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TitleContinental weathering and recovery from ocean nutrient stress during the Early Triassic Biotic Crisis
AuthorKnies, J; Schönenberger, J; Zwingmann, H; van der Lelij, RX; Smelror, M; Vullum, P E; Brönner, M; Vogt, C; Fredin, O; Müller, A; Grasby, S EORCID logo; Beauchamp, B; Viola, G
SourceCommunications Earth & Environment 161, 2022 p. 1-12, Open Access logo Open Access
Alt SeriesNatural Resources Canada, Contribution Series 20220030
PublisherSpringer Nature
Mediapaper; digital; on-line
File formatpdf; html
ProvinceCanada; British Columbia; Alberta; Saskatchewan; Manitoba; Ontario; Quebec; New Brunswick; Nova Scotia; Prince Edward Island; Newfoundland and Labrador; Northwest Territories; Yukon; Nunavut
NTS1; 2; 3; 10; 11; 12; 13; 14; 15; 16; 20; 21; 22; 23; 24; 25; 26; 27; 28; 29; 30; 31; 32; 33; 34; 35; 36; 37; 38; 39; 40; 41; 42; 43; 44; 45; 46; 47; 48; 49; 52; 53; 54; 55; 56; 57; 58; 59; 62; 63; 64; 65; 66; 67; 68; 69; 72; 73; 74; 75; 76; 77; 78; 79; 82; 83; 84; 85; 86; 87; 88; 89; 92; 93; 94; 95; 96; 97; 98; 99; 102; 103; 104; 105; 106; 107; 114O; 114P; 115; 116; 117; 120; 340; 560
Lat/Long WENS-180.0000 180.0000 90.0000 -90.0000
SubjectsScience and Technology; Nature and Environment; marine ecology; Triassic
Illustrationslocation maps; satellite imagery; photomicrographs; diagrams; cross-plots
ProgramTargeted Geoscience Initiative (TGI-6) Ore systems
Released2022 07 15
AbstractFollowing the latest Permian extinction ~252 million years ago, normal marine and terrestrial ecosystems did not recover for another 5-9 million years. The driver(s) for the Early Triassic biotic crisis, marked by high atmospheric CO2 concentration, extreme ocean warming, and marine anoxia, remains unclear. Here we constrain the timing of authigenic K-bearing mineral formation extracted from supergene weathering profiles of NW-Pangea by Argon geochronology, to demonstrate that an accelerated hydrological cycle causing intense chemical alteration of the continents occurred between ~254 and 248 Ma, and continued throughout the Triassic period. We show that enhanced ocean nutrient supply from this intense continental weathering did not trigger increased ocean productivity during the Early Triassic biotic crisis, due to strong thermal ocean stratification off NW Pangea. Nitrogen isotope constraints suggest, instead, that full recovery from ocean nutrient stress, despite some brief amelioration ~1.5 million years after the latest Permian extinction, did not commence until climate cooling revitalized the global upwelling systems and ocean mixing ~10 million years after the mass extinction.
Summary(Plain Language Summary, not published)
Early to Middle Triassic age rock in the circum-arctic region show an unusual trend of initially being very depleted in organic matter and then shifting to very high organic matter content that is also enriched in phophorites as well as rare earth elements. The processes that caused this shift have been enigmatic. This study examined the paleo-ocean and land conditions of the northern land masses at that time to ascertain the nutrient loads to the oceans. Results showed that while there was abundant weathering of the land and flux of soil to the oceans, this did not initially affect marine primary productivity as nutrients were trapped in a thermally stratified ocean under extreme greenhouse conditions. Once the Earth returned to a more normal climate state high productivity conditions developed leading to formation of phosphorites.

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