WebDec 27, 2024 · Zircons recovered from a tuff within the uppermost Walcott Member of the Kwagunt Formation yield a weighted mean 206 Pb-238 U age of 729.0 ± 0.9 Ma (mean square of weighted deviates [MSWD] = 0.86), differing significantly from the previous air-abrasion upper-intercept age of 742 ± 6 Ma on zircons from this same horizon. WebThe Chuar Group (~1600 m thick) preserves a record of exten-sional tectonism, ocean-chemistry fluctuations, and biological diversi-fication during the late Neoproterozoic Era. An ash layer from the top of the section has a U-Pb zircon age of 742 ± 6 Ma. The Chuar Group was deposited at low latitudes during extension on the north-trending
Grand Canyon Rock Layers - BobsPixels
WebJan 1, 1994 · The age of the Grand Canyon orogeny is estimated at about 830 m.y., inferred from an evaluation of maximum and minimum reset K-Ar ages reported for the 1,100-m.y.-old Cardenas Lavas of the Unkar Group. ... By analogy, strata of the Chuar Group below the Sixtymile Formation are correlated with strata of the upper part of the Belt … WebThe Chuar Group (similar to 1.600 m thick) preserves a record of extensional tectonism, ocean-chemistry fluctuations, and biological diversification during the late Neoproterozoic Era. An ash... dallas tv show first episode
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WebMay 24, 2009 · Here we present palaeontological data from the >742±6-Myr-old Chuar Group from Arizona, which indicate that the biotic turnover occurred before the first low-latitude (Sturtian) glaciation,... WebSynthesis of the 780-740 Ma Chuar Group, Uinta Mountain Group, and Pahrump (ChUMP) groups, western USA: Implications for Laurentia-wide cratonic marine basins. Geological Society of America Bulletin 129: 607-624. doi: 10.1130/B31532.1 Porter, S.M. 2016. WebThe Yoruba region was invaded in the 19th century by another ethnic group, the Fulani, who pushed them south into the regions they occupy today. In the early 20th century, … dallas tv show episode guide