Conspicuous deepwater submarine mounds in the northeastern Orphan Basin and on the Orphan Knoll, offshore Newfoundland

Enachescu, Michael E.

doi:10.1190/1.1843371

Cited by 7 publications

(7 citation statements)

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“…Cold water coral reefs composed primarily of Lophelia have been well documented at 40e350 m depths offshore Norway (Hovland and Thomsen, 1997) and have frequently been associated with seafloor seepage sites at several locations (Hovland and Risk, 2003;Enachescu, 2004).…”

Section: Discussionmentioning

confidence: 99%

Old marine seismic and new satellite radar data: Petroleum exploration of north west Labrador Sea, Canada

Jauer

Budkewitsch²

2010

Marine and Petroleum Geology

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Section: Discussionmentioning

confidence: 99%

Old marine seismic and new satellite radar data: Petroleum exploration of north west Labrador Sea, Canada

Jauer

Budkewitsch²

2010

Marine and Petroleum Geology

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“…The lack of the 'Christmas tree' profile could indicate that the feature is the result of only one or two mud eruptions, but this contrasts with the multiple seismic horizons within the structure, suggestive of several episodes of deposition. Enachescu (2004) noted that salt intrusions are usually opaque internally and show undulating walls, unlike the Houtman seamounts. In addition, there is no known evaporitic sequence associated with the Perth Basin from which salt intrusions could be sourced, although the Early Jurassic Eneabba Formation 'redbeds' may contain some evaporitic material, albeit in very low volume.…”

Section: Mud Volcanismmentioning

confidence: 96%

Enigmatic seafloor structures in the Perth Basin (Houtman Sub-basin), offshore Western Australia: deep-water carbonate mounds or volcanic cones?

Gorter¹

2009

Australian Journal of Earth Sciences

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“…Enachescu (2004) reported more than 200 large mounds hundreds of meters wide and maybe hundreds of meters high in deep-water in the Orphan Basin, offshore Newfoundland in the NW Atlantic, that might be bioherms or modern coral colonies related to water bottom hydrothermal vents, but no samples or pictures have ever been obtained. His conclusions are from indirect evidence and seismic interpretation.…”

Section: Discussionmentioning

confidence: 99%

“…They are concerned for many reasons but generally they want to better understand the ecology so they can catch fi sh in a more ecological fashion but also so that the fi shery does not get shut down. Closing ecologically unique areas to fi shing has been proposed by Enachescu (2004), specifi cally for the Orphan Knoll, off Newfoundland. This possibility should encourage further research by fi shery, wildlife, and oceanography offi cials into the study area with the idea in mind of visiting the site with cameras and samplers.…”

Section: Discussionmentioning

confidence: 99%

Carbonate blocks found in muddy sediment off Cape Breton Island, Nova Scotia: pieces of small authigenic carbonate mounds and vents related to hydrocarbon seeps?

Wallace

Harrington

Cook

2006

atgeol

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Carbonate blocks brought up from the seafl oor during drag fi shing in a small restricted area offshore northern Cape Breton Island are irregularly shaped and range in size from 6 cm 3 to >1 m 3 . They have smooth to "clinkery", dendritic, or "popcorn-surface" structures, can be layered to massive, and are porous. Many are highly porous and/or eroded. They contain fi ne-grained siliciclastic material (mud to granule sized) with minor amounts of bioclasts cemented by calcite. Three blocks have vent structures and some have pores lined by fi ne-grained sparite. Seismic lines in the vicinity of the discovery area show acoustic turbidity, bright spots interpreted to be hydrocarbon seeps, diaper-like structures, and columnar sediment disturbances that reach to bedrock. Outside the immediate area, pock marks occur on the sediment surface. Carbon isotope values from shelly material cemented in the blocks range from δ 13 13 C = -9.41 to -35.27 ‰ PDB (Pee Dee Belemnite) with an algae encrustation or bacterial mat yielding -61.38 ‰ PDB. From the isotopic analysis and the seismic interpretation we are confi dent that these blocks are pieces of carbonate mounds and vents formed by methanogenesis of hydrocarbon from slow seeps on the seafl oor, the hydrocarbon originating either within the recent sediment and/or from bedrock, most likely the latter. The ecology of these mounds has not been studied and needs further work in this area of active commercial fi shing. RÉSUMÉLes blocs de roches carbonatées repêchées du fond de la mer par des chalutiers dans un petit secteur à accès restreint au large, au nord de l'île du Cap-Breton, sont d'apparence irrégulière et leur taille varie entre 6 cm 3 et plus de 1 m 3 . Ils sont de texture lisse à « scoriacée », sont de nature dendritique et présentent une surface de « maïs éclaté »; les blocs peuvent être stratifi és ou d'apparence massive, et ils sont poreux. Un bon nombre des blocs sont très poreux ou érodés, ou les deux. Ils contiennent du matériau silicoclastique à grain fi n (entre la boue et les granules), ainsi que de petites quantités de bioclastes à cimentation calcitique. Trois blocs présentent une structure à orifi ces, tandis que d'autres ont des pores recouverts de sparite à grain fi n. Le profi l sismique dans les environs de la découverte indiquent une turbidité acoustique, et présentent des zones claires dont l'interprétation donne à penser qu'il s'agit de suintements d'hydrocarbures, à structure stratiforme, ainsi que des perturbations de sédiments prismatiques qui atteignent le substratum rocheux. À une certaine distance de la découverte, on note des marques de rigoles sur la surface sédimentaire. Les valeurs des isotopes de carbone tirées des matières coquillières cimentées dans les blocs varient entre δ 13 13 C = -9.41 et -35.27 ‰ PDB (bélemnites de la formation Pee Dee), et s'accompagnent d'une incrustation algale ou d'une matte bactérienne d'une valeur de -61.38 ‰ PDB. À la lumière de l'analyse isotopique et de l'interprétation sismique, nous sommes relativ...

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Conspicuous deepwater submarine mounds in the northeastern Orphan Basin and on the Orphan Knoll, offshore Newfoundland

Cited by 7 publications

References 0 publications

Old marine seismic and new satellite radar data: Petroleum exploration of north west Labrador Sea, Canada

Old marine seismic and new satellite radar data: Petroleum exploration of north west Labrador Sea, Canada

Enigmatic seafloor structures in the Perth Basin (Houtman Sub-basin), offshore Western Australia: deep-water carbonate mounds or volcanic cones?

Carbonate blocks found in muddy sediment off Cape Breton Island, Nova Scotia: pieces of small authigenic carbonate mounds and vents related to hydrocarbon seeps?

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