Occurrence of Structurally Preserved Plants in Pre-Cambrian Rocks of the Canadian Shield

Tyler, S. A.; Barghoorn, Elso S.

doi:10.1126/science.119.3096.606

Cited by 240 publications

(74 citation statements)

References 5 publications

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“…The oldest likely eukaryotic body fossil, Grypania spiralis, is found in the c. 1.88 Ga Negaunee iron-formation (Han & Runnegar 1992;Schneider et al 2002), coeval with the spectacular palaeontological record of the nearby Gunflint Chert (Tyler & Barghoorn 1954;Fralick et al 2002) and only slightly younger than the equally impressive Belcher Islands microflora (Hofmann 1976) at c. 2.0 Ga (Chandler & Parrish 1989). Classification of Grypania is based on its morphological similarity to Mesoproterozoic occurrences from North China and North America (Walter et al 1990).…”

Section: The Evolving Palaeoclimate and Biospherementioning

confidence: 99%

Palaeoproterozoic supercontinents and global evolution: correlations from core to atmosphere

Reddy

Evans

2009

115

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The Palaeoproterozoic era was a time of profound change in Earth evolution and represented perhaps the first supercontinent cycle, from the amalgamation and dispersal of a possible Neoarchaean supercontinent to the formation of the 1.9-1.8 Ga supercontinent Nuna. This supercontinent cycle, although currently lacking in palaeogeographic detail, can in principle provide a contextual framework to investigate the relationships between deep-Earth and surface processes. In this article, we graphically summarize secular evolution from the Earth's core to its atmosphere, from the Neoarchaean to the Mesoproterozoic eras (specifically 3.0-1.2 Ga), to reveal intriguing temporal relationships across the various 'spheres' of the Earth system. At the broadest level our compilation confirms an important deep-Earth event at c. 2.7 Ga that is manifested in an abrupt increase in geodynamo palaeointensity, a peak in the global record of large igneous provinces, and a broad maximum in several mantle-depletion proxies. Temporal coincidence with juvenile continental crust production and orogenic gold, massive-sulphide and porphyry copper deposits, indicate enhanced mantle convection linked to a series of mantle plumes and/or slab avalanches. The subsequent stabilization of cratonic lithosphere, the possible development of Earth's first supercontinent and the emergence of the continents led to a changing surface environment in which voluminous banded iron-formations could accumulate on the continental margins and photosynthetic life could flourish. This in turn led to irreversible atmospheric oxidation at 2.4-2.3 Ga, extreme events in global carbon cycling, and the possible dissipation of a former methane greenhouse atmosphere that resulted in extensive Palaeoproterozoic ice ages. Following the great oxidation event, shallow marine sulphate levels rose, sediment-hosted and iron-oxide-rich metal deposits became abundant, and the transition to sulphide-stratified oceans provided the environment for early eukaryotic evolution. Recent advances in the geochronology of the global stratigraphic record have made these inferences possible. Frontiers for future research include more refined modelling of Earth's thermal and geodynamic evolution, palaeomagnetic studies of geodynamo intensity and continental motions, further geochronology and tectonic syntheses at regional levels, development of new isotopic systems to constrain geochemical cycles, and continued innovation in the search for records of early life in relation to changing palaeoenvironments.

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Section: The Evolving Palaeoclimate and Biospherementioning

confidence: 99%

Palaeoproterozoic supercontinents and global evolution: correlations from core to atmosphere

Reddy

Evans

2009

115

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“…It was not until the 1950s and 1960s that definitive fossils were described from the Gunflint Chert Tyler 1963, 1965;Tyler and Barghoorn 1954), a 1.88-billion-year-old shallow-water deposit exposed in Minnesota and Ontario on the northern shore of Lake Superior (Fralick et al 2002). Additional fossil finds and geochemical data have since extended the record of life back another 2 billion years (Allwood et al 2006;Mojzsis et al 1996;Rosing 1999;Schidlowski et al 1979;Schopf 1993;Schopf and Packer 1987;Tice and Lowe 2004).…”

Section: Introductionmentioning

confidence: 99%

The evolutionary consequences of oxygenic photosynthesis: a body size perspective

et al. 2010

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The high concentration of molecular oxygen in Earth's atmosphere is arguably the most conspicuous and geologically important signature of life. Earth's early atmosphere lacked oxygen; accumulation began after the evolution of oxygenic photosynthesis in cyanobacteria around 3.0-2.5 billion years ago (Gya). Concentrations of oxygen have since varied, first reaching near-modern values ~600 million years ago (Mya). These fluctuations have been hypothesized to constrain many biological patterns, among them the evolution of body size. Here, we review the state of knowledge relating oxygen availability to body size. Laboratory studies increasingly illuminate the mechanisms by which organisms can adapt physiologically to the variation in oxygen availability, but the extent to which these findings can be extrapolated to evolutionary timescales remains poorly understood. Experiments confirm that animal size is limited by experimental hypoxia, but show that plant vegetative growth is enhanced due to

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“…First, Tyler & Barghoorn (1954;Barghoorn & Tyler 1965) documented bacterial microfossils in ca. 1,880-million-year-old chert, more than tripling the length of life's known history on Earth.…”

Section: Introductionmentioning

confidence: 99%

The Ecological Physiology of Earth's Second Oxygen Revolution

Sperling

Knoll

Girguis

2015

Annu. Rev. Ecol. Evol. Syst.

130

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Living animals display a variety of morphological, physiological, and biochemical characters that enable them to live in low-oxygen environments. These features and the organisms that have evolved them are distributed in a regular pattern across dioxygen (O 2 ) gradients associated with modern oxygen minimum zones. This distribution provides a template for interpreting the stratigraphic covariance between inferred Ediacaran-Cambrian oxygenation and early animal diversification. Although Cambrian oxygen must have reached 10--20% of modern levels, sufficient to support the animal diversity recorded by fossils, it may not have been much higher than this.Today's levels may have been approached only later in the Paleozoic Era. Nonetheless, Ediacaran-Cambrian oxygenation may have pushed surface environments across the low, but critical, physiological thresholds required for large, active animals, especially carnivores. Continued focus on the quantification of the partial pressure of oxygen (pO 2 ) in the Proterozoic will provide the definitive tests of oxygen-based coevolutionary hypotheses.

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Occurrence of Structurally Preserved Plants in Pre-Cambrian Rocks of the Canadian Shield

Cited by 240 publications

References 5 publications

Palaeoproterozoic supercontinents and global evolution: correlations from core to atmosphere

Palaeoproterozoic supercontinents and global evolution: correlations from core to atmosphere

The evolutionary consequences of oxygenic photosynthesis: a body size perspective

The Ecological Physiology of Earth's Second Oxygen Revolution

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