An early Cambrian greenhouse climate

• Published in: Science Advances
• Main Authors: Wong Hearing, Thomas, Harvey, Thomas H. P., Williams, Mark, Leng, Melanie J., Lamb, Angela L., Wilby, Philip R., Gabbott, Sarah E., Pohl, Alexandre, Donnadieu, Yannick
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2018
• Subjects: Earth and Environmental Sciences; stable oxygen isotopes; sea surface temperature; Cambrian; small shelly fossils; greenhouse climate; OXYGEN ISOTOPIC COMPOSITION; SEA-SURFACE TEMPERATURE; EOCENE THERMAL MAXIMUM; PLANKTONIC-FORAMINIFERA; ATMOSPHERIC CO2; OCEAN; ORDOVICIAN; PHOSPHATE; PACIFIC; DELTA-O-18; Pacific; Planktonic foraminifera
• Online Access: https://biblio.ugent.be/publication/8695452; http://hdl.handle.net/1854/LU-8695452; https://doi.org/10.1126/sciadv.aar5690; https://biblio.ugent.be/publication/8695452/file/8695483

The oceans of the early Cambrian (similar to 541 to 509 million years ago) were the setting for a marked diversification of animal life. However, sea temperatures-a key component of the early Cambrian marine environment-remain unconstrained, in part because of a substantial time gap in the stable oxygen isotope (delta O-18) record before the evolution of euconodonts. We show that previously overlooked sources of fossil biogenic phosphate have the potential to fill this gap. Pristine phosphatic microfossils from the Comley Limestones, UK, yield a robust delta O-18 signature, suggesting sea surface temperatures of 20 degrees to 25 degrees C at high southern paleolatitudes (similar to 65 degrees S to 70 degrees S) between similar to 514 and 509 million years ago. These sea temperatures are consistent with the distribution of coeval evaporite and calcrete deposits, peak continental weathering rates, and also our climate model simulations for this interval. Our results support an early Cambrian greenhouse climate comparable to those of the late Mesozoic and early Cenozoic, offering a framework for exploring the interplay between biotic and environmental controls on Cambrian animal diversification.