| Title | Updated lithological, biostratigraphic, and thermal alteration data for the lLower Paleozoic, offshore Labrador, Canada |
| |
| Author | Bingham-Koslowski, N ; Miller, M A; McCartney, T |
| Source | AAPG ACE 2019 - American Association of Petroleum Geologists Annual Convention and Exhibition itinerary planner; P25, 2019 p. 1  Open Access |
| Links | Online - En ligne
|
| Image |  |
| Year | 2019 |
| Alt Series | Natural Resources Canada, Contribution Series 20180251 |
| Publisher | American Association of Petroleum Geologists |
| Meeting | AAPG ACE 2019 - American Association of Petroleum Geologists Annual Convention and Exhibition; San Antonio, TX; US; May 19-22, 2019 |
| Document | Web site |
| Lang. | English |
| Media | on-line; digital |
| File format | html |
| Province | Newfoundland and Labrador; Northern offshore region; Eastern offshore region |
| NTS | 3 |
| Area | Labrador; Labrador Sea |
| Lat/Long WENS | -55.8833 -54.7000 54.9167 53.9333 |
| Subjects | regional 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 |
| Program | GEM2: Geo-mapping for Energy and Minerals Baffin Region Atlas |
| Released | 2019 05 01 |
| Abstract | Paleozoic 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. |
| GEOSCAN ID | 312327 |
|
|