Eccentricity and obliquity paced carbon cycling in the Early Triassic and implications for post-extinction ecosystem recovery.
The timing of marine ecosystem recovery following the End Permian Mass Extinction (EPME) remains poorly constrained given the lack of radiometric ages. Here we develop a high-resolution carbonate carbon isotope (δ(13)Ccarb) record for 3.20 million years of the Olenekian in South China that defines the astronomical time-scale for the critical interval of major evolutionary and oceanic events in the Spathian. δ(13)Ccarb documents eccentricity modulation of carbon cycling through the period and a strong obliquity signal. A shift in phasing between short and long eccentricity modulation, and amplification of obliquity, is nearly coincident with a 2% decrease in seawater δ(13)CDIC, the last of a longer-term stepped decrease through the Spathian. The mid-Spathian shift in seawater δ(13)CDIC to typical thermocline values is interpreted to record a major oceanic reorganization with global climate amelioration. Coincidence of the phasing shift with the first occurrence of marine reptiles (248.81 Ma), suggests that their invasion into the sea and the onset of a complex ecosystem were facilitated by restoration of deep ocean ventilation linked mechanistically to a change in the response of the oceanic carbon reservoir to astronomical forcing. Together these records place the first constraints on the duration of the post-extinction recovery to 3.35 myr.
Laboratory of Orogenic Belt and Crustal Evolution, Ministry of Education; Department of Geology and Geological Museum, Peking University, Yiheyuan Street. 5, Beijing 100871, People's Republic of China.
Wanlu
W
Fu
Laboratory of Orogenic Belt and Crustal Evolution, Ministry of Education; Department of Geology and Geological Museum, Peking University, Yiheyuan Street. 5, Beijing 100871, People's Republic of China.
Da-Yong
DY
Jiang
Department of Earth and Planetary Sciences, University of California, Davis, One Shields Avenue, Davis, California 95616, USA.
Isabel P
IP
Montañez
Department of Geoscience, University of Wisconsin, 1215 West Dayton St, Madison, WI 53076, USA.
Stephen R
SR
Meyers
Department of Earth and Planetary Sciences, University of California, Davis, One Shields Avenue, Davis, California 95616, USA.
Ryosuke
R
Motani
Dipartimento di Scienze della Terra, Università degli Studi di Milano, Via Mangiagalli 34-20133 Milano, Italy.
Andrea
A
Tintori
D000818:Animals; D057486:Carbon Cycle; D002247:Carbon Isotopes / Q000032:analysis*; D017753:Ecosystem; D053476:Extinction, Biological; D005580:Fossils; D010163:Paleontology; D012104:Reptiles; D012623:Seawater / Q000737:chemistry*
D002247:Carbon Isotopes