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TitleUpdated lithological, biostratigraphic, and thermal alteration data for the lLower Paleozoic, offshore Labrador, Canada
AuthorBingham-Koslowski, NORCID logo; Miller, M A; McCartney, TORCID logo
SourceAAPG ACE 2019 - American Association of Petroleum Geologists Annual Convention and Exhibition itinerary planner; P25, 2019 p. 1 Open Access logo Open Access
LinksOnline - En ligne
Alt SeriesNatural Resources Canada, Contribution Series 20180251
PublisherAmerican Association of Petroleum Geologists
MeetingAAPG ACE 2019 - American Association of Petroleum Geologists Annual Convention and Exhibition; San Antonio, TX; US; May 19-22, 2019
DocumentWeb site
Mediaon-line; digital
File formathtml
ProvinceNewfoundland and Labrador; Northern offshore region; Eastern offshore region
AreaLabrador; Labrador Sea
Lat/Long WENS -55.8833 -54.7000 54.9167 53.9333
Subjectsregional geology; stratigraphy; paleontology; sedimentology; continental margins; continental shelf; exploration wells; core samples; bedrock geology; lithology; sedimentary rocks; carbonates; limestones; dolomites; siltstones; sandstones; structural features; grabens; biostratigraphy; palynology; palynomorphs; spores; diagenesis; alteration; thermal maturation; thermal alteration; Labrador Margin; Hopedale E-33 Well; South Hopedale L- 39 Well; Tyrk P-100 Well; Gudrid H-55 Well; Roberval K-92 Well; Indian Harbour M-52 Well; Freydis B-87 Well; Hopedale Basin; Phanerozoic; Paleozoic; Carboniferous; Devonian; Ordovician
ProgramGEM2: Geo-mapping for Energy and Minerals Baffin Region Atlas
Released2019 05 01
AbstractPaleozoic strata is encountered in 7 wells located offshore Labrador, Canada (Hopedale E-33, South Hopedale L-39, Tyrk P-100, Gudrid H-55, Roberval K-92, Indian Harbour M-52, and Freydis B-87) where it represents erosional remnants now restricted primarily to the floors of select Cretaceous syn-rift half grabens in the Hopedale Basin. The Paleozoic section ranges from 4 m at Tyrk P-100 to over 400 m in thickness at Indian Harbour M-52 and is predominantly composed of carbonates (limestone and/or dolomite) with siliciclastics (siltstones and sandstones) accounting for over 300 m of strata in the Freydis B-87 well. Previous biostratigraphic analyses of this interval have been hindered by varying degrees of diagenetic alteration and associated limited palynological recovery, resulting in an assortment of ages including: undifferentiated Paleozoic, Ordovician, Devonian, and Carboniferous. Inconsistent age data and a lack of lateral continuity has prevented the correlation of Paleozoic strata along the Labrador margin at both a regional and global-scale. New biostratigraphic analyses of the Labrador margin Paleozoic strata was conducted on cuttings (7 wells) and core (4 wells) resulting in the observance of Upper Ordovician palynomorphs in 6 of the 7 wells, with no palynomorphs older than the Sandbian identified. The seventh well, Gudrid H-55, contained poorly preserved, undifferentiated lower Paleozoic palynomorphs; however, based on lithological resemblance and a similar degree of thermal maturation to other wells, specifically Roberval K-92, this interval is also interpreted as Upper Ordovician. Thermal maturity was determined from palynomorphs observed in Gudrid H-55, Roberval K-92, Indian Harbour M-52, and Freydis B-87 with thermal alteration indices (TAI) ranging from 5+ to 6 (dry gas). A significant amount of Carboniferous contamination is also noted in cuttings from these four wells with spores exhibiting TAIs of 3+ to 4 (immature to mature). This new biostratigraphic data demonstrates that the entire Paleozoic interval in the Hopedale Basin is Upper Ordovician in age, and correlations between wells are now possible. Additionally, the Paleozoic of the Labrador margin can now be correlated on a global-scale to other time-equivalent deposits in an attempt to further the understanding of Upper Ordovician paleoenvironments and the changes that occurred during this tectonically active period preceding the Ordovician-Silurian mass extinction.
Summary(Plain Language Summary, not published)
The Paleozoic of offshore Labrador has been poorly studied due to its discontinuous and restrictive nature. Previous age dating studies are limited and have resulted in a variety of inconsistent age dates ranging from undifferentiated Paleozoic, to Ordovician, to Devonian, to Carboniferous. New age dating was performed and resulted in an Upper Ordovician age for each of the seven wells that penetrate Paleozoic strata on the Labrador margin. Thermal maturity was also evaluated with all of the Upper Ordovician occurring in the dry gas range. This new age data now enables regional (well-to-well) and global-scale (comparison of the Labrador margin sediments to other, time-equivalent deposits located around the world) correlations to be made which will hopefully shed light on the Upper Ordovician period which is a significant tectonic (the start of the Appalachian orogeny) and evolutionary (mass extinction) interval in Earth's history.

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