TY - JOUR
T1 - New constraints on the evolution of 87Sr/86Sr of seawater during the Upper Triassic
AU - Kovács, Zsófia
AU - Demangel, Isaline
AU - Richoz, Sylvain
AU - Hippler, Dorothee
AU - Baldermann, Andre
AU - Krystyn, Leopold
PY - 2020/9
Y1 - 2020/9
N2 - The Late Triassic time interval witnessed several important biological turnovers, extinctions and onset of new life forms. Therefore, it is crucial to better constrain the tectonic, climatic and oceanographic framework at this time. The radiogenic strontium isotopic composition (87Sr/86Sr) of seawater, recorded in marine carbonates is sensitive to variations in continental weathering and oceanic spreading rates. This makes it a powerful proxy for palaeo-environmental reconstructions and an excellent global stratigraphic correlation tool of marine sediment records. In this study, we present a new and extended 87Sr/86Sr dataset across the late Norian - Hettangian interval, established from carbonate successions in Austria and Turkey. The well-established biostratigraphy and high sampling resolution allow evaluating changes in the 87Sr/86Sr record with a better time constraint than in previous studies. An exceptionally sharp trend towards unradiogenic values has been observed in the latest Norian and in the early Rhaetian from 0.70800 to 0.70779. Considering Late Triassic climate change, updated tectonic models and actual dating of magmatic events, possible explanations for the observed trend in the 87Sr/86Sr record are: (i) enhanced dissolution of pre-Norian carbonates, (ii) dissolution of widespread Late Triassic evaporites and (iii) tectonic reorganization of sedimentary basins due to the break-up of the supercontinent Pangea. At the very end of the Choristoceras marshi Zone, in the late Rhaetian, the unradiogenic 87Sr/86Sr trend is reversed. This is likely related to environmental changes due to the continental emplacement of the Central Atlantic Magmatic Province.
AB - The Late Triassic time interval witnessed several important biological turnovers, extinctions and onset of new life forms. Therefore, it is crucial to better constrain the tectonic, climatic and oceanographic framework at this time. The radiogenic strontium isotopic composition (87Sr/86Sr) of seawater, recorded in marine carbonates is sensitive to variations in continental weathering and oceanic spreading rates. This makes it a powerful proxy for palaeo-environmental reconstructions and an excellent global stratigraphic correlation tool of marine sediment records. In this study, we present a new and extended 87Sr/86Sr dataset across the late Norian - Hettangian interval, established from carbonate successions in Austria and Turkey. The well-established biostratigraphy and high sampling resolution allow evaluating changes in the 87Sr/86Sr record with a better time constraint than in previous studies. An exceptionally sharp trend towards unradiogenic values has been observed in the latest Norian and in the early Rhaetian from 0.70800 to 0.70779. Considering Late Triassic climate change, updated tectonic models and actual dating of magmatic events, possible explanations for the observed trend in the 87Sr/86Sr record are: (i) enhanced dissolution of pre-Norian carbonates, (ii) dissolution of widespread Late Triassic evaporites and (iii) tectonic reorganization of sedimentary basins due to the break-up of the supercontinent Pangea. At the very end of the Choristoceras marshi Zone, in the late Rhaetian, the unradiogenic 87Sr/86Sr trend is reversed. This is likely related to environmental changes due to the continental emplacement of the Central Atlantic Magmatic Province.
KW - Hettangian
KW - Norian
KW - Palaeo-environment
KW - Radiogenic strontium
KW - Rhaetian
KW - Seawater evolution
KW - Triassic/Jurassic boundary
UR - http://www.scopus.com/inward/record.url?scp=85086461587&partnerID=8YFLogxK
U2 - 10.1016/j.gloplacha.2020.103255
DO - 10.1016/j.gloplacha.2020.103255
M3 - Article
AN - SCOPUS:85086461587
SN - 0921-8181
VL - 192
JO - Global and Planetary Change
JF - Global and Planetary Change
M1 - 103255
ER -