Supplement to: Kvenvolden, Keith A; Frank, Tamara J; Golan-Bac, Margaret (1990): Hydrocarbon gases in Tertiary and Quaternary sediments offshore Peru - results and comparisons. In: Suess, E; von HuenE; R; et al. (eds.), Proceedings of the Ocean Drilling Program, Scientific Results, College Station, TX (Ocean Drilling Program), 112, 505-515, doi:10.2973/odp.proc.sr.112.146.1990

Palavras-Chave #104-644A; 112-679; 112-680B; 112-681B; 112-681C; 112-682A; 112-683A; 112-683B; 112-684C; 112-685A; 112-686B; 112-687B; 112-688A; 112-688E; 76-533; 76-533A; 84-565; 84-568; Butane; C2H6; C3H8; CH4; COMPCORE; Composite Core; Deep Sea Drilling Project; Depth; DEPTH, sediment/rock; DRILL; Drilling/drill rig; DSDP; Ethane; Event; Glomar Challenger; i-C4H10; Isobutane; Joides Resolution; Leg104; Leg112; Leg76; Leg84; Methane; n-C4; North Atlantic/RIDGE; North Pacific/SLOPE; North Pacific/TRENCH; Norwegian Sea; Ocean Drilling Program; ODP; ODP sample designation; Propane; Sample code/label; South Pacific Ocean; USGS; USGS, C3:1
Tipo

Dataset