About 53m of Pendleian age sandstones with interlayered siltstones and some mudstone make up this formation.
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It consists of irregular volcanic blocks and rare bipolar fusiform bombs interlayered with vesicular agglutinate. A breach on the southeast side of the cone drained a central lava lake. The lava flowed southwest into the Spanish Creek valley, carrying rafts of agglutinate from the wall of the cone. Renewed volcanism on the southwestern flank of the volcano created a parasitic cone composed of loosely consolidated vesicular volcanic blocks interlayered with agglutinate.
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The rock of the mountain consists of Late Eocene-Lower Miocene sedimentary rocks from Crocker Formation which is made of sandstone, shale and interlayered sandstone-siltstone-shale unit.
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At Vesuvius it occurs as alterations from gypsum within leucite tephrite and as fumarole deposits. It occurs in dry lake beds in California and Australia. It also occurs interlayered with gypsum in caves.
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All lava flow sequences are characterized by normal polarity, except for a brief paleomagnetic reversal yielded by one lava flow and by a localized interlayered limestone in two distinct section of the High Atlas CAMP.
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They are well exposed in Mount Serteng in Guyang granite- greenstone terrane. There are three sub-units in the greenstone sequence in this terrane. The lower layer is dominated by metamorphosed mafic and ultramafic volcanic rocks, with interlayered banded iron formation.Chen, L. (2007).
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A contact metamorphic rock made of interlayered calcite and serpentine from the Precambrian of Canada. Once thought to be a pseudofossil called Eozoön canadense. Scale in mm. thumbnail Contact metamorphism is the name given to the changes that take place when magma is injected into the surrounding solid rock (country rock).
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Eozoön canadense from the Precambrian of Canada, a metamorphic rock made of interlayered calcite and serpentine. Scale in mm. Eozoön canadense (literally, "dawn animal of Canada") is a pseudofossil. John William Dawson (1865) described the banded structures of coarsely crystalline calcite and serpentine as a gigantic Foraminifera, making it the oldest known fossil.
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Felsic gneiss and granite migmatite, interlayered with supracrustal rocks and intruded by granodiorite, is intercalated in places with the supracrustal rocks of the greenstone belt. It is suggested that the likely origin for this unit is an ancient basement or earlier supracrustal succession tectonically interleaved as thrust splinters into the South Pass supracrustals.
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The Lower Siwalik is the base of the Siwalik Group. Deposition of the Lower Siwalik started in the Middle Miocene. The Lower Siwalik is characterized by alternating facies of sandstone and mudstone, deposited in fluvial and floodplain environments. Paleosol deposits are commonly interlayered with sandstone lenses on the scale of >1 m to 10 m.
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Since the 1815 eruption, the lowermost portion contains deposits of interlayered sequences of lava and pyroclastic materials. Approximately 40% of the layers are represented in the lava flows. Thick scoria beds were produced by the fragmentation of lava flows. Within the upper section, the lava is interbedded with scoria, tuffs, pyroclastic flows and pyroclastic falls.
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In their upper section (Ludlow), the shales incorporate calcareous horizons and calcareous nodules (with conodonts, nautiloids, bivalves, crinoids, and ostracods). Close to the Basque massifs, the calcareous facies changes into a detritic facies of interlayered sand– and silt–stones. The graptolite-bearing shales were later metamorphosed into lower amphibolite facies slates. They form prominent décollement surfaces.
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Olympias is a gold-rich polymetallic carbonate replacement deposit hosted in strongly deformed metamorphic rocks of the Paleozoic Kerdylia Formation of the Serbo-Macedonian Massif in northeastern Greece. The host rocks consist of biotite gneiss and schist interlayered with marble horizons, irregular pegmatite lenses and aplite. The marble horizons host the ore zones at the Olympias deposit.
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The field has a surface area of , with the shape of an ellipse. This ellipse "points" to the volcanic arc formed by the Bazman, Taftan and Koh-i- Sultan volcanic arc. The field features well preserved lava cones, associated with lava flows. The basal basaltic lava flows are interlayered with volcanic debris and more silicic lava flows.
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They are interlayered with volcanic-sedimentary rocks. They can also occur as some other features: dismembered layers, lenses and boudins. All the iron occurrences are in oxide form, rarely in silicate or carbonate form. By analysing their oxygen isotope composition, it is suggested that the iron was deposited in an environment of weakly oxidized shallow sea environment.
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The Jujols Group is less metamorphic than the mesozonal Canaveilles Group. Its sedimentation lasted probably into the lowermost Ordovician. After a longer hiatus, up to 100 m of Caradocian (Ordovician stage 5 and 6) conglomerate follow unconformably upon the Jujols Group—the Rabassa Conglomerate. This is overlain by nearly 500 m of the Cava Formation, interlayered greywackes, and shales containing volcanic horizons.
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Fixed ropes assist climbers in scrambling over this snow-covered rock band. The Yellow Band is a section of interlayered marble, phyllite, and semischist, which also requires about 100 metres of rope for traversing it. On the South Col, climbers enter the death zone. Climbers making summit bids typically can endure no more than two or three days at this altitude.
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Texturally they are wackestones grading into mudstones. They weather in a nodular and prismatic fashion and are interlayered with microcrystalline limestones rich in fine debris and bioclasts. The fossil content is dominated by rudist biostromes. The rudists are represented by Durania cornupastoris, Praeradiolites ponsi, Radiolites praesauvagesi, Radiolites radiosus, Radiolites trigeri, Biradiolites quadratus, Biradiolites angulosus, Vaccinites praepetrocoriensis, Vaccinites petrocoriensis, and Hippurites requieni var. subpolygonia.
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Specimen Ridge consists of a geological formation known as the Lamar River Formation. Within the Specimen Mountain area, it consists predominantly of an undetermined thickness of conglomerate that is interbedded with lesser proportions of tuffaceous sandstone and siltstone. Volcanic breccia is absent. The conglomerates consist of a mixture of mudflow deposits (lahars) that are complexly interlayered with braided and meandering stream deposits.
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Its fuel capacity is , giving TIV 2 an approximate range of . The body of TIV 2 is constructed of a 1/8-inch steel skin welded over a square tubing steel frame. The windows in TIV 2 are all bullet-resistant interlayered polycarbonate sheets and tempered glass. TIV 2 also features an IMAX filming turret similar to the one on the original TIV.
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Interlayered with these sandy limestones are oyster beds, iron oolite and gypsum layers; they contain ammonites like Pleydellia aalensis and Leioceras opalinum. The sequence ends with an erosional unconformity. In the southern part of the Aquitanian basin, the evaporite deposition (including layers of anhydrite) begun in the Triassic carries on right through the Lias; it reaches a thickness of up to 500 m.
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During the Triassic (Upper Norian and Rhaetian) cherty, platy limestones are deposited in the Tethyan region, an example being the Hornsteinplattenkalk of the Frauenkogel Formation in the southern Karawanks of Austria.Lein, R. et al. (1995). Neue Daten zur Geologie des Karawanken-Strassentunnels. Geol. Paläontol. Mitt. Innsbruck, 20, p. 371-387 They are composed of interlayered cherts and micrites separated by irregular, non-planar bedding surfaces.
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Both rock types enclose the same fauna as the first member. The second member likewise can change its facies to calcarenites of the beachrock type. (These calcarenites persisted near Paussac and near Toulon (Périgueux) right from the lower Angoumian onwards). The upper Angoumian closes with about 5 m (to as much as 15 m in places) of grey to yellow, platy, marly limestones interlayered with yellow marls.
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Saurosuchus hunting a group of Hyperodapedon Saurosuchus was unearthed in the Cancha de Bochas Member from the Ischigualasto Formation, being the major predator on its environment. The Ischigualasto Formation was dominated by fluvial and floodplain environments with strongly seasonal rainfalls. Interlayered volcanic ash layers above the base and below the top of the formation provide chronostratigraphic control and have yielded ages of 231.4 ± 0.3 Ma and 225.9 ± 0.9 Ma respectively.
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The La Quinta Formation is a Jurassic geologic formation which crops out in the Cordillera de Mérida and Serranía del Perijá of western Venezuela and northeastern Colombia. The formation is also present in the subsurface of the Cesar-Ranchería and Maracaibo Basins. At its type locality near La Grita, Táchira, it consists of a basal dacitic tuff followed by interlayered sandstones, tuffs, siltstones and rare limestones.Barret et al.
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The harbor is a "drowned river valley" flooded as the sea rose at the end of the last ice age. Bedrock under the harbor and in the Harborview and Calf Pasture Beach area is interlayered Ordovician trap falls gneisses and Harrison Gneiss with dark minerals hornblende, biotite and garnet. The bedrock has two folds in the harbor area. The earlier, more southerly one was formed at the same time as the Taconic Mountains.
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Ludlovian age limestone with orthocerid fossils outcrops in the upper Logar Valley. In the Dasht-i-Newar area, Silurian and Early Devonian clastic rocks grow coarser as it thickens from 650 meters of sandstone and shale to 2.2 kilometers of quartzite and conglomerate further east. Devonian rocks are limited in area, but widely dispersed containing extensive fossils. Early Devonian conglomerates with interlayered dolomite and marl outcrop in the central Afghan swell and the Hindu Kush.
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Interlayered with the slates are thin beds of dark coloured limestone and sandstone. These strata are unfossiliferous and presumed on the basis of their stratigraphic position to date to the Carboniferous Period. The slates of the Baltoro Formation is part of a thick sequence of well-cleaved black shales and slates that are exposed along almost the entire length of the Karakoram. These black shales and slates include the Singhie shales, Sarpo Laggo slate, and Pasu slates.
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The central mass of the range consists of Precambrian metamorphic rocks.2448, RAFT RIVER MOUNTAINS FAULT, Utah Geological Survey The Elba Quartzite with interlayered schist outcrops along the southern slopes of the range and in the Grouse Creek Mountains to the southwest. Cambrian quartzite outcrops in the west part of the range and in the Grouse Creek range and the Goose Creek Mountains to the west. The thinly bedded quartzites have been quarried for building stone in the area.
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Early Mississippian tuff, breccia, volcaniclastic sandstone and mafic volcanic rocks in the Skolai Group are the oldest rocks. The Skolai Group is separated from overlying Middle Triassic siltstone by a regional unconformity. Above the siltstone is the vast Nikolai Formation—basal conglomerate and basalt three kilometers thick, which extends far to the west into Alaska and as far south as Vancouver Island. It is interlayered with the Chitistone reef limestone and the deep marine McCarthy Formation.
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The Birimian rocks stretch across the countries to the north of the Gulf of Guinea, forming parallel belts that generally trend northeasterly and are wide and about apart. They consist of interlayered sedimentary and volcanic flow rocks metamorphosed to low greenschist facies. Most rivers draining the Birimian rocks hold alluvial gold deposits. They are overlaid in places by quartz-pebble conglomerates within the Tarkwaian System, name after Tarkwa, the second largest source of gold in Ghana.
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The formation consists principally of tholeiitic olivine basalt flows with interlayered beds of alluvium. The basalt is distinctive for its olivine content (typically altered to iddingsite) and its diktytaxitic texture, in which the basalt contains laths of plagioclase that are randomly oriented and have angular spaces between grains. Geologists have not reached consensus on whether the alluvium beds should be regarded as part of the formation. These are lithologically similar to nearby sedimentary units of the Santa Fe Group.
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Several well-preserved spherical and breadcrust bombs as well as poorly preserved bipolar fusiform varieties occur with the irregular volcanic blocks. A breach on the south side of the cone permitted drainage of a lava lake in the crater. The most recently formed part of the Flourmill Centre is a well-preserved composite cone on the northwest flank. It partially overlies deposits from the southwestern vent and consists of loosely consolidated volcanic bombs pervasively interlayered with agglutinate.
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The debris avalanche was up to in volume. The Mount St. Helens National Volcanic Monument was created to preserve the volcano and allow for the eruption's aftermath to be scientifically studied. As with most other volcanoes in the Cascade Range, Mount St. Helens is a large eruptive cone consisting of lava rock interlayered with ash, pumice, and other deposits. The mountain includes layers of basalt and andesite through which several domes of dacite lava have erupted.
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The (meta)sedimentary succession starts with the 2000 to 3000 m thick Canaveilles Group in the Ediacarian about 580 million years ago. Its sediments consist mainly of shales and greywackes with intercalated rhyolites and carbonates. Within the Cadí Thrust Sheet archeocyathid–bearing limestones developed during the Lower Cambrian. At the onset of the Middle Cambrian, the Canaveilles Group is replaced by the Jujols Group, a 2000 m thick flyschoid series comprising schists, shales, and siltstones interlayered with carbonates and quartzites.
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These strata are the Catalan Bay Shale Formation (youngest), Gibraltar Limestone, Little Bay Shale Formation (oldest), and Dockyard Shale Formation (age unknown). These strata are noticeably faulted and deformed. Predominantly of shale, the Catalan Bay Shale Formation also contains thick units composed of either brown calcareous sandstone, soft shaly sandstone interbedded with bluish-black limestone, and interlayered greenish-gray marls and dark gray cherts. The Catalan Bay Shale Formation contains unidentifiable echinoid spines and belemnite fragments and infrequent Early Jurassic (Middle Lias) ammonites.
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Illite (K0.65Al2.0[Al0.65Si3.35O10](OH)2) and muscovite (KAl2(AlSi3O10)(OH)2) are both phyllosilicates similar in structure and composition. Illite is made up of thin, 1 nm, layers which are made up of tetrahedral-octahedral-tetrahedral (TOT) sheets. Illite contains more silicon, iron and magnesium than muscovite, as well as less tetrahedral aluminium and interlayered potassium. X-Ray diffraction plots provide information on angles and intensities of refracted beams which allow scientists to construct a 3D model of the crystalline structure.
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The corresponding unconformity, which exists only in the western Pyrenees, belongs to an early deformation phase of the Variscan orogeny (Breton Phase). Only in the western Pyrenees is the Lower Carboniferous (Mississippian) distinguished from the Devonian sediments by an unconformity, starting off marine with a transgressive quartz–pebble bed. Anywhere else, the Supragriotte limestones are conformably overlain by pre- orogenic sediments that begin with the Lower Cherts of the Tournaisian. The Lower Cherts comprise 50 m of black, phosphate nodule-bearing cherts interlayered with black shales.
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Both the composition and the textures of protolith strongly play a role in the formation of the resulting skarn. Reaction skarn is formed from isochemical metamorphism occurring on thinly interlayered sedimentary lithology units that involves a small scale (perhaps centimetres) metasomatic transfer of components between adjacent units.Zarayskiy, G.P., Zharikov, V.A., Stoyanovskaya, F.M., and Balashov, V.N., 1987, The Experimental Study Of Bimetasomatic Skarn Formation: International Geology Review, v. 29, p. 761-858 Skarnoid is a calc-silicate rock that is fine-grained and iron poor.
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After an interlude of grey, nodular, goniatite-bearing limestones, the Upper Cherts were deposited during the Viséan—grey or green cherts sometimes interlayered with pyroclastics and ending with grey nodular limestones. The Mississippian later on changes into the nearly 1000 m thick detrital, syn-orogenic sediments of the Kulm–facies. An exception are the western Pyrenees, where, during the Serpukhovian, dark grey, laminated limestones precede the Kulm. The diachronous Kulm sediments are a flysch-like (turbidites) interlayering of sandstones and dark shales—harbingers of the Variscan tectonic movements.
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The Gneiss is homogeneous overall, but is recognized as having four subdivisions. These are the layered gneiss member, the augen gneiss member, the streaked-augen gneiss member, and the hornblende gneiss member. Additionally, the Baltimore Gneiss outcrops into three discrete masses of uniform, well-foliated to massive granitic gneiss referred to as the Slaughterhouse Gneiss. The layered gneiss member consists of dark and light layers of gneiss bearing biotite, microcline, quartz, and plagioclase, varying from biotite schist to quartzo-feldspathic granofels interlayered on a centimeter to decimeter scale.
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The basal Graafwater Formation (300-450m thick) consists of interlayered pale brown sandstone, laminated pink siltstone and dark maroon coloured shale. Closer examination shows deposition cycles from current-bedded channel sandstones to increasing proportions of fine-grained maroon shales at the top, deposited in flood plains and lagoons. The Peninsula Formation (800-1500m thick) consisting of hard, light grey medium to coarse grained pebbly quartz sandstone, dominates the steep mountain cliffs. Current bedding and pebble layers suggest that it was originally deposited as migrating sand bars in broad river channels.
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Gmelinite from Ireland Gmelinite-Na occurs extremely rarely at the Francon Quarry, Montreal, Canada, in sills of the igneous volcanic rock phonolite which are rich in dawsonite, .Tarassoff, Peter, and Horvath, Lazlo and Elsa (2006) Mineralogical Record 37-1:35 It occurs both as pure gmelinite-Na and interlayered with chabazite in water-quenched basalts in Western Tasmania.Sutherland, F L and Bottrill, R S (2004) Zeolites of Western Tasmania, Australian Journal of Mineralogy 10-2: 59 - 72 Associated minerals include other zeolites, especially chabazite, quartz, aragonite and calcite.
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Thin interbedded sedimentary units that have silicified into impure chert mark breaks that have resulted from eruptive activity. This group ranges in age from >3547 to ~3260 Ma and is over 10 km thick. The Fig Tree Group was deposited between ~3260 and 3225 Ma. It is defined as a transitional unit of interlayered volcanic clasts and land derived sediments that were eroded from the underlying greenstone succession. The Moodies Group, post-3225 Ma, is a combination of sandstone and conglomerate originating from the erosion of the underlying greenstone unit and the uplifted plutonic rocks.
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The North Range of the Cuyuna Range was regionally metamorphosed during the Penokean orogeny, which peaked between 1,870 and 1,850 million years ago. The iron ore of the Cuyuna is a Lake Superior-type iron-formation similar to other iron formations in the region. The Mahnomen Formation has a lower member, which lacks iron oxide components, and an upper member dominated by beds of iron oxide argillite and lean iron- formation interlayered with non-iron oxide argillite, siltstone and quartzose sandstone. The Trommald Formation - the principal iron formation of the North Range - is a chemically precipitated unit.
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Each formation is separated from the other by low-angle faults, called detachments, along which they have been thrust southward over each other. From the summit of Mount Everest to its base these rock units are the Qomolangma Formation, the North Col Formation, and the Rongbuk Formation. The Qomolangma Formation, also known as the Jolmo Lungama Formation, runs from the summit to the top of the Yellow Band, about above sea level. It consists of greyish to dark grey or white, parallel laminated and bedded, Ordovician limestone interlayered with subordinate beds of recrystallised dolomite with argillaceous laminae and siltstone.
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The lower volcanic section is covered by garnet and diopside bearing calc–silicate layers and finely layered metasediments composed of coarse-grained actinolite, hornblende and biotite followed by pelites and semi-pelites that are intruded by separate sills. In the Ridge Lake area, the volcanic belt includes an interlayered series of amphibolite, gabbro, iron formation, sulfidic schist and metasediments. Geochemical results of pillow lavas and chill boundaries along five transects across the volcanic belt suggest the existence of three chemically different magma types within the Bravo Lake Formation. Lavas of the volcanic belt display geochemical characteristics similar to modern ocean- island–basalt groups.
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Erupted 6.71 ± 0.04 mya, the Panizos ignimbrite proper is a complex structure with several cooling units and an interlayered pyroclastic deposit, which contains pumice, sandstone boulders up to two metres thick and has carved channels into the lower unit. At the edge of the plateau the upper and lower cooling units are and thick. In the plateau centre, the lower unit is completely hidden beneath the now more than thick upper unit. The lower unit begins with one metre of lapilli and above it thick ignimbrite layers that become increasingly non-welded farther up with vapour phase components appearing.
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The ice sheet, which stopped around present-day Finchley, deposited boulder clay to form Dollis Hill and Hanger Hill. Its torrent of meltwater gushed through the Finchley Gap and south towards the new course of the Thames, and proceeded to carve out the Brent Valley in the process. Upon the valley sides there can be seen other terraces of brickearth, laid over and sometimes interlayered with the clays. These deposits were brought in by the winds during the periglacial periods, suggesting that wide, flat marshes were then part of the landscape, which the new river Brent proceeded to cut down.
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Palynological data from sedimentary layers samples at the base of four lava flow sequences constrain the onset of the CAMP, since there is no evidence of depositional hiatus or tectonic deformation at the bottom of the lava flow piles . The palynological assemblage observed in these basal layers is typical of Late Triassic age, similar to that of the uppermost Triassic sedimentary rocks of eastern North America . Samples from interlayered limestone in lava flows provided unreliable palynological data. One limestone bed from the top to the central High Atlas upper basalts yielded a Late Triassic palynological assemblage.
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The Upper Carixian consists of very fossiliferous (Aegoceras capricornu) marly limestone layers interlayered with grey marls. These are followed by ammonite-bearing (Amaltheus margaritatus) and oyster-bearing (Gryphaea cymbium) marls indicating a shelf environment open to the spreading Atlantic Ocean. During the Lower Domerian, a connection to the Paris Basin is breached for the first time via the Seuil du Poitou and also to the Jurassic sea of southeastern France via the Détroit de Rodez and the Détroit de Carcassonne. During the Upper Domerian, another regression sets in leaving sandy limestones very rich in fossils (Pleuroceras spinatum, Pecten aequivalvis).
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The remainder of the North Col Formation, exposed between on Mount Everest, consists of interlayered and deformed schist, phyllite, and minor marble. Between , the North Col Formation consists chiefly of biotite-quartz phyllite and chlorite-biotite phyllite intercalated with minor amounts of biotite-sericite-quartz schist. Between , the lower part of the North Col Formation consists of biotite-quartz schist intercalated with epidote-quartz schist, biotite-calcite-quartz schist, and thin layers of quartzose marble. These metamorphic rocks appear to be the result of the metamorphism of Middle to Early Cambrian deep sea flysch composed of interbedded, mudstone, shale, clayey sandstone, calcareous sandstone, graywacke, and sandy limestone.
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The Khewra Salt Mine is excavated within the base of a thick layer of highly folded, faulted, and stretched Ediacaran to early Cambrian evaporites of the Salt Range Formation. This geological formation consists of a basal layer of crystalline halite, which is intercalated with potash salts. This basal layer is overlain by gypsiferous marl, which is covered by interlayered beds of gypsum and dolomite with infrequent seams of oil shale. These strata are overlain by of Neoproterozoic to Eocene sedimentary rocks that have been uplifted and eroded along with the Salt Range Formation to create the Salt Range at the southern edge of the Pothohar Plateau.
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Taconite (IPA: ['tækənaɪt]) is a variety of iron formation, an iron-bearing (over 15% iron) sedimentary rock, in which the iron minerals are interlayered with quartz, chert, or carbonate. The name "taconyte" was coined by Horace Vaughn Winchell (1865–1923) – son of Newton Horace Winchell, the Minnesota State Geologist – during their pioneering investigations of the Precambrian Biwabik Iron Formation of northeastern Minnesota. He believed the sedimentary rock sequence hosting the iron-formation was correlative with the Taconic orogeny of New England, and referred to the unfamiliar and as-yet-unnamed iron-bearing rock as the 'taconic rock' or taconyte.Winchell, Horace V. (1891) "The Mesabi iron range," in: Winchell, Newton H., ed.
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The first phase of activity resulted in the creation of Armadillo Peak seven million years ago, today represented by an eroded remnant of a small caldera flanked by steep-sided light-coloured secondary lava domes, including Cartoona Peak, Tadeda Peak, IGC Centre, and Sezill Volcano, and a thick pile of interlayered light-coloured lava flows, pyroclastic flows, air-fall pumice, and epiclastic deposits. It is the most central of the four central volcanoes and its summit is capped by of fine-grained silica-rich trachyte lava flows which were ponded inside the caldera to produce a lava lake six million years ago during its final stage of activity.
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The porphyritic granite was named the Mint Wash Granodiorite by DeWitt and others for exposures along Mint Wash east of Granite Mountain. In composition, it is an alkali-calcic granodiorite to granite. Zircons from this granite yielded a U-Pb date of 1680 +/- 16 Ma. The Mint Wash Granodiorite comprises the Mint Wash Pluton that has intruded into Paleoproterozoic sedimentary, metasedimentary, and metavolcanic rocks. On the northern end of Granite Mountain, these strata include weakly to moderately metamorphosed mudstone, siltstone, and fine-grained sandstone; basalt lava flows; ferruginous, white and dark laminated silica rock; infrequently laminated, epidote-silica rock; thinly interlayered silica and carbonate; laminated, highly platy, talc and/or pyrophyllite schist.
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Though named after New Jersey, the fossil-bearing strata of the Raritan and overlying Magothy formations are also exposed in several neighboring U.S. states, including Maryland through south and central New Jersey, across Staten Island and Long Island (coastal areas of New York state), to a northern exposure at Martha's Vineyard, an island of Massachusetts. Of the two formations that New Jersey amber is found in, the Raritan Formation underlies the Magothy Formation. The Magothy formation is reported by Wilson's 1967 paper describing Sphecomyrma freyi as having exposures in Maryland, New Jersey, New York, Delaware, and other unspecified islands along the New England coastline. The formation consists of gray to dark brown clay beds interlayered in light-colored sands.
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Evidence for contemporaneous volcanism and glaciation is widespread throughout the mountain. This includes interlayered unconsolidated fluvioglacial and tuffaceous deposits, tills and glacial erratics at the base of tuffs and lava flows, lahars composed of till and agglomerate, tuyas on the uppermost surface of the shield and as outliers, till cemented by siliceous sinter and the presence of freshwater pillow basalts and volcano-glacial tuff breccias. It is possible that geothermal outputs at Level Mountain had an influence on dynamics of past ice sheets much like the modern Grímsvötn caldera is an important heat source beneath Vatnajökull in Iceland. However, like other large NCVP volcanoes, much of Level Mountain was formed prior to glaciation.
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Himalayan salt Himalayan salt is mined from the Salt Range mountains, the southern edge of a fold-and-thrust belt that underlies the Pothohar Plateau south of the Himalayas. Himalayan salt comes from a thick layer of Ediacaran to early Cambrian evaporites of the Salt Range Formation. This geological formation consists of crystalline halite intercalated with potash salts, overlayed by gypsiferous marl and interlayered with beds of gypsum and dolomite with infrequent seams of oil shale that accumulated between 600 and 540 million years ago. These strata and the overlying Cambrian to Eocene sedimentary rocks were thrust southward over younger sedimentary rocks, and eroded to create the Salt Range.Jaumé, S.C. and Lillie, R.J., 1988.
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Critics of a purely tectonic hypothesis have also noted that although pit crater chains (central to the diking hypothesis) are generally aligned and coincident with graben, they are occasionally found to bifurcate and to cross coeval graben in a perpendicular direction in the vicinity of Noctis Labyrinthus. Some authors have also proposed that Noctis Labyrinthus' chasmata may have formed due to extensional faulting in weakened rocks composed of interlayered tuff and lava flows, known to produce pit crater chains parallel to graben. Other authors have suggested that phreatomagmatic processes were associated with the formation of the Noctis Labyrinthus chasmata. This hypothesis is not widely favored because chaos terrain morphology, proposed to form from this mechanism, is not found in the Noctis Labyrinthus fracture network.
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The Thlewyco sequence represents the main construction phase of the volcano and forms an outward dipping, annular succession around the Innerring sequence, with an aggregate thickness of -. Its stratigraphy changes dramatically around the crater, varying from five cycles of andesitic and rhylotic lava, followed by succession of volcanistic debris on the north side, to 30 subaerial andesitic flows and rare pyroclastic and epivolcaniclastic units on the eastern side, to interlayered dacitic and andesitic lava and tuff overlain by a thick succession of voluminous, nonwelded, ash-flow tuff and volcaniclastic rocks on the south side. Volcanism in this sequence ended with the eruption of large rhyolite and dacite dome-flow complexes (U-Pb zircon dated at 2.692 Ga). The Innerring and Thlewycho sequences represent a complex history of explosive eruptions from numerous eruptive centers.
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An unusual feature of Allonautilus scrobiculatus is its periostracum or "shell skin". The "shaggy" periostracumon is present on freshly caught samples, and is thickly interlayered, resembling slimy hair. Allonautilus scrobiculatus, or otherwise known as the crusty nautilus or fuzzy nautilus is a species of cephalopod. The species dates back roughly 500 million years and for decades, has impressed biologists and researchers with the species’ evolutionary grit, surviving for several millions of years, unchanged. A. scrobiculatus is considered by many to be a “living fossil”, similar to coelacanths and horseshoe crabs. A. scrobiculatus’ most recently sighting was in July 2015 by biologist Peter Ward of the University of Washington. Ward’s colleague, Bruce Saunders, a geologist from Bryn Mawr College was the one who had initially sighted the organism all the way back in 1984.
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Geological make-up of Leon County Leon County encompasses basement rock composed of basalts of the Triassic and Jurassic from ~251 to 145 million years ago interlayered with Mesozoic sedimentary rocks. The layers above the basement are carbonate rock created from dying foraminifera, bryozoa, mollusks, and corals from as early as the Paleocene, a period of ~66—55.8 Ma.Geology of Florida, University of Florida During the Eocene (~55.8—33.9 Ma) and Oligocene (~33.9—23 Ma), the Appalachian Mountains began to uplift and the erosion rate increased enough to fill the Gulf Trough with quartz sands, silts, and clays via rivers and streams. The first sedimentation layer in Leon County is the Oligocene Suwannee Limestone in the southeastern part of the county as stated by the United States Geological Survey and Florida Geological Survey. The Early Miocene (~23.03—15.7 Ma) sedimentation in Leon County is Hawthorn Group, Torreya Formation and St. Marks Formation and found in the northern two-thirds of the county.
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