Core description, photographs, and core and x-ray analyses of portions of the Upper Cretaceous Mesaverde Group, Washakie Basin, Wyoming

1978 ◽  
Author(s):  
Theodore F. Tyler
Keyword(s):  
Upper Cretaceous ◽  
X Ray ◽  
Core Description ◽  
Mesaverde Group

scholarly journals Provenance and Sedimentary Context of Clay Mineralogy in an Evolving Forearc Basin, Upper Cretaceous-Paleogene and Eocene Mudstones, San Joaquin Valley, California

Minerals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 71
Author(s):  
Andrew Hurst ◽  
Michael Wilson ◽  
Antonio Grippa ◽  
Lyudmyla Wilson ◽  
Giuseppe Palladino ◽  
...  
Keyword(s):  
Phase Transitions ◽  
Upper Cretaceous ◽  
Clay Fraction ◽  
Clay Mineralogy ◽  
Bulk Rock ◽  
X Ray Diffraction ◽  
Arc Volcanism ◽  
X Ray ◽  
Magmatic Arc ◽  
Tropical Weathering

Mudstone samples from the Moreno (Upper Cretaceous-Paleocene) and Kreyenhagen (Eocene) formations are analysed using X-ray diffraction (XRD) and X-ray fluorescence (XRF) to determine their mineralogy. Smectite (Reichweite R0) is the predominant phyllosilicate present, 48% to 71.7% bulk rock mineralogy (excluding carbonate cemented and highly bio siliceous samples) and 70% to 98% of the <2 μm clay fraction. Opal CT and less so cristobalite concentrations cause the main deviations from smectite dominance. Opal A is common only in the Upper Kreyenhagen. In the <2 μm fraction, the Moreno Fm is significantly more smectite-rich than the Kreyenhagen Fm. Smectite in the Moreno Fm was derived from the alteration of volcaniclastic debris from contemporaneous rhyolitic-dacitic magmatic arc volcanism. No tuff is preserved. Smectite in the Kreyenhagen Fm was derived from intense sub-tropical weathering of granitoid-dioritic terrane during the hypothermal period in the early to mid-Eocene; the derivation from local volcanism is unlikely. All samples had chemical indices of alteration (CIA) indicative of intense weathering of source terrane. Ferriferous enrichment and the occurrence of locally common kaolinite are contributory evidence for the intensity of weathering. Low concentration (max. 7.5%) of clinoptilolite in the Lower Kreyenhagen is possibly indicative of more open marine conditions than in the Upper Kreyenhagen. There is no evidence of volumetrically significant silicate diagenesis. The main diagenetic mineralisation is restricted to low-temperature silica phase transitions.

Late Mesozoic—Cenozoic clay mineral successions of southern Iran and their palaeoclimatic implications

Clay Minerals ◽  
2005 ◽  
Vol 40 (2) ◽  
pp. 191-203 ◽  
Author(s):  
F. Khormali ◽  
A. Abtahi ◽  
H. R. Owliaie
Keyword(s):  
Electron Microscopy ◽  
Upper Cretaceous ◽  
Sedimentary Rocks ◽  
X Ray Diffraction ◽  
Humid Climate ◽  
X Ray ◽  
Late Mesozoic ◽  
Southern Iran ◽  
Transmission Electron

AbstractClay minerals of calcareous sedimentary rocks of southern Iran, part of the old Tethys area, were investigated in order to determine their origin and distribution, and to reconstruct the palaeoclimate of the area. Chemical analysis, X-ray diffraction, transmission electron microscopy, scanning electron microscopy, and thin-section studies were performed on the 16 major sedimentary rocks of the Fars and Kuhgiluyeh Boyerahmad Provinces.Kaolinite, smectite, chlorite, illite, palygorskite and illite-smectite interstratified minerals were detected in the rocks studied. The results revealed that detrital input is possibly the main source of kaolinite, smectite, chlorite and illite, whilein situneoformation during the Tertiary shallow saline and alkaline environment could be the dominant cause of palygorskite occurrences in the sedimentary rocks.The presence of a large amount of kaolinite in the Lower Cretaceous sediments and the absence or rare occurrence of chlorite, smectite, palygorskite and illite are in accordance with the warm and humid climate of that period. Smaller amounts of kaolinite and the occurrence of smectite in Upper Cretaceous sediments indicate the gradual shift from warm and humid to more seasonal climate. The occurrence of palygorskite and smectite and the disappearance of kaolinite in the late Palaeocene sediments indicate the increase in aridity which has probably continued to the present time.

scholarly journals Initial Laramide tectonism recorded by Upper Cretaceous paleoseismites in the northern Bighorn Basin, USA: Field indicators of an applied end load stress

Geology ◽  
2019 ◽  
Vol 47 (11) ◽  
pp. 1059-1063 ◽  
Author(s):  
W.T. Jackson ◽  
M.P. McKay ◽  
M.J. Bartholomew ◽  
D.T. Allison ◽  
D.L. Spurgeon ◽  
...  
Keyword(s):  
Upper Cretaceous ◽  
North American Plate ◽  
Plate Boundaries ◽  
Bighorn Basin ◽  
Group Position ◽  
Clastic Dike ◽  
Basement Deformation ◽  
Field Indicators ◽  
Sand Source ◽  
Mesaverde Group

Abstract Soft-sediment deformational structures associated with paleoseismicity (e.g., planar clastic dikes) exist within Upper Cretaceous Mesaverde Group strata in the Laramide Elk Basin anticline, northern Bighorn Basin (Wyoming, USA). Retrodeformation of the Elk Basin anticline to a horizontal Mesaverde Group position indicates that all basement offset is removed and that clastic dikes exhibit a dominant northeast trend. The trend of clastic dikes corresponds to the interpreted northeast-southwest direction of early Laramide layer-parallel shortening, suggesting that the development of clastic dikes recorded initiation of basement deformation and Laramide tectonism. To determine the timing of clastic dike development, we present zircon U-Pb geochronology from the stratigraphically lowest sand-source bed generating upwardly injected clastic dikes and a volcanic bentonite bed (Ardmore bentonite) above the stratigraphic interval containing clastic dikes. Weighted mean ages bracket clastic dike development between 82.4 and 78.0 Ma. Our results imply initiation of basement deformation ∼8–15 m.y. prior than other estimates in the Bighorn Basin. Therefore, we interpret the development of clastic dikes in the Elk Basin anticline to represent an initial phase of Laramide tectonism associated with an applied end load stress transmitted from the southwestern North American plate margin in response to the collision of the conjugate Shatsky Rise oceanic plateau ca. 90–85 Ma. Results demonstrate how sedimentary responses in the foreland can be used to understand tectonic processes at plate boundaries and provide spatial-temporal parameters for models of Laramide deformation.

Comments on a Cretaceous coprolite from Alberta, Canada

1970 ◽  
Vol 7 (3) ◽  
pp. 1008-1012 ◽  
Author(s):  
M. Waldman
Keyword(s):  
Upper Cretaceous ◽  
X Ray Diffraction ◽  
X Ray

A coprolite (N.M.C. 13565) containing remains of a gar-pike, from the Upper Cretaceous, non-marine, Oldman Formation of Alberta is believed to be that of a crocodile, although it may be possibly derived from a terrestrial carnivorous reptile of necrophagic or piscivorous habit. X-ray diffraction studies show the specimen to be composed of apatite.

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