Claypool continued: Extending the isotopic record of sedimentary sulfate

PW Crockford, M Kunzmann, A Bekker, J Hayles… - Chemical …, 2019 - Elsevier
Abstract The Proterozoic Eon spans Earth's middle age during which many important
transitions occurred. These transitions include the oxygenation of the atmosphere …

Snowballs in Africa: sectioning a long-lived Neoproterozoic carbonate platform and its bathyal foreslope (NW Namibia)

PF Hoffman, GP Halverson, DP Schrag, JA Higgins… - Earth-Science …, 2021 - Elsevier
Abstract Otavi Group is a 1.5–3.5-km-thick epicontinental marine carbonate succession of
Neoproterozoic age, exposed in an 800-km-long Ediacaran− Cambrian fold belt that rims …

Snowball Earth climate dynamics and Cryogenian geology-geobiology

PF Hoffman, DS Abbot, Y Ashkenazy, DI Benn… - Science …, 2017 - science.org
Geological evidence indicates that grounded ice sheets reached sea level at all latitudes
during two long-lived Cryogenian (58 and≥ 5 My) glaciations. Combined uranium-lead and …

Triple oxygen isotope evidence for limited mid-Proterozoic primary productivity

PW Crockford, JA Hayles, H Bao, NJ Planavsky… - Nature, 2018 - nature.com
The global biosphere is commonly assumed to have been less productive before the rise of
complex eukaryotic ecosystems than it is today. However, direct evidence for this assertion …

A productivity collapse to end Earth's Great Oxidation

MSW Hodgskiss, PW Crockford… - Proceedings of the …, 2019 - National Acad Sciences
It has been hypothesized that the overall size of—or efficiency of carbon export from—the
biosphere decreased at the end of the Great Oxidation Event (GOE)(ca. 2,400 to 2,050 Ma) …

Two-billion-year-old evaporites capture Earth's great oxidation

CL Blättler, MW Claire, AR Prave, K Kirsimäe… - Science, 2018 - science.org
Major changes in atmospheric and ocean chemistry occurred in the Paleoproterozoic era
(2.5 to 1.6 billion years ago). Increasing oxidation dramatically changed Earth's surface, but …

An early diagenetic deglacial origin for basal Ediacaran “cap dolostones”

ASC Ahm, AC Maloof, FA Macdonald… - Earth and Planetary …, 2019 - Elsevier
The beginning of the Ediacaran Period (∼ 635 Ma) is marked by conspicuous dolostone
units that cap Marinoan glacial deposits worldwide. The extent and sedimentary …

Interlinked marine cycles of methane, manganese, and sulfate in the post-Marinoan Doushantuo cap dolostone

C Cai, D Liu, Y Hu, T Huang, Z Jiang, C Xu - Geochimica et Cosmochimica …, 2023 - Elsevier
The strongly 13 C-depleted calcite in the Doushantuo cap dolostones (∼ 635 Ma) of South
China is considered to form via thermochemical or biological oxidation of methane by sulfate …

Barium-isotopic constraints on the origin of post-Marinoan barites

PW Crockford, BA Wing, A Paytan… - Earth and Planetary …, 2019 - Elsevier
Measurements of triple oxygen isotope ratios in barite horizons within post-Marinoan cap
carbonates have provided some of the most compelling evidence that the Marinoan …

A transient peak in marine sulfate after the 635-Ma snowball Earth

Y Peng, H Bao, G Jiang, P Crockford… - Proceedings of the …, 2022 - National Acad Sciences
A series of dramatic oceanic and atmospheric events occurred in the immediate aftermath of
the Marinoan “snowball Earth” meltdown∼ 635 My ago. However, at the 10-to 100-ky …