Compactional deformation bands in Wingate Sandstone; additional evidence of an impact origin for Upheaval Dome, Utah

2007 ◽  
Vol 256 (1-2) ◽  
pp. 169-181 ◽  
Author(s):  
C OKUBO ◽  
R SCHULTZ
2017 ◽  
Vol 4 ◽  
pp. 99-180 ◽  
Author(s):  
Jeffrey W. Martz ◽  
James I. Kirkland ◽  
Andrew R.C. Milner ◽  
William G. Parker ◽  
Vincent L. Santucci

The Chinle Formation and the lower part of the overlying Wingate Sandstone and Moenave Formation were deposited in fluvial, lacustrine, paludal, and eolian environments during the Norian and Rhaetian stages of the Late Triassic (~230 to 201.3 Ma), during which time the climate shifted from subtropical to increasingly arid. In southern Utah, the Shinarump Member was largely confined to pre-Chinle paleovalleys and usually overprinted by mottled strata. From southeastern to southwestern Utah, the lower members of the Chinle Formation (Cameron Member and correlative Monitor Butte Member) thicken dramatically whereas the upper members of the Chinle Formation (the Moss Back, Petrified Forest, Owl Rock, and Church Rock Members) become erosionally truncated; south of Moab, the Kane Springs beds are laterally correlative with the Owl Rock Member and uppermost Petrified Forest Member. Prior to the erosional truncation of the upper members, the Chinle Formation was probably thickest in a southeast to northwest trend between Petrified Forest National Park and the Zion National Park, and thinned to the northeast due to the lower Chinle Formation lensing out against the flanks of the Ancestral Rocky Mountains, where the thickness of the Chinle is largely controlled by syndepositional salt tectonism. The Gartra and Stanaker Members of the Ankareh Formation are poorly understood Chinle Formation correlatives north of the San Rafael Swell. Osteichthyan fish, metoposaurid temnospondyls, phytosaurids, and crocodylomorphs are known throughout the Chinle Formation, although most remains are fragmentary. In the Cameron and Monitor Butte Members, metoposaurids are abundant and non-pseudopalatine phytosaurs are known, as is excellent material of the paracrocodylomorph Poposaurus; fragmentary specimens of the aetosaurs Calyptosuchus, Desmatosuchus, and indeterminate paratypothoracisins were probably also recovered from these beds. Osteichthyans, pseudopalatine phytosaurs, and the aetosaur Typothorax are especially abundant in the Kane Springs beds and Church Rock Member of Lisbon Valley, and Typothorax is also known from the Petrified Forest Member in Capitol Reef National Park. Procolophonids, doswelliids, and dinosaurs are known but extremely rare in the Chinle Formation of Utah. Body fossils and tracks of osteichthyans, therapsids, crocodylomorphs, and theropods are well known from the lowermost Wingate Sandstone and Moenave Formation, especially from the St. George Dinosaur Discovery Site at Johnson Farm.


1917 ◽  
Vol 84 (2167supp) ◽  
pp. 20-22
Author(s):  
Donald Putnam Beard
Keyword(s):  

2002 ◽  
Vol 82 (16) ◽  
pp. 3129-3147 ◽  
Author(s):  
S. X. Li ◽  
X. W. Li ◽  
Z. F. Zhang ◽  
Z. G. Wang ◽  
K. Lu

2011 ◽  
Vol 704-705 ◽  
pp. 903-906
Author(s):  
Yun Li Feng ◽  
Shao Qiang Yuan ◽  
Meng Song

The microstructure evolution of a medium-carbon Si-Mn steel during deformation of undercooled austenite at different degree of deformation, temperatures and strain rates has been investigated by means of a hot compression simulation test, metallographic microscope, scanning electron microscope and transmission electron microscopy. Also, the mechanism of carbide spheroidized during deformed process has been discussed. The experiment results demonstrate that the process of evolution experienced three stages: that is, strain-induced transformation, austenite eutectoid decomposed to carbides and ferrite matrix, and spheroidization of pearlite at the range of A3-Ar3. The austenitic grains would be refined for the extra-product of ferrite above the Ar3. The eutectoid reaction was induced on the grain boundaries of ferrite and non-transformed austenite and deformation bands with the increasing volume of deformation. An optimum combination of deformation temperature and strain rate is important to obtian the dulplex microstructure consisting of ultrafine ferrites and dispersed carbide particles. The fine spheroidized microstructures are obtained while the deformed temperature reaches 650°C with ≥1.0, meanwhile, The carbides precipate in globular and shot-rod shapes. Keywords: Medium-carbon Si-Mn steel, Undercooled austentite, Microstructure evolution, Deformation induced transformation, Carbide spheroidization


1972 ◽  
Vol 25 (7) ◽  
pp. 1411 ◽  
Author(s):  
LE Lyons ◽  
LJ Warren

The low-temperature fluorescence spectrum of purified vapour-grown anthracene single crystals is presented and the free-exciton emission distinguished from a number of defect or impurity bands present even in the purest crystals. In assigning the observed bands the symmetry of the active vibrations and the origin of background fluorescence and deformation bands are discussed. The phonon structure in the region of the fluorescence origin was found to be almost completely b-polarized. Emission of electronic origin (25103 cm-1) was too weak to be observed. Polarization ratios of the principal vibronio bands at 5.6 K are given.


2021 ◽  
pp. 109960
Author(s):  
Qinmeng Luan ◽  
Jianglong Wang ◽  
Yan Huang ◽  
Daniel S Balint ◽  
Jun Jiang

2003 ◽  
Vol 38 (3) ◽  
pp. 445-455 ◽  
Author(s):  
Donald S. STONE ◽  
Ann M. THERRIAULT
Keyword(s):  

Metals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 605
Author(s):  
Franco Lizzi ◽  
Kashyap Pradeep ◽  
Aleksandar Stanojevic ◽  
Silvana Sommadossi ◽  
Maria Cecilia Poletti

Inconel®718 is a well-known nickel-based super-alloy used for high-temperature applications after thermomechanical processes followed by heat treatments. This work describes the evolution of the microstructure and the stresses during hot deformation of a prototype alloy named IN718WP produced by powder metallurgy with similar chemical composition to the matrix of Inconel®718. Compression tests were performed by the thermomechanical simulator Gleeble®3800 in a temperature range from 900 to 1025 °C, and strain rates scaled from 0.001 to 10 s−1. Flow curves of IN718WP showed similar features to those of Inconel®718. The relative stress softening of the IN718WP was comparable to standard alloy Inconel®718 for the highest strain rates. Large stress softening at low strain rates may be related to two phenomena: the fast recrystallization rate, and the coarsening of micropores driven by diffusion. Dynamic recrystallization grade and grain size were quantified using metallography. The recrystallization grade increased as the strain rate decreased, although showed less dependency on the temperature. Dynamic recrystallization occurred after the formation of deformation bands at strain rates above 0.1 s−1 and after the formation of subgrains when deforming at low strain rates. Recrystallized grains had a large number of sigma 3 boundaries, and their percentage increased with strain rate and temperature. The calculated apparent activation energy and strain rate exponent value were similar to those found for Inconel®718 when deforming above the solvus temperature.


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