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TitleAncestral trans-North American Bell River system recorded in late Oligocene to early Miocene sediments in the Labrador Sea and Canadian Great Plains
AuthorCorradino, J I; Pullen, A; Leier, A L; Barbeau, D L, Jr; Scher, H D; Weislogel, A; Bruner, A; Leckie, D A; Currie, L DORCID logo
SourceGeological Society of America Bulletin 2021 p. 1-15,
Alt SeriesNatural Resources Canada, Contribution Series 20210427
PublisherGeological Society of America
Mediapaper; digital; on-line
File formatpdf
ProvinceNewfoundland and Labrador; Northern offshore region
AreaLabrador; Labrador Sea
Lat/Long WENS -64.0000 -60.0000 60.0000 58.0000
Subjectsgeochronology; paleontology; geochemistry; Science and Technology; Nature and Environment; Neogene; Miocene; Paleogene; Oligocene; paleodrainage; drainage systems; drainage patterns; paleocurrents; paleocurrent directions; sediment transport; continental margins; continental shelf; radiometric dating; uranium lead dating; zircon dates; detrital minerals; strontium strontium ratios; neodymium geochemistry; bedrock geology; lithology; sedimentary rocks; conglomerates; fossils; oceanography; sea water geochemistry; stratification; current circulation; paleoenvironment; Saglek Basin; Rut H-11 Well; Ancestral Bell River; Interior Plains; Great Plains; Mokami Formation; Saglek Formation; Canadian Cordillera; Labrador Current; Phanerozoic; Cenozoic; Tertiary
Illustrationsgeoscientific sketch maps; stratigraphic columns; geophysical logs; profiles; time series; bar graphs
ProgramGEM2: Geo-mapping for Energy and Minerals Baffin Region
Released2021 04 20
AbstractThe Bell River hypothesis proposes that an ancestral, transcontinental river occupied much of northern North America during the Cenozoic Era, transporting water and sediment from the North American Cordillera to the Saglek Basin on the eastern margin of the Labrador Sea. To explore this hypothesis and reconstruct Cenozoic North American drainage patterns, we analyzed detrital zircon grains from the Oligocene-Miocene Mokami and Saglek formations of the Saglek Basin and Oligocene-Miocene fluvial conglomerates in the Great Plains of western Canada. U-Pb detrital zircon age populations in the Mokami and Saglek formations include clusters at <250 Ma, 950-1250 Ma, 1600-2000 Ma, and 2400-3200 Ma. Detrital zircons with ages of <250 Ma were derived from the North American Cordillera, supporting the transcontinental Bell River hypothesis. Oligocene-Miocene fluvial strata in western Canada contain detrital zircon age populations similar to those in the Saglek Basin and are interpreted to represent the western headwaters of the ancient Bell River drainage. Strontium-isotope ratios of marine shell fragments from the Mokami and Saglek formations yielded ages between 25.63 and 18.08 Ma. The same shells have epsilon-Nd values of -10.2 to -12.0 (average = -11.2), which are consistent with values of Paleozoic strata in western North America but are more radiogenic than the modern Labrador Current, Labrador Sea Water, and North Atlantic Deep Water values (epsilon-Nd ~-12 to -25). As a freshwater source, the existence and termination of the Bell River may have been important for Labrador Sea circulation, stratification, and chemistry.
Summary(Plain Language Summary, not published)
Deltaic sediments that were deposited in the Saglek Basin of the Labrador Sea between about 34 and 2.6 million years ago are believed to be the product of a transcontinental fluvial system called the ancestral Bell River. We dated detrital zircon grains from the approximately 34 to 18 million year old Mokami and Saglek formations of the Saglek Basin as well as similar age fluvial conglomerates in the Great Plains of western Canada to examine past North American drainage patterns and test the Bell River hypothesis. U-Pb detrital zircon ages in the Mokami and Saglek formations are consistent with source areas in the Canadian Cordillera and the northern U.S. Rockies. Paleocurrent data and detrital zircons less than 250 million years old from the fluvial samples from the Canadian Great Plains provide evidence that these units were once part of the Bell River system and delineate the spatial extent of the drainage catchment. Strontium isotopes of marine shells from the upper Mokami and Saglek formations yielded ages between 25.63 and 18.08 Ma. Shell fragments have isotopic signatures which overlap with those of Paleozoic miogeocline strata in western North America, and importantly, are more radiogenic than the modern Labrador Current, Labrador Sea Water, and North Atlantic Deep Water. Collectively, these data support a connection between the North American Cordillera, the Bell River, and Labrador Sea during (at least) 25.62 and 18.08 million years ago. The Bell River should be considered for its effect on ocean chemistry in investigations of Atlantic Ocean circulation during this time period.

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