Lithologic studies of fine-grained Upper Cretaceous sedimentary rocks of the Black Hills region: Section A in Shorter contributions to general geology, 1930

1931 ◽  
pp. 1-54 ◽  
Author(s):  
W.W. Rubey
Keyword(s):  
Upper Cretaceous ◽  
Sedimentary Rocks ◽  
Black Hills ◽  
Fine Grained ◽  
General Geology

scholarly journals The Middle Cenomanian basal series of Planinica, Western Serbia

2002 ◽  
pp. 13-43 ◽  
Author(s):  
Dragoman Rabrenovic ◽  
Nebojsa Vasic ◽  
Jovanka Mitrovic-Petrovic ◽  
Vladan Radulovic ◽  
Barbara Radulovic ◽  
...  
Keyword(s):  
New Taxa ◽  
Upper Cretaceous ◽  
Sedimentary Rocks ◽  
Structural Features ◽  
Upper Miocene ◽  
Fine Grained ◽  
The Village ◽  
Marly Limestone

Sedimentary rocks of the Upper Cretaceous basal series found at the village of Planinica, Western Serbia, are composed of thick coarse clastics and beds and intercalations of medium- to fine-grained clastics. The series lies transgressively over Jurassic serpentinite and peridotite, and under Upper Miocene marlstone and marly limestone. Sedimentary, petrographic, paleontological, and biostratigraphic characteristics of the basal series are described and its lithological members and their structural features are identified. From medium-grained sandy matrix in thick coarse clastics, two ammonite taxa, four brachiopod taxa (including the new taxa Orbirhynchia oweni and "Terebratula" n. gen. et sp.), and eleven echinoid taxa are described. The brachiopod species Kingena concinna Owen is used in dating the basal series as Middle Cenomanian, whereas limestone fragments in coarse clastics correspond to the Late Albian and Early Cenomanian.

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 High-frequency sea-level changes recorded in deep-water carbonates of the Upper Cretaceous Dol Formation (island of Brač, Croatia)

2010 ◽  
Vol 61 (1) ◽  
pp. 29-38
Author(s):  
Damir Bucković ◽  
Maja Martinuš ◽  
Duje Kukoč ◽  
Blanka Tešović ◽  
Ivan Gušić
Keyword(s):  
Sea Level ◽  
Deep Water ◽  
High Frequency ◽  
Upper Cretaceous ◽  
Distal Part ◽  
Preferential Orientation ◽  
Sea Level Changes ◽  
Carbonate Production ◽  
Fine Grained ◽  
Platform Margin

High-frequency sea-level changes recorded in deep-water carbonates of the Upper Cretaceous Dol Formation (island of Brač, Croatia)The upper part of the Middle Coniacian/Santonian-Middle Campanian deep-water Dol Formation of the island of Brač is composed of countless fine-grained allodapic intercalations deposited in an intraplatform trough. Within the studied section 13 beds can be distinguished, each defined by its lower part built up of dark grey limestone with abundance of branched, horizontally to subhorizontally oriented burrows, and the upper part, in which the light grey to white limestone contains larger burrows, rarely branched, showing no preferential orientation. The lower, dark grey, intensively bioturbated levels are interpreted as intervals formed during high-frequency sea-level highstands, while the upper, light grey-to-white levels are interpreted as intervals formed during the high-frequency sea-level lowstands. Cyclic alternation of these two intervals within the fine-grained allodapic beds is interpreted as the interaction between the amount of carbonate production on the platform margin and the periodicity and intensity of shedding and deposition in the distal part of toe-of-slope environment, which is governed by Milankovitch-band high frequency sea-level changes.

scholarly journals Exsolution Lamellae in Orthopyroxene of Lherzolite from the Pauza Ultramafic Rocks, Ne Iraq: Evidence of Deep Mantle Signature in the Zagros Suture Zone

2013 ◽  
Vol 2 (9) ◽  
pp. 102-115
Author(s):  
Yousif Osman Mohammad ◽  
Nabaz Rashid Hama Aziz
Keyword(s):  
High Pressure ◽  
Upper Cretaceous ◽  
Suture Zone ◽  
Ultramafic Rocks ◽  
Chromian Spinel ◽  
Spinel Peridotite ◽  
Incongruent Melting ◽  
Fine Grained ◽  
Ultra High Pressure ◽  
Deep Mantle

The Pauza ultramafic body is part of Upper Cretaceous Ophiolitic massifs of the Zagros Suture Zone, NE Iraq. The present study reveals evidence of Ultra-high pressure (UHP), and deep mantle signature of these peridotites in the Zagros Suture Zone throughout the observation of backscattered images and micro analyses which have been performed on orthopyroxen crystals in lherzolite of Pauza ultramafic rocks.Theorthopyroxen shows abundant exsolution lamellae of coarse unevenly distributed clinopyroxene coupled with the submicron uniformly distributed needles of Cr-spinel. The observed clusters of Opx–Cpx–Spl represent the decompression products of pyrope-rich garnet produced as a result of the transition from ultra-high pressure garnet peridotite to low-pressure spinel peridotite (LP). Neoblastic olivine (Fo92 – 93) with abundant multi-form Cr- spinel inclusions occurs as a fine-grained aggregate around orthopyroxene, whereas coarse olivine (Fo90-91) free from chromian-spinel is found in matrix. The similarity of the Cr-spinel lamellae orientations in both olivine and orthopyroxene, moreover, the enrichments of both Cr and Fe3+ in the Cr-spinel inclusions in neoblastic olivine relative to Cr-spinel lamellae in orthopyroxene, suggest that spinel inclusions in olivine have been derived from former Cr-spinel lamellae in orthopyroxene. Neoblastic olivine is formed by reaction of silica-poor ascending melt and orthopyroxene. It is inferred that the olivines with multi-form spinel inclusions has been formed by incongruent melting of pre-existing spinel lamellae-rich orthopyroxene.

scholarly journals Dominant Weathering Profile Assessment of Kebo-Butak Volcanic Rocks in Gedangsari and Ngawen area, Yogyakarta, Indonesia

2021 ◽  
Vol 6 (1) ◽  
Author(s):  
Fathan Hanifi Mada Mahendra ◽  
I Gde Budi Indrawan ◽  
Sugeng Sapto Surjono
Keyword(s):  
Volcanic Rocks ◽  
Sedimentary Rocks ◽  
Coarse Grained ◽  
Residual Soil ◽  
Geological Condition ◽  
Weathering Profile ◽  
Fine Grained ◽  
Degree Pattern ◽  
Weathering Degree ◽  
East West

The Gedangsari and Ngawen area is predominantly composed of volcanic and volcaniclastic sequencesdistributed east – west direction of the northern parts of Southern Mountain. The massive tectonism as well as tropical climatein this region have been producing weathering profiles in varying thickness which inevitably affects thegeotechnical properties. This study aims to assess the dominant weathering profileof the lower part of Kebo-Butak Formation as well as evaluating the distribution of the discontinuity. In order to know the dominant weathering profile and discontinuity evaluation, this study utilizes a total of  26 panels from five stations investigated through a geotechnical data acquisition including the geological condition, weathering zones, joint distribution, and discontinuity characteristics. The result shows four types of dominant weathering profiles in lower part of Kebo-Butak Formation called as dominant weathering profile A, B, C, and D. Profile A, B, C consisted of a relatively identical weathering degree pattern of fresh, slightly, moderately, completely weathered zone with the variation of thicknesses. However, the weathering degree in profile D reached the residual soil degree controlled by more intensive joints. The fine-grained sedimentary rocks also tends to have smaller spacing, shorter persistence, and higher weathering degree of discontinuities as compared to coarse-grained sedimentary rocks.

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