How to use Triassic in a sentence
Diabases pierce to Devonian rocks, and olivine rocks appear as dykes amidst the Triassic deposits.
The Mesozoic begins with a Triassic land period in the mainland of Australia; while the islands of the Australasian festoon contain the Triassic marine limestones, which fringe the whole of the Pacific. The Triassic beds are best known in New South Wales, where round Sydney they include a series of sandstones and shales.
Triassic slates appear in the south-east.
And when we know that the Chrysomelidae and Buprestidae also lived in Triassic, and the Carabidae, Elateridae, Cerambycidae and Scarabaeidae, in Liassic times, we cannot doubt that the great majority of our existing families had already been differentiated at the beginning of the Mesozoic epoch.
Russia, rich in salt-springs, but very poor in fossils, are now held by most Russian geologists to be Triassic. The Permian deposits contain marine shells and also remains of plants similar to those of England and Germany.Advertisement
In the centre of the folds fossiliferous beds with crinoids have been found, and the black slates at the top of the series contain Myophoria and other fossils, indicating that the rocks are of Triassic age.
The Triassic deposits of the Verkhoyansk Range show that this land did not extend to the Bering Sea; while the marine Mesozoic deposits of Japan on the east, the western Tian-shan on the west and Tibet on the south give us some idea of its limits in other directions.
In the sandstone Myophoria and other Triassic fossils have been found, and it appears to belong to the Rhaetic or Upper Trias.
In the Triassic rocks of Switzerland remains of weevils (Curculionidae) occur, a family which is considered by many students the most specialized of the order.
Five well-contrasted types of scenery in Derbyshire are clearly traceable to as many varieties of rock; the bleak dry uplands of the north and east, with deep-cut ravines and swift clear streams, are due to the great mass of Mountain Limestone; round the limestone boundary are the valleys with soft outlines in the Pendleside Shales; these are succeeded by the rugged moorlands, covered with heather and peat, which are due to the Millstone Grit series; eastward lies the Derbyshire Coalfield with its gently moulded grasscovered hills; southward is the more level tract of red Triassic rocks.Advertisement
Much of the Triassic area is covered superficially by glacial drift and alluvium of the Trent.
The occurrence of weevils - among the most specialized of the Coleoptera - in Triassic rocks shows us that this great order of metabolous insects had become differentiated into its leading families at the dawn of the Mesozoic era, and that we must go far back into the Palaeozoic for the origin of the Endopterygota.
In the neighbourhood of Nottingham, and other places in the Midlands, barytes forms a cementing material in the Triassic sandstones; amber-coloured crystals of the same mineral are found in the fuller's earth at Nutfield in Surrey; and the septarian nodules in London Clay contain crystals of barytes as well as of calcite.
Along the west frontier there appear broad and strongly marked zones of Cretaceous limestone, alternating with Jurassic and Triassic, joined by a strip of Palaeozoic formations running from the north-west corner of Bosnia.
In the south-east of Bosnia the predominant formations are Triassic and Palaeozoic strata with red sandstone and quartzite.Advertisement
During the Triassic and Jurassic periods even the basin of the Amazon appears to have been dry land.
These are composed chiefly of Triassic beds, but Jurassic and Cretaceous beds take some share in their formation.
Rising amid the ancient gneiss rocks of the St Gotthard, the Rhine finds its way down to the Lake of Constance between layers of Triassic and Jurassic formation; and between that lake and Basel it penetrates the chalk barrier of the Jura.
Peletan classes all these limestones as Triassic. Triassic beds of the Pacific coastal type occur in a band along the south-western coast.
Mesozoic rocks are represented by slates containing Ammoniles and Monotis, evidently of Triassic age, rocks containing Ammonites Bucklandi of Liassic age, a series of beds rich in plants of Jurassic age, and beds of Cretaceous age containing Trigonia and many other fossils.Advertisement
But Professor Park has obtained Jurassic fossils in the Maitai series; so that it will probably be ultimately divided between the Carboniferous and Jurassic. The two systems should, however, be separable by an unconformity, unless the Maitai series also includes representatives of the Kaihiku series (the New Zealand Permian), and of the Wairoa series, which is Triassic.
New Zealand includes representatives of all the three Mesozoic systems. The Hokanui group comprises the Triassic Wairoa .and Otapira beds, and the Jurassic Mataura beds.
Below it, Triassic beds are exposed from Lisburn to Island Magee, giving sections of red sands and marls.
The glens of Antrim are deep notches cut by seaward-running streams through the basalt scarp, their floors being formed of Triassic or older rocks.
The gypsiferous and saliferous marls of Shellata, Suk Ahras and Ain Nussi have yielded Triassic fossils.Advertisement
Triassic rocks are considered to be present in Constantine and in the Jurjura.
Smith Woodward has observed that the decline of many groups of fishes is heralded by the tendency to assume elongate and finally eel-shaped forms, as seen independently, for example, among the declining Acanthodians or palaeozoic sharks, among the modern crossopterygian Polypterus and Calamoichthys of the Nile, in the modern dipneustan Lepidosiren and Protopterus, in the Triassic chondrostean Belonorhynchus, as well as in the bow-fin (A7nia) and the garpike (Lepidosteus).
The Triassic and Jurassic systems are met with only in scattered patches.
A wonderful series of these forms occurs in southern Utah, where in passing northward from the Carboniferous platform one ascends in succession the Vermilion Cliffs (Triassic sandstones), the ViThite Cliffs (Jurassic sandstones, of remarkably cross-bedded structure, interpreted the dunes of an ancient desert), and finally the Pink Cliffs (Eocene strata of fluviatile and lacustrine origin) of the high, forested plateaus.
Another consequence of revived erosion is seen in the occurrence of great landslides, where the removal of weak (Permian) clays has sapped the face of the Vermilion Cliffs (Triassic sandstone), so that huge slices of the cliff face have slid down and forward a mile or two, all shattered into a confused tumult of forms for a score or more of miles along the cliff base.
They are distinguished with difficulty from the succeeding Triassic, for the beds have very few fossils.
Triassic SystemThis system has but limited representation in the eastern part of the United States, being known only east of the Appalachian Mountains in an area which was land throughout most of the Palaeozoic era, hut which was deformed when the eastern mountains were developed at the close of the Palaeozoic. In the troughs formed in its surface during this time of deformation, sediments of great thickness accumulated during the Triassic period.
In the western plains and in the western mountains the Triassic is not clearly separated from the Permian in most places.
The Triassic system is well developed on the Pacific coast, where its strata are of marine origin, and they extend inland to the Great Basin region.
As in other parts of the earth, the Triassic was the age of gymnosperms, which were represented by diverse types.
On the Pacific coast marine Jurassic beds reach in from the Pacific to about the same distance as the Triassic system.
The close of the period, too, saw the exclusion of the sea from the Pacific coast east of the Sierras, and the disappearance, so far as the United States is concerned, of the great north-western bay of the late Jurassic. Before the close of the period, the aridity which had obtained during the Permian, and at least a part of the Triassic, seems to have disappeared.
The lode was an ore channel of great dimensions included within volcanic rocks of Tertiary age, themselves broken through pre-existing strata of Triassic age, and exhibited some of the features of a fissure vein, combined in part with those of a contact deposit and in part with those of a segregated vein.
Prince Edward Island, the smallest province of Canada, is low and undulating, based on Permo-Carboniferous and Triassic rocks affording a red and very fertile soil, much of which is under cultivation.
In Dauphin county is a quarry of bluish-brown Triassic sandstone that has been used extensively especially in Philadelphia, for the erection of the so-called brown stone fronts.
Triassic beds with Halobia and Monotis are well-developed in Rotti and appear also to occur in Timor.
The chief geological formations belong to the Cretaceous system, backed towards the north and east by Jurassic and Triassic formations.
Triassic Permian Plutonic Rocks Volcanic Rocks West of a line which runs from Lake Constance to Lago Maggiore the zones already described do not continue with the same simplicity.
They consist chiefly of Jurassic and Triassic beds, but it is the Trias and the Jura of the Eastern Alps and not of Switzerland.
But it is divided longitudinally by a well-marked belt of stratified deposits, known as the zone of the Briangonnais, composed chiefly of Carboniferous, Triassic and Jurassic beds.
The origin of the schistose rocks has long been under discussion, and controversy has centred more particularly around the schistes lustres, which are held by some to be of Triassic age and by others to be pre-Carboniferous and even, perhaps, Archaean.
In the Eastern Alps the central ridge seems to have been in existence at least ag as early as Triassic times, but it has since been subject p to several oscillations.
No Permian beds are known, and for many years Mesozoic deposits were supposed to be entirely absent, but Triassic clays and sandstones with Daonella have been found in the upper part of the basin of the Kwalu (East Sumatra).
Except along the southern border of the Ardennes, and at one or two points in the middle of the Palaeozoic massif, Triassic and Jurassic beds are unknown in Belgium, and the Palaeozoic rocks are directly and unconformably overlaid by Cretaceous and Tertiary deposits.
The western boundary of this valley is formed in the first instance by the Vosges, where granite summits rise from under the surrounding red Triassic rocks (Suizer Belchen, 4669 ft.).
Between the old rocks of the Rhine on the west and the ancient inassif of Bohemia on the east a vast area of Triassic beds extends from Hanover to Basel and from Metz to Bayreuth.
Over the greater part of this region the Triassic beds are free from folding and are nearly horizontal, but faulting is by no means absent, especially along the margins of the Bohemian and Rhenish hills.
The Triassic beds must indeed have covered a large part of these old rock masses, but they have been preserved only where they were faulted down to a lower level.
Along the southern margin of the Triassic area there is a long band of Jurassic beds dipping towards the Danube; and at its eastern extremity this band is continuous with a synclinal of Jurassic beds, running parallel to the western border of the Bohemian massif, but separated from it by a narrow strip of Triassic beds.
Towards the north, in Hanover and Westphalia, the Triassic beds are followed by Jurassic and Cretaceous deposits, the latter being here the more important.
Triassic rocks form a discontinuous band along the northern coast, and are especially well developed in the neighbourhood of Palermo.
In many parts of the world, including the British area, the Triassic age offered conditions especially favourable for the formation of large salt-deposits.
Antrim, Ireland, is undoubtedly of Triassic age.
There is a central region, roughly triangular in shape, with its base resting upon the Quaternary K Triassic Tertiary Carboniferous q & Metamorphic 7 Jurassic Aegean Sea and its apex in Servia.
The Triassic system is only feebly represented.
Geologically the group is composed mainly of Triassic, Cretaceous and Tertiary strata, penetrated by intrusive rocks.
The sandstones with gypsum, copper and sulphur of Dombe are doubtfully considered to be of Triassic age.
The Triassic rocks are arranged in two groups, a lower, composed of conglomerates and sandstones, and an upper one consisting of red and mottled shales and marls with thin sandstones and nodular limestones.
Pseudomonotis salinaria, a Triassic form, has been noted from the schists of the west of Borneo.
Triassic, Jurassic and Cretaceous beds form a band south of the Sea of Marmora, probably the continuation of the Mesozoic band of the Black Sea coast.
Occasional hard rock ridges rise to a moderate elevation above the general level, while areas of unusually weak Triassic sandstones have been worn down to form lowlands.
The Triassic formation (Rhaetic division) occurs in the northern part of Malmohus.
Triassic beds lie along the south side of the upper Zhob, and Fusulina limestone has also been found there.
The Triassic fossils are still more closely allied, more than a third of the species being identical.
Supposed Triassic beds are found, but they are confined chiefly to the eastern margin of the Mesozoic area north of Lisbon.
There are within the state four distinct topographic belts - the Appalachian, the Highlands, the Triassic Lowland and the Coastal Plain.
The third belt, called the Triassic Lowland, occupies about one-fifth of the surface of the state.
The' four topographic belts of the state correspond very closely to the outcrops of its geological formations; the rocks of the Appalachian belt being of Palaeozoic age; the formation of the Highlands, Archaean; that of the Triassic Lowland, Triassic; that of the irregular hills of the Coastal Plain, Cretaceous and Tertiary.
Of the streams of the Highlands and the Triassic Lowland, the Passaic river is the most important.
The Triassic age of the Hawkesbury Sandstone is supported by the evidence of the fossil fish; though, according to Dr Smith Woodward, they may perhaps be Rhaetic, .'But the fossil plants of which the chief are Taeniopteris daintreei and Thinnfeldia odontopteroides are regarded by Seward as Lower Jurassic. At Talbragar there is a bed containing Jurassic fish, which rests in an erosion hollow in the Hawkesbury Sandstone.
The Talbragar beds, then, may be representative of the Jurassic; and the underlying Hawkesbury Sandstone may be Upper Triassic. The Cretaceous system is widely developed in the western part of the state, where it is represented by two divisions.
This is shown by palaeontological evidence; and some of the most successful bores, such as those at Coonamble, Moree, Gil Gil and Euroka, have pierced rocks of Triassic age, corresponding with the Ipswich Coal Measures.
The hills and uplands of ancient rocks do not form regular ranges, but rise like islands in four distinct groups from a plain of New Red Sandstone (Permian and Triassic), which separates them from each other and from the newer rocks of the Eastern Division.
It is built up of nearly uniform sheets of Mesozoic rock, the various beds of the Jurassic lying above the New Red Sandstone (Triassic), and dipping south-eastward under the successive beds of the Cretaceous system.
On both sides of the arch, east and west, the Coal Measures remain intact, forming outcrops which disappear towards the sea under the more recent strata of Permian or Triassic age.
To the west and south the Coal Measures dip gently under the New Red Sandstone, to reappear at several points through the Triassic plain.
Across the moors, on the western side of the anticline, the vast and dense population of the Lancashire coal-field is crowded in the manufacturing towns surrounding the great commercial centre, Manchester, which itself stands on the edge of the Triassic plain.
Between the separate uplands there extends a plain of Permian and Triassic rocks, which may conveniently be considered as an The mid intermediate zone between the two main divisions.
Smaller patches of the Coal Measures appear near Tamworth and Burton, while deep shafts have been sunk in many places through the overlying Triassic strata to the coal below, thus extending the mining and manufacturing area beyond the actual outcrop of the Coal Measures.
The low escarpments of the harder beds of the Lias are the real, though often scarcely perceptible, boundary between the Triassic plain and the Jurassic belt.
Reading flourishes from its position on the edge of the London Tertiary Basin, Croydon is a suburb of London, and Hull, though on the Chalk, derives its importance from the Humber estuary, which cuts through the Chalk and the Jurassic belts, to drain the Triassic plain and the Pennine region.
The Eastern plain thus includes a portion of the Triassic plain in the north, a portion of the Jurassic and Chalk belts in the middle, and a portion of the Tertiary plain of the London Basin in the south.
But, on the other hand, the broad clay plains of all formations, the Cretaceous sandstones, and the Triassic plain, are peopled more densely than any other district without mineral wealth or sea trade.
Its central core of Lower Carboniferous rock is broadly displayed towards the north, while southward it contracts; on either side lie the younger rocks, the coal-fields, the Permian strata and the Triassic formations, the last-named, while sweeping round the southern extremity of the Carboniferous axis of the uplift from its eastern and western flanks, spread out in a large sheet over the midland counties.
The Triassic rocks, red sandstones, marls and conglomerates cover a broad area in the Midlands in Worcestershire, Warwickshire and Leicestershire, whence they may be followed south-westward through Somerset to the coast at Sidmouth, and northward, round either flank of the Pennine Hills, through Nottinghamshire and Yorkshire to Middlesbrough on the one hand, and upon the other through Staffordshire, Cheshire and Lancashire to Carlisle.
Desert conditions, with confined inland seas, marked the Permian and Triassic periods.
During the Triassic and Jurassic periods the genus Baiera - no doubt a representative of the Ginkgoales--was widely spread throughout Europe and in other regions; Ginkgo itself occurs abundantly in Mesozoic and Tertiary rocks, and was a common plant in the Arctic regions as elsewhere during the Jurassic and Lower Cretaceous periods.
A wellknown fossil conifer from Triassic strata - Voltzia heterophylly - also illustrates a marked dissimilarity in the leaves of the same shoot.
Neumayr adduced the Triassic sea-urchin Tiarechinus, in which the apical system forms half of the test, as an argument for the origin of Echinoidea from an ancestor in which the apical system was of great importance; but a genus appearing so late in time, in an isolated sea, under conditions that dwarfed the other echinoid dwellers therein, cannot seriously be thought to elucidate the origin of pre-Silurian Echinoidea, and the recent discovery of an intermediate form suggests that we have here nothing but degenerate descendants of a well-known Palaeozoic family (Lepidocentridae).
The order is Triassic to Recent.
In the central portion, which belongs to the Triassic formation, magnesian limestone, ferruginous sandstone and gypsum are representative rocks.
Possibly mammalian remains also occur in the antecedent Triassic epoch, some palaeontologists regarding the South African Tritylodon as a mammal, while others consider that it was probably a reptile.
It may be explained that the Theromorpha, or Anomodontia, are those extinct reptiles so common in the early Secondary (Triassic) deposits of South Africa, some of which present a remarkable resemblance in their dentition and skeleton to mammals, while others come equally near amphibians.
Be this as it may, the Apennines, excepting in Calabria, are formed chiefly of Triassic, Jurassic, Cretaceous, Eocene and Miocene beds.
Throughout the Triassic and Jurassic periods nearly all Turkestan remained a continent indented by gulfs and lagoons of the south European Triassic and Jurassic sea.
The Upper Coal-Measures, as a rule, have been lost by denudation, much of which occurred before Triassic times.
The last named is in part concealed by Triassic strata.
The Triassic beds rest on the various Carboniferous series in turn, indicating, as in England, the amount of denudation that followed on the uplift of the Hercynian' land.
The Triassic sandstones and marls, with marine Rhaetic beds above, are preserved mainly round the basaltic plateaus of the north-east, and extend for some distance into county Down.
West of Cracow the Cretaceous beds are underlaid by Jurassic and Triassic deposits, the general dip being eastward.
Suess, which in Permian and Triassic times stretched across the European area from west to east.
These hills are largely formed of volcanic rocks of late Tertiary age; but near the Platten See Triassic beds of Alpine type are well developed.
The famous cinnabar and mercury mines of Idria in Carniola are in Triassic beds; and the gold and silver of northern Hungary and of Transylvania are associated with the Tertiary volcanic rocks.
The lowest is the Triassic Keuper found in the Isle of Axholme and the valley of the Trent in the form of marls, sandstone and gypsum.
The Triassic system is well developed in the north of the peninsula along the Cantabrian chain and eastwards to the Mediterranean.
Upon it, in the trough thus formed, rest conformably the basal strata of the Cretaceous; the Jurassic and Triassic being wholly absent (unless in the extreme north-west).
It is usually regarded as beginning with a fresh-water series containing the remains of fish and labyrinthodonts; but as it also contains Vertebraria it is probably Palaeozoic; and this series is covered by sandstones and shales which are probably of Triassic age.
The Mesozoic era, as defined in geological textbooks, includes the Triassic, Jurassic and Cretaceous epochs; but from the point of view of the evolution of plants and the succession of floras, this division is not the most natural or most convenient.
Our knowledge of the Triassic vegetation is far from extensive; this is no doubt due in part to the fact that the conditions under which the Triassic rocks were deposited were not favourable to the existence of a luxuriant vegetation.
Moreover, the Triassic rocks of southern Europe and other regions are typical marine sediments.
Among plants from Lower Triassic strata there are a few which form connecting links with the older Permo-Carboniferous flora; of these we have a species, described by Blanckenhon as Sigillaria oculina, which may be correctly referred to that genus, although an inspection of a plaster-cast of the type-specimen in the Berlin Bergakademie left some doubt as to the sufficiency of the evidence for adopting the generic name Sigillaria.
Another Triassic genus, Pleuromeia, is of interest as exhibiting, on the one hand, a striking resemblance to the recent genus Isoetes, from which it differs in its much larger stem, and on the other as agreeing fairly closely with the Palaeozoic genera Lepidodendron and Sigillaria.
There is, however, a marked difference, as regards the floras as a whole, between the uppermost Palaeozoic flora of the northern hemisphere and such species as have been recorded from Lower Triassic beds.
Passing over the few known species of plants from the middle Trias (Muschelkalk) to the more abundant and more widely spread Upper Triassic species as recorded from Germany, Austria, Switzerland, North America and elsewhere, we find a vegetation characterized chiefly by an abundance of Ferns and Cycads, exhibiting the same general facies as that of the succeeding Rhaetic and Lower Jurassic floras.
Representatives of the Ginkgoales constitute characteristic members of the later Triassic floras, and these, with other types, carry us on without any break in continuity to the Rhaetic floras of Scania, Germany, Asia, Chile, Tonkin and Honduras (Map A, VIII.), and to the Jurassic and Wealden floras of many regions in both the north and south hemispheres.
There is some evidence for the occurrence of similar Chara " fruits" in middle Triassic rocks; some doubtful fossils from the much older Devonian rocks have also been quoted as possible examples of the Charophyta.
The Palaeozoic Calamites were succeeded in the Triassic period by large Equisetites, differing, so far as we know, in no essential Equ;se- respect from existing Equisetums. The large stems taceae.
Of other Equisetales there are Schizoneura and Phyllotheca; the former first appears in Lower Gondwana rocks as a member of the Glossopteris flora, migrating at a later epoch into Europe, where it is represented by a Triassic species.
Of the Ophioglossaceae there are no satisfactory examples; one of the few fossils compared with a recent species, Ophioglossum palmatum, was described several years ago from Triassic rocks under the name Cheiropteris, but the resemblance is one of external form only, and practically valueless as a taxonomic criterion.
The Gleicheniaceae appear to have been represented by Triassic species in North America and Europe, and more abundantly in Jurassic, Weal den, or Lower Cretaceous rocks 3 4 in Belgium, Greenland, Poland s and elsewhere.
Sphenozamites, chiefly from French localities, which are referred to 1 fronds, which therg is good reason to refer to the Cycadales in the Cycads because of their similarity to the pinnate fronds of Upper Triassic, Rhaetic, Jurassic and Wealden rocks in India, modern Cycadaceae.
Passing higher up the geological series, we find but scanty records of the vegetation that existed during the closing ages of the Permian period, and of the plants which witnessed the beginning of the Triassic period we have to be content with the most fragmentary relics.
It is in rocks of Upper Triassic and Rhaetic age that abundant remains of rich floras are met with, and an examination of the general features of the vegetation reveals a striking contrast between the Lower Mesozoic plants and those of the Palaeozoic period.
Below the cretaceous Tertiary escarpment, the low ground is underlain by soft sedimentary rocks of the Triassic Mercia Mudstone Group.
The Triassic period begins in the wake of the greatest mass extinction of all time.
Upto 6 basaltic dikes intrude into these Triassic marls and mudstones.
The Waterloo mudstone Formation spans the Triassic Jurassic boundary, and comprises dark gray mudstones and shales, alternating with gray limestones.
The geology of much of the western half of Leicestershire is dominated by the red mudstones of the Triassic aged Mercia Mudstone Group.
On the north side of the Lagan Valley the Triassic sandstone is succeeded by reddish Triassic mudstone which does not provide a water supply.
At the north end of the reserve area there is an outcrop of Triassic sandstone.
The soils on the Triassic rocks are usually sandy and often pebbly.
Toward the end of the Triassic, sea-level started to rise and a warm, shallow sea developed over what is now southern England.
The succession is interpreted as representing the latest Triassic transgression of the sea; this continued into the earliest Jurassic.
The Permian and Triassic deposits were also, for the most part, of continental origin; but with the formation of the Rhaetic beds the sea again began to spread, and throughout the greater part of the J ueassic period it covered nearly the whole of the country except the Central Plateau, Brittany and the Ardennes.
Southeast of the Triassic Lowland lies the fourth topographic belt, the Coastal Plain, containing an area of 4400 sq.
The first Th is the Jurassic Belt, sweeping along the border of the eas Triassic plain from the south coast at the mouth of the div sion.
Geography, environment and climate During the Triassic, the ' British Isles ' formed part of the supercontinent known as Pangea.