Sentences with phrase «ages of the zircons»
«The astonishing result was that the ages of the zircons measured from all five of the smaller volcanoes extended continuously from the time of the eruption 75,000 years ago back to the last supervolcanic eruption.»
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Then they used uranium / lead dating to determine the age of each zircon (the time when its parent rock crystallized).
Not exact matches
«Our measurements, however, support some previous geochemical measurements on ancient zircons that suggest an age of 4.4 billion years.»
In addition to the radiometric dating techniques that revealed the ages of these ancient zircons, geologists used other analytical techniques to extract information about the environment in which the crystals formed, including the temperature and whether water was present.
Working with Miller and doctoral student Abraham Padilla at Vanderbilt, Joe Wooden at Stanford University, Axel Schmitt and Rita Economos from UCLA, Ilya Bindeman at the University of Oregon and Brennan Jordan at the University of South Dakota, Carley analyzed about 1,000 zircon crystals for their age and elemental and isotopic compositions.
As Guy Simpson, a researcher at UNIGE further explains: «Modelling meant that we could establish how the age of crystallised zircon in a cooled magma reservoir depends on the flow rate of injected magma and the size of the reservoir.»
Professor Luca Caricchi adds: «When we determine the age of a family of zircons from a small sample of solidified magmatic rock, using results from the mathematical model we have developed, we can tell what the size of the entire magma chamber was, as well as how fast the magma reservoir grew.»
To help narrow the range of possible ages for the sandstone, Siddoway and Gehrels compared the age distributions of the Tava zircons with the age distributions of zircons found in other sandstone formations in Colorado, Utah, northern Arizona, and southern California.
Bowring's earlier analysis of the zircons indicated they might have grown in two or more widely - spaced time periods, obscuring their exact age.
Shellnutt (2017), in a succinct review of the Panjal Traps (c. 290 Ma), an important component of the Himalayan magmatic province, discusses the synchronous nature of basalts, that chemically range from continental tholeiite to ocean - floor basalt, and crustally derived silicic volcanic rocks (rhyolites and trachytes: 206Pb / 238U zircon in situ age of 289 ± 3 Ma), that developed in a shallow lithospheric rift with significant mingling between crustal melts and mafic magmas.
Just two years ago a group had studied the likely timing of impacts on the early Earth and they suggested that these impacts might explain the ages of the ancient zircons.»
... The great distances of sediment transport and high degree of mixing of detrital zircon ages are extraordinary, and they may be attributed to a combination of widespread orogenesis associated with the assembly of Gondwana, the equatorial position of continents, potent chemical weathering, and sediment dispersal across a nonvegetated landscape.»
Careful radioactive dating shows that these zones formed essentially simultaneously, even in Hadean zircons of different ages, Mojzsis says.
• Zircon crystallization and eruption occurred coevally at Ma at DETERMINING AGE OF ROCKS AND FOSSILS FRANK K. MCKINNEY THE AGE of fossils intrigues almost everyonOF ROCKS AND FOSSILS FRANK K. MCKINNEY THE AGE of fossils intrigues almost everyonof fossils intrigues almost everyone.
The stable form of carbon is carbon 12 Molybdenite Re / Os dating, zircon U — Pb age and geochemistry of granitoids in the Yangchuling porphyry W — Mo deposit (Jiangnan tungsten ore belt), China
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2018-04-08 18:05 Molybdenite Re / Os dating, zircon U — Pb age and geochemistry of granitoids in the Yangchuling porphyry W — Mo deposit (Jiangnan tungsten ore belt), China I'm a virgin and am dating a woman who had a bad past, but is really pure now.