@article {Petersen2009,
	title = {{Fluid seepage and mound formation offshore Costa Rica revealed by deep-towed sidescan sonar and sub-bottom profiler data}},
	journal = {Marine Geology},
	volume = {266},
	number = {1-4},
	year = {2009},
	month = {oct},
	pages = {172{\textendash}181},
	abstract = {Our analysis of geoacoustic data from the Middle American margin provides an insight into the formation and evolution mechanisms of mound structures observed on the continental slope offshore Costa Rica. Based on high-resolution deep-towed sidescan sonar and sub-bottom profiler (SBP) data six different mound and fluid seepage structures at the Hongo mound field are characterized in detail. The Hongo mound field is located on the lower continental slope offshore Nicoya peninsula in the prolongation of the subducting Nicoya fracture zone. The mounds have oval to circular shapes with diameters of 500-1600 m and relief heights of 60-100 m. High backscatter anomalies near the mound summits indicate carbonate precipitation and focused fluid seepage activity within the last 10 ka. The data do not show evidence for mud extrusions and the structures were probably formed by a combination of carbonate precipitation and mud diapirism. Based on seismic stratigraphy analysis, mud diapirism is at least active since 42.5-57 ka and average vertical growth rates vary between 6-24 cm/ka. However, if diapirism represents the dominant mound evolution mechanism, mound heights of 80 m point to much older mound ages of 330-1330 ka. {\textcopyright} 2009 Elsevier B.V. All rights reserved.},
	keywords = {carbonate, deep-towed side-scan sonar, fluid seepage, mound, mud diapir, sub-bottom profiler},
	issn = {00253227},
	doi = {10.1016/j.margeo.2009.08.004},
	url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-72049084256\&partnerID=tZOtx3y1},
	author = {Petersen, Carl J{\"o}rg and Klaucke, Ingo and Weinrebe, Wilhelm and Ranero, Cesar R.}
}
@article {Sahling2008,
	title = {{Fluid seepage at the continental margin offshore Costa Rica and southern Nicaragua}},
	journal = {Geochemistry, Geophysics, Geosystems},
	volume = {9},
	number = {5},
	year = {2008},
	month = {may},
	pages = {n/a{\textendash}n/a},
	abstract = {A systematic search for methane-rich fluid seeps at the seafloor was conducted at the Pacific continental margin offshore southern Nicaragua and northern central Costa Rica, a convergent margin characterized by subduction erosion. More than 100 fluid seeps were discovered using a combination of multibeam bathymetry, side-scan sonar imagery, TV-sled observations, and sampling. This corresponds, on average, to a seep site every 4 km along the continental slope. In the northwestern part of the study area, subduction of oceanic crust formed at the East Pacific Rise is characterized by pervasive bending-induced faulting of the oceanic plate and a relatively uniform morphology of the overriding continental margin. Seepage at this part of the margin typically occurs at approximately cone-shaped mounds 50 - 100 m high and up to 1 km wide at the base. Over 60 such mounds were identified on the 240 km long margin segment. Some normal faults also host localized seepage. In contrast, in the southeast, the 220 km long margin segment overriding the oceanic crust formed at the Cocos-Nazca Spreading Centre has a comparatively more irregular morphology caused mainly by the subduction of ridges and seamounts sitting on the oceanic plate. Over 40 seeps were located on this part of the margin. This margin segment with irregular morphology exhibits diverse seep structures. Seeps are related to landslide scars, seamountsubduction related fractures, mounds, and faults. Several backscatter anomalies in side-scan images are without apparent relief and are probably related to carbonate precipitation. Detected fluid seeps are not evenly distributed across the margin but occur in a roughly margin parallel band centered 28 {\textpm} 7 km landward of the trench. This distribution suggests that seeps are possibly fed to fluids rising from the plate boundary along deep-penetrating faults through the upper plate. Copyrignt 2008 by the American Geophysical Union.},
	keywords = {Authigenic carbonate, Chemosynthetic community, Subduction erosion},
	issn = {15252027},
	doi = {10.1029/2008GC001978},
	url = {http://www.scopus.com/inward/record.url?eid=2-s2.0-70350099584\&partnerID=tZOtx3y1},
	author = {Sahling, Heiko and Masson, Douglas G. and Ranero, Cesar R. and H{\"u}hnerbach, Veit and Weinrebe, Wilhelm and Klaucke, Ingo and B{\"u}rk, Dietmar and Br{\"u}ckmann, Warner and Suess, Erwin}
}
