Jurassic titaniferous ironstone in a Devonian host: Pivot Coal Measures expunged

1995 ◽  
Vol 7 (3) ◽  
pp. 293-301 ◽  
Author(s):  
Ken J. Woolfe ◽  
Malcolm J. Arnot ◽  
Graham M. Bradley
Keyword(s):  
Thin Section ◽  
Sedimentary Rocks ◽  
Carbonaceous Shale ◽  
Conchoidal Fracture ◽  
Sedimentary Structures ◽  
Victoria Land ◽  
Thin Section Petrography ◽  
Coal Measures

The Devonian, Pivot Coal Measures in southern Victoria Land are non-carbonaceous. The sequence contains bedding parallel, titaniferous ironstones up to 50 cm thick, but no coal or carbonaceous shale, the unit is consequently renamed Pivot Member of the Arena Sandstone. The more Fe-Ti oxide-rich (up to 40 modal %) beds appear black and coal-like with conchoidal fracture and closely spaced cleat-like fractures. The coal-like beds grade laterally and vertically into less altered sedimentary rocks in which fine bedding-parallel concentrations of Fe-Ti oxide pick-out parting surfaces on ripples and other sedimentary structures. Thin section petrography shows that the Fe-Ti oxide is replacive, and outcrop relationships show that the replacement was related to dolerite intrusion 200 million years after the sedimentary host was deposited. Replacement of muscovite, biotite and chlorite by Fe-Ti-oxide occurred at 179 ± 3 Ma, at pressures of 0.3–0.4 kbar and at temperatures as low as 380°C.

PRODUCTION AND SUPPLY OF CERAMIC OIL LAMPS IN HELLENISTIC AND EARLY ROMAN NEA PAPHOS, CYPRUS: INTEGRATED TYPOLOGICAL, CHRONOLOGICAL AND PROVENANCE STUDIES

2021 ◽  
pp. 1-67
Author(s):  
Małgorzata Kajzer ◽  
Edyta Marzec ◽  
Evangelia Kiriatzi ◽  
Noémi S. Müller
Keyword(s):  
Urban Development ◽  
Thin Section ◽  
Local Production ◽  
Provenance Studies ◽  
Political Transformations ◽  
Manufacturing Techniques ◽  
Thin Section Petrography ◽  
The Impact ◽  
Xrf Spectroscopy

This paper presents the results of a multipronged approach to the study of the Hellenistic and Early Roman ceramic oil lamps excavated at the Agora of Nea Paphos in Cyprus. The assemblage was studied macroscopically, and selected samples were analysed through WD-XRF spectroscopy and thin section petrography, combined with refiring tests. The integrated results revealed that local production changed through time in terms of lamp shapes, manufacturing techniques and clay recipes, while imported lamps originated from a range of sources. The transformations seen in the local production correlate with changes in the origin of imported lamp supply and the impact of other centres on the local lamp manufacture. These patterns in production and supply could be most likely associated with political transformations and urban development.

scholarly journals Sedimentology and Economic Significance of Hangu Formation, Northwest Pakistan

2020 ◽  
Vol 11 (1) ◽  
pp. 48-55
Author(s):  
Kamil Ahmed Qureshi ◽  
Muhammad Raza Shah ◽  
Ishaque Ali Meerani ◽  
Shah Fahad ◽  
Hamid Hussain ◽  
...  
Keyword(s):  
Coal Seam ◽  
Carbon Content ◽  
Calorific Value ◽  
Chemical Study ◽  
Ash Content ◽  
Coarse Grained ◽  
Carbonaceous Shale ◽  
Sedimentary Structures ◽  
Economic Significance ◽  
Quartz Arenite

The Hangu Formation (Paleocene) consists of sandstone, siltstone, carbonaceous shale, coal and laterite. It is well exposed in the Trans Indus Surghar range and the southern Hazara basin. The sandstone is yellowish brown, fine to coarse grained and medium to thick bedded. The sandstone of the Hangu Formation is classified as quartz arenite on the Q-F-L diagram. It is mostly grain supported and are cemented by silica cement. The study of different stratigraphic sections reveal that Hangu Formation can be sub-divided into a number of lithofacies on the basis of sedimentary structures and lithological variations. These include lateritic lithofacies, coal and carbonaceous shale, cross-bedded sandstone, bioclastic limestone and bioturbated sandstone. All these lithofacies are well-developed in the Baroch Nala section of the Surghar range except the lateritic lithofacies which contains a thin bed of ferruginous clay. In the studied sections of the Hazara basin, the lateritic lithofacies is the only well-developed lithofacies present in the area. The coal occurs at two stratigraphic levels in the Baroch Nala section. The lower coal seam is thick and its chemical study indicates higher calorific value and carbon content than the upper coal seam and with low moisture/ash content. On the basis of the calorific value, the coal of the Hangu Formation is characterized as high volatile bituminous. The degree of laterization is strong in the Langrial and Khanpur sections and moderate in Baroch Nala section.

An early actinopterygian ichthyofauna from the Scottish Lower Coal Measures Formation: Westphalian A (Bashkirian)

2016 ◽  
Vol 107 (4) ◽  
pp. 351-394
Author(s):  
Francis M. Elliott
Keyword(s):  
Morphological Characteristics ◽  
Carbonaceous Shale ◽  
Additional Information ◽  
Skull Roof ◽  
Coal Measures ◽  
Skull Bones

ABSTRACTTen new early actinopterygian taxa are described from material collected from five North Lanarkshire coal shale tips in the Midland Valley of Scotland. The newly described taxa include Rhadinichthys? ornatocephalum, Rhadinichthys glabrolepis, Pseudogonatodus aurulentum, Pseudohaplolepis argentatum, Rhadinichthys? plumosum and Lanarkichthys gardineri. Also included are the haplolepids Blairolepis wallacei, Parahaplolepis poppaea, Braccohaplolepis fenestratum and Andrewsolepis lochlani. Additional information was also obtained for a further two named species, Rhadinichthys monensis Egerton and Rhadinichthys grossarti Traquair. The material used for this study was obtained from finely laminated slabs of carbonaceous shale containing incomplete and disarticulated specimens, including isolated skull dermal elements and scales preserved en masse. Using this information, the dermal skull bones of a number of taxa were reconstructed and illustrated in dorsal and lateral views. Furthermore, morphological characteristics of the skull roof of each taxon was used to obtain an appropriate dataset, in order to undertake non-vigorous phylogenic analyses to demonstrate possible relationships between the various groups within the assemblage. In addition, ossified endocranial remains from specimens of Rhadinichthys monensis were examined.

Extent of Grenvillian remanence components in rocks of the Southern Province

1982 ◽  
Vol 19 (4) ◽  
pp. 698-708 ◽  
Author(s):  
M. Stupavsky ◽  
D. T. A. Symons
Keyword(s):  
Magnetic Field ◽  
North America ◽  
Thin Section ◽  
Sedimentary Rocks ◽  
Pole Position ◽  
River Valley ◽  
Field Reversal ◽  
Paleomagnetic Study ◽  
Northern Portion ◽  
Sediment Matrix

Early Aphebian Gowganda sedimentary rocks and intruding Nipissing diabase sills were sampled for paleomagnetic study at 88 sites (~500 cores, ~1000 specimens) along two ~42 km long profiles extending north from the Grenville Front into the Cobalt Plate of the Southern Structural Province in the River Valley – Lake Temagami area of Ontario. After AF demagnetization a postfolding pre-Nipissing ~2200 Ma remanence was found in eight of the 37 Gowganda sediment sites that were > 2 km north of the front, giving a pole at 109°W, 63°N (dp = 10°, dm = 19°). The Nippissing diabase from > 2 km north of the front retains a stable antiparallel prefolding N1 remanence direction in 22 of 40 sites, giving a pole position of 85°W, 17°S (dp = 6°, dm = 10°). These "south and down" remanence directions found in the southern portion of the plate contrast with the antiparallel "north and up" directions found in the northern portion, thereby indicating the occurrence of either two nearly cogenetic Nipissing intrusive events or the sequential emplacement of the Nipissing during an Earth's magnetic field reversal across the plate. At two sites a Nipissing remagnetized remanence was found in Gowganda sediments with a pole of 115°W, 18°S. Also three "Nipissing" sites give a pole at 164°W, 3°N, which is close to the known pole for the later ~1.25 Ga Sudbury olivine diabase dikes. One site is adjacent to a large dike and two were found on thin-section examination to be olivine diabase. The eight sites in Gowganda sediment matrix and conglomerate clasts and in Nipissing diabase from within < 2 km from the front were found to have a postfolding metamorphic remanence with a Grenville orogenic pole at 45°W, 51°N (dp = 19°, dm = 21°). Finally, the results lead to a suggested revision in the APW path for the ~2300–~1650 Ma interval for North America.

scholarly journals Preliminary Rb-Sr age determinations from the North Greenland fold belt, Johannes V Jensen Land, with comments on the metamorphic grade

1981 ◽  
Vol 106 ◽  
pp. 77-84
Author(s):  
N Springer
Keyword(s):  
Sedimentary Rocks ◽  
Metamorphic Grade ◽  
Low Grade ◽  
Fold Belt ◽  
Isotopic Dating ◽  
Field Mapping ◽  
Sedimentary Structures ◽  
The North ◽  
North Greenland ◽  
Age Determinations

This report presents the first Rb-Sr age determinations obtained on low-grade metasediments within the eastern part of the North Greenland fold belt. Samples were collected during the 1979 field mapping in eastem Johannes V. Jensen Land, the results ofwhich have been published elsewhere (Soper et al., 1980). Material selected for this study was taken from moderately folded rocks of the Polkorridoren Group and from the northem part of the fold belt where deformation is intense and sedimentary structures are rarely preserved (fig. 23). The principles and methods of isotopic dating of sedimentary rocks applied in this study have been treated in a recent paper by Clauer (1979).

scholarly journals Formation of thrust-block moraines at the margins of dry-based glaciers, south Victoria Land, Antarctica

1996 ◽  
Vol 22 ◽  
pp. 68-74 ◽  
Author(s):  
Sean J. Fitzsimons
Keyword(s):  
Pore Water ◽  
Pore Water Pressure ◽  
Freezing Point ◽  
Water Pressure ◽  
Lacustrine Sediment ◽  
Dry Valleys ◽  
Bed Deformation ◽  
Sedimentary Structures ◽  
Victoria Land ◽  
Subglacial Meltwater

Several dry-based alpine glaciers in the Dry Valleys of south Victoria Land, Antarctica, have prominent end moraines. Examination of their morphology, structure and sedimentology shows they consist of blocks of sand, gravel and organic silt within which sedimentary structures unrelated to entrainment and transportation by ice are well preserved. The nature and preservation of sedimentary structures, together with the presence of algae mats in the sediment, suggest formation by proglacial entrainment, transportation and deposition of frozen blocks of lacustrine sediment. Previous explanations of the formation of thrust-block moraines, including those that stress the importance of elevated pore-water pressure and Weertman’s ice-debris accretion hypothesis, depend on the presence of subglacial meltwater or the 0° C isotherm being situated close to the glacier bed. These models appear inappropriate for cold, dry-based glaciers because their basal temperatures are well below freezing point and they rest on deep permafrost. Three alternative models for the formation of thrust-block moraines at the margins of dry-based glaciers are examined in this paper: block entrainment of sediment associated with frozen-bed deformation; entrainment by overriding and accretion of marginal-ice and debris aprons; and transient wet-based conditions associated with glaciers flowing into ice-marginal lakes.

Sign in / Sign up

Export Citation Format

Share Document