The tuffs are associated with subordinate sandstones and siltstones and minor lava. |
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Most sandstones arc characterized by erosional bases, hummocky cross-stratification and intensely burrowed tops. |
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Carrier-bed rocks are lithologically the same as reservoir rocks, that is, sandstones, limestones, or fractured rocks of all types. |
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It is thus unlikely that the bulk of the Carboniferous detritus could have been derived by recycling of preexisting Silurian sandstones. |
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It consists of phyllites, calcareous sandstones and limestone conglomerates that are boudinaged and folded. |
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The cross-bedded sandstones represent dunes from the dry intervals, when plant and animal life was less abundant. |
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Molasse is a dialect word used by French-speaking farmers in western Switzerland to describe soft, friable sandstones. |
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It contains over 50 chest beds which are interbedded with shales, carbonaceous sandstones and minor tuffs. |
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Does lithology account for the very different patterns of faulting in the Permian sandstones and dolostones? |
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The upper 300 m of the Haengefjeldet Formation is made up of 3-10 m thick well-sorted, normally graded, matrix-supported sandstones and wackes. |
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Among the 30 different types of stone recognized are varieties of diorite, granite, bedded tuff, sandstones, limestones, and tufa. |
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The most resistant rocks are quartzite and quartz-rich sandstones, and tough fine-grained rocks such as slate. |
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This member grades upwards into greenish mudstones and greenish-yellow, fine-grained sandstones of the overlying Cuarcitas Azules Member. |
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Whilst the greater part was just ordinary stone, many decorative elements were carved out of freestone such as sandstones and limestone. |
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Those sections expose concretionary mudstones interbedded with thinner quartz sandstones, limestones, and marl. |
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The significance of the contemporaneous, but kinematically very different fault sets in the sandstones requires explanation. |
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Occasional thin dark grey laminated mudstones are associated with some of the sandstones. |
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A comparison between all the techniques used to analyse calcite cements reveals subtle differences between injected and depositional sandstones. |
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Locally, near the village of Timirovo, the limestones are intercalated with arkosic sandstones. |
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They are interbedded with bioturbated muddy and sandy limestones, quartz-skeletal siltstones and sandstones. |
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The rocks typically comprise a monotonous sequence of greywackes, reddish-weathering arkosic sandstones, shales and subordinate conglomerates. |
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They are typically produced from limestone, crystalline rocks, and sandstones. |
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The overburden comprises sands and shales with thin coal interbeds, which passes upwards into sandstones and shales without coals. |
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In East Falkland, pebbly sandstones have been interpreted as subaqueous debris flows. |
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By contrast, the large, structureless, fossil-rich sandstones were formed by debris flows from huge, nonmigrating dunes. |
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Intra-sedimentary faults, palaeochannels, and cross-bedding in sandstones and conglomerates are locally abundant. |
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The limestone changes from conchiferous sandstones to consolidated coquina limestone. |
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The formation is composed of shales, mudstones, sandstones, oil shales and coal beds accumulated in fluvial to lacustrine environments. |
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It was intruded into a succession of thinly bedded sandstones and carbonaceous silt and mudstones. |
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The rocks have been intensely deformed and sheared and the calcareous conglomeratic sandstones are well indurated. |
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Thick shale packages, approaching 30 m thick, occur interbedded with the turbidite sandstones. |
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These beds are commonly channelized and always exhibit erosive bases incised into underlying fine-grained turbiditic sandstones. |
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Near the top of the succession blue-grey silty calcareous mudstones are interbedded with subordinate graded sandstones. |
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That unconformity is overlain by sandstones of the Puentelles Formation, dated as late Kasimovian based on its fossil flora. |
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The sandstones show variable grading, with planar, rippled and undulatory lamination. |
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These sandstones represent the youngest of the Corallian sequences identified in this study. |
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On its south side the Oytag arc is thrust over Carboniferous sandstones and limestones that are folded into spectacular nappes. |
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The Rocks of Belogradchik are formed of versicoloured Triassic sandstones and conglomerates. |
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Previous workers have attributed these differences to changes in rheology, i.e. brittle faulting in sandstones v. more ductile folding and faulting in dolostones. |
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Two endmember scenarios are defined as possible models to explain the different mineral-chemical stratigraphical styles shown by turbidite sandstones. |
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The Brushy Basin shales, mudstones, and sandstones were deposited by a series of rivers and streams originating from the west and containing large volumes of volcanic ash. |
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The Annascaul Formation is at least 500 m thick, and is dominated by mudrocks with subordinate quartz wacke sandstones, tuffaceous fine conglomerates and melange. |
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The upper part is more sandy, containing clean, arkosic, sharp-based sandstones up to 50 cm thick with locally matrix-supported conglomeratic bases. |
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A second scenario is that quarrying operations exposed easily weathered fossiliferous shales, mudstones, or fine-grained sandstones interbedded with limestones. |
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Mudstones are the main source of oil and gas, although by the time the oil or gas is extracted it has usually migrated to porous rocks such as sandstones of limestones. |
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More specifically, the western part of the county is composed mainly of Devonian and Mississippian sandstones and shales with some Silurian and Ordovician rocks present. |
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The first cycle initiated in the early Paleocene and represents a transition from Cretaceous marine turbidites and shales to subaerial fluvial sandstones and conglomerates. |
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The Fossil Bluff Group consists of fossiliferous, shallow marine to sub-aerial fluviatile sandstones and conglomerates of probable fore-arc origin. |
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The formation is composed of red siltstones, containing discontinuous calcrete horizons, channelized sandstones and thin beds of current-rippled fine sandstone. |
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Well-rounded clasts include lava, volcaniclastic sandstones and bioclastic limestones with nummulites, bryozoa, microbial carbonate and bivalve material. |
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In the argillaceous fraction of a sedimentary series of petroliferous sandstones from the Sahara two successive diagenetic changes are considered. |
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Permian shelf-type successions there pass into Triassic sandstones and shales with detached Permian limestone blocks, overlain by Upper Triassic neritic carbonates. |
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The thinner bedded sandstones are considered overbank flood deposits. |
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Previous studies have shown that the oldest Palaeozoic unit included fluvial conglomerates and conglomeratic sandstones. |
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All the rocks found on the island are sedimentary, such as limestones, mudstones and sandstones. |
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Red sandstones are also seen in the Southwest and West of Britain, as well as central Europe and Mongolia. |
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Therefore, there have been many published ways to classify sandstones, all of which are similar in their general format. |
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The southern edge of the dome is overlain by sandstones of Triassic age though these barely impinge upon the National Park. |
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The rocks of the central part of the anticline include hard sandstones, and these form hills now called the High Weald. |
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The peripheral areas are mostly of softer sandstones and clays and form a gentler rolling landscape, the Low Weald. |
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Many important fossils have been found in the sandstones and clays of the Weald, including, for example, Baryonyx. |
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During the Precambrian, the Torridonian sandstones and the Moine were also laid down. |
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Large aeolian sand dunes are preserved in Permian sandstones near Brodick, showing the presence of an ancient desert. |
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The Clwydian Hills are formed from an upstanding block of Silurian age sandstones, mudstones and siltstones. |
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Close to Hereford, the geology of the area around the village of Woolhope is largely made up of Silurian limestones, shales and sandstones. |
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To the south of this, the Herefordshire lowlands are largely underlain by red mudstones and sandstones, producing a redder soil. |
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The Triassic continental interior climate was generally hot and dry, so that typical deposits are red bed sandstones and evaporites. |
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The rock is easily quarried and some of the yellow sandstones from Fersness were used in the construction of St Magnus Cathedral in Kirkwall. |
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The rocks consist of sandstones, shales, siltstones and clays formed in the Miocene and uplifted in the Pleistocene. |
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The caves are enlarged out of Lower Permian sandstones and their associated breccias and purple shales. |
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Siltstones differ significantly from sandstones due to their smaller pores and higher propensity for containing a significant clay fraction. |
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The underlying geology is the Millstone Grit series with sandstones and coarse gritstones separated by bands of shale. |
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The southern edge of the dome is overlain by sandstones of Triassic age though they barely impinge on the National Park. |
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These are overlaid by sandstones and limestones in the west and clay in the east. |
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The group comprises a succession of sandstones, mudstones and siltstones, the specifics of the sequence varying from one area to another. |
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The Millstone Grit Group comprises over thirty individually named sandstones, some of regional extent, others more local in their occurrence. |
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Some of the sandstones serve as aquifers into which numerous wells and boreholes have been sunk to provide local water supplies. |
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Coarse sandstones in the area are known as Addingham Edge and Bramhope Grits. |
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At Great Dib Wood the Otley Shell Bed is sandwiched between two Namurian sandstones. |
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Inner and southern areas of Leeds lie on a layer of coal measure sandstones forming the Yorkshire Coalfield. |
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The sampled sandstones are light grey, very fine-grained, weakly cemented arenite, mostly dominated by quartz grains. |
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The lower boundary of the unit coincides with a sharp change from sandstones to argillites. |
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The aquifer is composed of arkosic sandstones containing siltstone and shaly layers. |
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Shaly sandstones with poor reservoir quality however with high gas readings were encountered in the Late Cretaceous Shetland Group. |
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In red and green siltstones, and in sandstones of the Upper Triassic estimated to be 200 million years old, they found an abundance of fossils. |
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The Fms are unusual in that many of them are periglacial sandstones often sealed by glacial tillites. |
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In addition, nanobacteria may be important in clay mineral diagenesis in buried sandstones. |
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The Sarmatian sandstones and sands in the interfluve of Kura and Iori are stained with oil. |
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The sandstones are considered to be derived from Devonian Old Red Sandstone in the Munster basin on the Irish mainland. |
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Within the overlying sediments strong clay alteration is widespread and affects pelites, sandstones and conglomerates. |
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Eolian sandstones in Upper Triassic-Lower Jurassic red beds of the Fundy Basin, Nova Scotia. |
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Relationships between open-water intervals and floodplain deposits cannot be determined where open-water units are erosionally overlain by multistorey sandstones. |
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Devonian conglomerates composed of sandstones and pelites appear in the area, and Carboniferous marine formations are unconformably overlain in sequence. |
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These deposits are commonly punctuated by metre-scale fining-upward, medium-grained, cross-bedded sandstones, interpreted as terminal distributary channels. |
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Obviously, the Vendian Formation sandstones themselves as stratiform Ba-rich sediments are the main source of barium in the groundwater of the Cambrian-Vendian aquifer system. |
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Many Fms are periglacial sandstones sealed by glacial tillites. |
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It features a 3,000ft succession of sandstones, mudstones and siltstones. |
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Rocks in the lower part consist in general of mauve sandstones, siltstones and greyly green siltstones interbedded with a few intercalated mud boulder horizons. |
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Thinly bedded pea gravel consisting of black chert and metaquartzite clasts are commonly associated with indurated sandstones and orthoquartzites. |
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It is lithologically represented by brownish-gray clays with jarosite tarnish and inter-layers of gray, fine-grained sandstones, and by marlaceous and sideritic concretions. |
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This is in an area covered by Thelon sandstones near the flank of a north-south trending basement horst of Paleoproterozoic Hurwitz Group quartzites. |
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Crossbedding in the gray sandstones shows that it is now right side up, and in Flagstaff time it was therefore on the east flank of a steply folded anticline. |
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These include the Sherwood sandstones that occur beneath much of eastern Nottinghamshire, the Permian Lower Magnesian limestone and the carboniferous limestone in Derbyshire. |
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Underlying the upper reaches of the Trent, are formations of Millstone Grit and Carboniferous Coal Measures which include layers of sandstones, marls and coal seams. |
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Within England and Wales, the entire limestone succession, which includes subordinate mudstones and some thin sandstones, is known as the Carboniferous Limestone Supergroup. |
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The predominant rocks on Bowfell are the volcaniclastic sandstones of the Seathwaite Fell Formation, with interbeds of andesite outcropping near the summit. |
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The northern crags expose some granophyric granite of the Ennerdale Intrusion, together with the bedded breccias, sandstones and tuffs of the Round How Member. |
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The Upper Peninsula exhibits Lower Silurian sandstones, limestones, copper and iron bearing rocks, corresponding to the Huronian system of Canada. |
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West Antarctica was partially in the Northern Hemisphere, and during this period large amounts of sandstones, limestones and shales were deposited. |
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In carbonate based rocks such as limestone or chalk, chert or flint concretions are common, while terrestrial sandstones can have iron concretions. |
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The Eday Group is the name for a substantial sequence of sandstones that is found at many locations in Orkney, for which Eday and the area around Eday Sound are the type area. |
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These include sandstones, greensands, oolitic limestone of the Cotswold Hills, corallian limestone of the Vale of White Horse and the Isle of Portland. |
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Younger still are the sandstones, shales and coal deposits found on the eastern flank of Derbyshire, forming the Coal Measures, which are of Westphalian age. |
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The oldest rocks occur in the northern, more upland half of the county, and are mostly of Carboniferous age, comprising limestones, gritstones, sandstones and shales. |
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Some sandstones are resistant to weathering, yet are easy to work. |
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These minerals make up the framework components of the sandstones. |
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