Please use this identifier to cite or link to this item: http://hdl.handle.net/2122/6196
AuthorsEtiope, G.* 
Klusman, R. W.* 
TitleMicroseepage in drylands: Flux and implications in the global atmospheric source/sink budget of methane
Issue Date2010
Series/Report no./72 (2010)
DOI10.1016/j.gloplacha.2010.01.002
URIhttp://hdl.handle.net/2122/6196
Keywordsmicroseepage
methane flux
soil sink
drylands
petroleum
greenhouse gas
Subject Classification04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry 
AbstractDrylands are considered a net sink for atmospheric methane and a main item of the global inventories of the greenhouse gas budget. It is outlined here, however, that a significant portion of drylands occur over sedimentary basins hosting natural gas and oil reservoirs, where gas migration to the surface takes place, producing positive fluxes of methane into the atmosphere. New field surveys, in different hydrocarbonprone basins, confirm that microseepage, enhanced by faults and fractures in the rocks, overcomes the methanotrophic consumption occurring in dry soil throughout large areas, especially in the winter season. Fluxes of a few units to some tens of mg m−2 day−1 are frequent over oil–gas fields, whose global extent is estimated at 3.5–4.2 million km2; higher fluxes (>50 mg m−2 day−1) are primarily, but not exclusively, found in basins characterized by macro-seeps. Microseepage may however potentially exist over a wider area (∼8 million km2, i.e. 15% of global drylands), including the Total Petroleum Systems, coal measures and portions of sedimentary basins that have experienced thermogenesis. Based on a relatively large and geographically dispersed data-set (563 measurements) from different hydrocarbon-prone basins in USA and Europe, upscaling suggests that global microseepage emission exceeding 10 Tg year−1 is very likely. Microseepage is then only one component of a wider class of geological sources, including mud volcanoes, seeps, geothermal and marine seepage, which cannot be ignored in the atmospheric methane budget.
Appears in Collections:Papers Published / Papers in press

Files in This Item:
File Description SizeFormat 
Article.pdf1.77 MBAdobe PDFView/Open    Request a copy
Show full item record

Page view(s)

92
checked on Apr 26, 2017

Download(s)

42
checked on Apr 26, 2017

Google ScholarTM

Check

Altmetric