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TitleThe palynostratigraphy, age, and environment of strata penetrated by the Mallik 5L-38 gas-hydrate research well, Northwest Territories, determined by differentiating the recycled and contemporaneous palynomorphs
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AuthorWhite, J M
SourceGeological Survey of Canada, Bulletin 604, 2014, 85 pages (3 sheets), https://doi.org/10.4095/295079
Year2014
PublisherNatural Resources Canada
Documentserial
Lang.English
Mediaon-line; digital
RelatedThis publication supercedes White, J M; (2012). The palynostratigraphy, age and environment of strata penetrated by the Mallik 5L-38 gas hydrate research well determined by differentiating the recycled and contemporaneous palynomorphs, Geological Survey of Canada, Open File 6882
RelatedThis publication is superceded by White, J M; (2015). The palynostratigraphy, age, and environment of strata penetrated by the Mallik 5L-38 gas-hydrate research well, Northwest Territories, determined by differentiating the recycled and contemporaneous palynomorphs, Geological Survey of Canada, Bulletin no. 604, ed. rev.
File formatpdf
ProvinceNorthwest Territories
NTS107C/06NW
AreaMackenzie Delta; Beaufort Sea
Lat/Long WENS-134.7500 -134.5000 69.5000 69.4167
Subjectsfossil fuels; paleontology; palynological analyses; palynology; palynomorphs; palynostratigraphy; paleoclimates; hydrocarbons; gas; hydrocarbon gases; hydrate; methane; methane hydrate; petroleum resources; Mallik 5L-38; Mallik 2L; Tertiary; Cenozoic; Quaternary
Illustrationslocation maps; profiles; plots
ProgramMackenzie Corridor Project Management, GEM2: Geo-mapping for Energy and Minerals
LinksErratum
Released2014 12 17
AbstractQuantitative palynostratigraphy of the Mallik 5L-38 well provides insight into palynomorph recycling and a Late Eocene age for the basal coals. Samples from 450 m to 900 m yielded a fraction on the 180 ?m screen having a high concentration of recycled palynomorphs, releasable by standard oxidation. The fraction that passed through the screen was not oxidized and yielded more in-place palynomorphs. This observation may affect interpretation of other regional upper Cenozoic studies of oxidized samples. The 0-270 m interval is interpreted to be late Pliocene to Pleistocene. The regional erosional unconformity below the Iperk Sequence is identified at 340 m, with other possible unconformities at 445 m and 550 m. The interval from 340 m to 700 m is thought to be Early Miocene. The 700-900 m interval is tentatively identified as Oligocene. Climate proxy ratios, compared with those of Mallik 2L-38 well between 670 m and 900 m are inconsistent, possibly due to low palynomorph counts or a change from a coherent Late Eocene record to a noisy Oligocene and younger record. An erosional unconformity near 930 m may have resulted from sea-level decline due to earliest Oligocene glaciation in Antarctica. Core samples from coal beds between 933.65 m and 1081.90 m yielded Late Eocene palynomorphs unlikely to be recycled, and some pollen associated with earlier Eocene ages. The coal swamps seem to be an environment where relict species can persist. A warm paleoclimate is indicated, consistent with an Eocene age.
Summary(Plain Language Summary, not published)
In the hydrocarbon-hosting Beaufort-Mackenzie Basin, study of pollen and spores from Mallik 5L-38 well clarifies redeposition of organic matter and ages for strata. Samples from 450 to 900 m yielded two fractions. The fraction retained on a 180 micrometre screen yielded more recycled palynomorphs, when oxidized, than the fraction that passed through the screen. This observation affects interpretation of other regional upper Cenozoic palynological studies. Intervals of non-deposition or erosion were identified at 340, 445 and 550 m. The 0 to 270 m interval is younger than 3 million years (myr) old. From 340 to 700 m is ~20 myr old and from 700 to 900 m is ~28 myr old. Significant erosion near 930 m may have resulted from Antarctic glaciation-induced sea level fall. Coals between 933.65 and 1081.90 m are Late Eocene, about 34 myr old. Wetlands seem to have been an environment where relict species could persist. A warm paleoclimate is indicated, consistent with the Eocene age.
GEOSCAN ID295079