Results 331 to 340 of about 75,496 (347)
Some of the next articles are maybe not open access.
2016
Based on trace-fossil evidence, the Cambrian explosion emerges as one of the most dramatic events in the history of the biosphere. Ichnologic data are highly valuable as an independent line of evidence with respect to the body-fossil record and molecular clocks to explore the nature of this event and the associated evolutionary innovations. In contrast
M. Gabriela Mángano, Luis A. Buatois
openaire +2 more sources
Based on trace-fossil evidence, the Cambrian explosion emerges as one of the most dramatic events in the history of the biosphere. Ichnologic data are highly valuable as an independent line of evidence with respect to the body-fossil record and molecular clocks to explore the nature of this event and the associated evolutionary innovations. In contrast
M. Gabriela Mángano, Luis A. Buatois
openaire +2 more sources
Palaeoworld, 2006
Abstract The Cambrian of Malaysia is best represented by the quartzose Machinchang Formation in Langkawi, Kedah, northwest Peninsular Malaysia. It is divisible into three members. The oldest Hulor Member (>1260 m thick) is a coarsening upward succession of rhythmically interlayered graded siltstone, mudstone and clayey sandstone deposited as a ...
openaire +2 more sources
Abstract The Cambrian of Malaysia is best represented by the quartzose Machinchang Formation in Langkawi, Kedah, northwest Peninsular Malaysia. It is divisible into three members. The oldest Hulor Member (>1260 m thick) is a coarsening upward succession of rhythmically interlayered graded siltstone, mudstone and clayey sandstone deposited as a ...
openaire +2 more sources
, 1978 Forty selected radiometric ages are plotted to illustrate a time scale for the Cambrian System and strata immediately above and below. Uncertainty is unavoidable at present, not only because the boundaries of the system are the subject of international working group investigations which are not complete, but also because the radiometric age ...
S. J. Cribb, J. W. Cowie
openaire +1 more source
Journal of the Geological Society of Australia, 1963
Abstract The Cambrian System by definition must include the rocks (in the Caledonian geosyncline of Wales) to which this name was first applied. Its type sequence, however, does not define its boundaries. Evidence on the base of the Cambrian can be found in the Caledonian sedimentary areas of Scandinavia and in the adjoining Baltic region where the ...
openaire +2 more sources
Abstract The Cambrian System by definition must include the rocks (in the Caledonian geosyncline of Wales) to which this name was first applied. Its type sequence, however, does not define its boundaries. Evidence on the base of the Cambrian can be found in the Caledonian sedimentary areas of Scandinavia and in the adjoining Baltic region where the ...
openaire +2 more sources
Research-Technology Management, 2013
"The future is already here--it's just not very evenly distributed. " William Gibson As this issue of RTM arrives in your mailbox, IRI--our publisher--enters its 75th year. It does so at what John Seely Brown would call a Cambrian moment for innovation, an era of explosive change with the potential to forge profound changes in the way we work, learn ...
openaire +2 more sources
"The future is already here--it's just not very evenly distributed. " William Gibson As this issue of RTM arrives in your mailbox, IRI--our publisher--enters its 75th year. It does so at what John Seely Brown would call a Cambrian moment for innovation, an era of explosive change with the potential to forge profound changes in the way we work, learn ...
openaire +2 more sources
Pre-Cambrian and Cambrian relations in the upper Mississippi Valley
Geological Society of America Bulletin, 1935INTRODUCTION This paper presents the results of an investigation of two of the stratigraphic problems of the upper Mississippi Valley, pointed out by Trowbridge and Atwater1 in 1934. At that time a review of the stratigraphy of the upper Mississippi Valley was given, a number of problems that the authors believed to be as yet unsolved were outlined ...
G. I. Atwater, G. M. Clement
openaire +2 more sources
Geological Society, London, Special Publications, 1964
Summary Fifteen selected radiometric ages are used to construct a time-scale for the Cambrian System. Maximum thicknesses are not considered to be useful in constructing a Cambrian time-scale. Ages of 495 m.y. and 570 m.y. are suggested for the top and base of the system, with ages of 540 m.y. and 515 m.y.
openaire +2 more sources
Summary Fifteen selected radiometric ages are used to construct a time-scale for the Cambrian System. Maximum thicknesses are not considered to be useful in constructing a Cambrian time-scale. Ages of 495 m.y. and 570 m.y. are suggested for the top and base of the system, with ages of 540 m.y. and 515 m.y.
openaire +2 more sources
1996
Within the Cambrian about six globally traceable extinction events are recognised, of which those across the Mid Botomian through to Toyonian/Amgan are of highest order. All events are associated with facies changes, mostly combined with stepwise extinctions that preferentially affected nearshore and endemic taxa.
openaire +2 more sources
Within the Cambrian about six globally traceable extinction events are recognised, of which those across the Mid Botomian through to Toyonian/Amgan are of highest order. All events are associated with facies changes, mostly combined with stepwise extinctions that preferentially affected nearshore and endemic taxa.
openaire +2 more sources
Pre-Cambrian atmosphere:evidence from the Pre-Cambrian of Sweden
Geochimica et Cosmochimica Acta, 1956Sedimentary haematite ores of central Sweden give evidence of the existence of an oxidizing atmosphere about 2000 × 106 years ago. This is not consistent with Rankama's conclusions from the unoxidized condition of a diorite conglomerate in Finland. Therefore a (later) Pre-Cambrian conglomerate in northern Sweden has been examined for comparison.
openaire +2 more sources