A5031766393- Geology and Paleoclimatology Research
- Paleontology and Stratigraphy of Fossils
- Geological and Geochemical Analysis
- Geological Studies and Exploration
- Geochemistry and Geologic Mapping
- Geological formations and processes
- earthquake and tectonic studies
- Geological and Geophysical Studies
- Methane Hydrates and Related Phenomena
- High-pressure geophysics and materials
- Geomagnetism and Paleomagnetism Studies
- Polar Research and Ecology
- Geochemistry and Elemental Analysis
- Astro and Planetary Science
- Neurobiology of Language and Bilingualism
- Marine and environmental studies
- Planetary Science and Exploration
- Natural Language Processing Techniques
- Marine Biology and Ecology Research
- Language, Metaphor, and Cognition
- Hydrocarbon exploration and reservoir analysis
- Geophysics and Gravity Measurements
- Geological Formations and Processes Exploration
- Topic Modeling
- Isotope Analysis in Ecology
Harvard University
2016-2025
University of Victoria
2016-2025
Planetary Science Institute
2016-2025
University of Edinburgh
2021-2024
Harvard University Press
2006-2016
Johns Hopkins University
1967-2015
Montrose Center
2012-2014
Geological Survey of Canada
1982-2013
St. Francis Xavier University
2013
Memorial University of Newfoundland
2013
Negative carbon isotope anomalies in carbonate rocks bracketing Neoproterozoic glacial deposits Namibia, combined with estimates of thermal subsidence history, suggest that biological productivity the surface ocean collapsed for millions years. This collapse can be explained by a global glaciation (that is, snowball Earth), which ended abruptly when subaerial volcanic outgassing raised atmospheric dioxide to about 350 times modern level. The rapid termination would have resulted warming...
Comparative geology suggests that the continents adjacent to northern, western, southern, and eastern Laurentia in Late Proterozoic were Siberia, Australia-Antarctica, southern Africa, Amazonia-Baltica, respectively. fragmentation of supercontinent centered on would then have been followed by rapid fan-like collapse (present) eventual consolidation East West Gondwanaland. In this scenario, a pole rotation near Weddell Sea explain observed dominance wrench tectonics east-west trending...
The gradual discovery that late Neoproterozoic ice sheets extended to sea level near the equator poses a palaeoenvironmental conundrum. Was Earth's orbital obliquity > 60° (making tropics colder than poles) for 4.0 billion years following lunar‐forming impact, or did climate cool globally some reason point at which runaway ice‐albedo feedback created `snowball' Earth? high‐obliquity hypothesis does not account major features of glacial record such as abrupt onsets and terminations...
Research Article| September 01, 2005 Toward a Neoproterozoic composite carbon-isotope record Galen P. Halverson; Halverson 1Department of Earth and Planetary Sciences, Harvard University, 20 Oxford Street, Cambridge, Massachusetts 02138-2902, USA, Department Earth, Atmospheric, Institute Technology, Building 54-1126, 02139, USA Search for other works by this author on: GSW Google Scholar Paul F. Hoffman; Hoffman 2Department Daniel Schrag; Schrag Adam C. Maloof; Maloof A. Hugh N. Rice...
We review recent observations and models concerning the dynamics of Cryogenian global glaciation their biological consequences.
Research Article| February 01, 1989 Speculations on Laurentia's first gigayear (2.0 to 1.0 Ga) Paul F. Hoffman 1Lithosphere and Canadian Shield Division, Geological Survey of Canada, Ottawa, Ontario K1A 0E4, Canada Search for other works by this author on: GSW Google Scholar Author Article Information Publisher: Society America First Online: 02 Jun 2017 Online ISSN: 1943-2682 Print 0091-7613 Geology (1989) 17 (2): 135–138. https://doi.org/10.1130/0091-7613(1989)017<0135:SOLSFG>2.3.CO;2...
The Snowball Earth hypothesis explains the development of glaciation at low latitudes in Neoproterozoic, as well associated iron formations and cap carbonates, terms a runaway ice‐albedo feedback leading to global followed by an extreme greenhouse climate. initiation snowball is linked variety unusual perturbations carbon cycle operating over different timescales, evidenced patterns isotopic composition marine carbonate. Thus theory for why multiple glaciations happened this time, not...
Abstract The Otavi Group is a Neoproterozoic carbonate‐dominated succession up to 4 km thick, which blankets the southern promontory of Congo craton in northern Namibia. This was deposited between 770 and 580 Ma response north–south crustal stretching subsequent thermal subsidence. main shallow‐water platform has well‐defined limit, beyond distally tapered foreslope wedge deep‐water carbonate facies. Ghaub Formation represents younger two Cryogenian glaciations during period A deep negative...
Fe speciation and S-isotope of pyrite data from the terminal Proterozoic Sheepbed Formation in Canada Doushantuo China reveal that ocean deep waters were anoxic after global glaciations (snowball Earth) ending 635 million years ago, but marine sulfate concentrations inferentially atmospheric oxygen levels higher than before glaciations. This supports a long-postulated link between emergence eumetazoa. Subsequent ventilation ocean, inferred shifts Newfoundland (previously published data)...
The Coronation geosyncline developed in the early Proterozoic along western margin of a continental platform (the Slave Province) Archaean rocks older than 2300 Ma, and culminated between 1725 1855 Ma ago with emplacement pair batholiths Bear Province). evolution has strong family resemblance to Phanerozoic geosynclines believed delineate ancient margins have been controlled by global plate interactions. Such are unknown orogenic belts, from which it is inferred that creation first large...
Research Article| February 01, 1984 Short-lived 1.9 Ga continental margin and its destruction, Wopmay orogen, northwest Canada Paul F. Hoffman; Hoffman 1Geological Survey of Canada, Ottawa, Ontario K1A OE4, Search for other works by this author on: GSW Google Scholar Samuel A. Bowring 2Department Geology, University Kansas, Lawrence, Kansas 66045 Author Article Information Publisher: Geological Society America First Online: 01 Jun 2017 Online ISSN: 1943-2682 Print 0091-7613 Geology (1984) 12...