Hundreds of Millions of Years of Change in Cordilleran Terranes of Western North America
This month’s science article, by Todd LaMaskin of the University of North Carolina at Wilmington, presents uranium-lead dating analyses of detrital zircon grains in Paleozoic-Mesozoic basin sediments in the Cordillera of western North America.
LaMaskin's analysis shows a systematic variation in age distribution within the depositional age and setting of the host sediments. Four such age distributions, which he terms “detrital zircon facies,” are identified:
(1) a Paleoproterozoic-Archean facies mainly found in Paleozoic and early Mesozoic accretionary complexes;
(2) a Proterozoic-Phanerozoic facies found in Jurassic basins;
(3) a Triassic-Jurassic facies found in Late Jurassic-Early Cretaceous basins; and
(4) a Jurassic-Early Cretaceous facies found in Cretaceous marginal basins.
These “facies” reveal the influence of a dynamic interplay of orogenic (mountain-building), erosional, and sediment-transport systems (such as wind and water) on sediment provenance in the southern Cordillera. They are interpreted to record stages of basin formation during phases of the supercontinent cycle and to reflect long-term secular variation (changes in Earth’s magnetic field measured in years, decades, and centuries) in this active plate tectonic setting.
Detrital zircon facies of Cordilleran terrranes in western North America
Todd A. LaMaskin, Dept. of Geography and Geology, University of North Carolina–Wilmington, 601 South College Road, Wilmington, North Carolina 28403-5944, USA; doi: 10.1130/GSATG142A.1.
GSA Today is The Geological Society of America’s science and news magazine for members and other earth scientists. Refereed lead science articles present exciting new research or synthesize important issues in a format understandable to all in the earth science community. GSA Today often features a refereed “Groundwork” article – tightly focused papers on issues of import to earth science policy, planning, funding, or education. All GSA Today articles are open access at www.geosociety.org/pubs/.
Media Contact
More Information:
http://www.geosociety.orgAll latest news from the category: Earth Sciences
Earth Sciences (also referred to as Geosciences), which deals with basic issues surrounding our planet, plays a vital role in the area of energy and raw materials supply.
Earth Sciences comprises subjects such as geology, geography, geological informatics, paleontology, mineralogy, petrography, crystallography, geophysics, geodesy, glaciology, cartography, photogrammetry, meteorology and seismology, early-warning systems, earthquake research and polar research.
Newest articles
Superradiant atoms could push the boundaries of how precisely time can be measured
Superradiant atoms can help us measure time more precisely than ever. In a new study, researchers from the University of Copenhagen present a new method for measuring the time interval,…
Ion thermoelectric conversion devices for near room temperature
The electrode sheet of the thermoelectric device consists of ionic hydrogel, which is sandwiched between the electrodes to form, and the Prussian blue on the electrode undergoes a redox reaction…
Zap Energy achieves 37-million-degree temperatures in a compact device
New publication reports record electron temperatures for a small-scale, sheared-flow-stabilized Z-pinch fusion device. In the nine decades since humans first produced fusion reactions, only a few fusion technologies have demonstrated…