Timing Of Orogeny Research Articles

Early Palaeozoic unconformity across the Timanides, NW Russia

Abstract The Lower Palaeozoic sequences, unconformably overlying the Timanides of Timan, Pechora, Pai-Khoi, Vaigach, Novaya Zemlya and the Polar, Northern, Middle and Southern Urals are described and interpreted with regard to their stratigraphy, sedimentation, structure and biogeography. These mainly shallow marine sedimentary successions, with associated igneous rocks (largely alkaline), are Ordovician in age, reaching back into the Late Cambrian in some areas, particularly in the east, along the front of the Urals. They were deposited during rifting of Baltica’s northeastern margin and subsequent development of a passive continental margin. The underlying, mainly Neoproterozoic basement of turbidites in the west and calc-alkaline volcanites and ophiolites further east are briefly referred to, with particular emphasis on the age of the youngest rocks. Based on these data, a Timanian orogenic belt can be traced along the northeastern and eastern margin of the East European Craton. The timing of orogeny can be constrained to the Vendian, perhaps extending into the Early Cambrian.

Structural geology of the Lardeau Group near Trout Lake, British Columbia: implications for the structural evolution of the Kootenay Arc

The Lardeau Group is a heterogeneous assemblage of lower Paleozoic eugeoclinal strata present in the Kootenay Arc in southeastern British Columbia. It is in fault contact with lower Paleozoic miogeoclinal strata for all or some of its length along a structure termed the Lardeau shear zone. The Lardeau Group was deformed prior to mid-Mississippian time, as manifested by layer-parallel faults, folds, and evidence for early greenschist-facies metamorphism. Regional constraints indicate probable Devono-Mississippian timing of orogeny, and possible juxtaposition of the Lardeau Group over miogeoclinal strata along the Lardeau shear zone at this time. Further ductile deformation during the Middle Jurassic Columbian orogeny produced large folds with subhorizontal axes, northwest-striking foliation and faults, and orogen-parallel stretching lineations. This deformation was apparently not everywhere synchronous, and may have continued through Late Jurassic time northeast of Trout Lake. This was followed by Cretaceous(?) dextral strike-slip and normal movement on the Lardeau shear zone and other parallel faults. While apparently the locus of several episodes of faulting, the Lardeau shear zone does not record the accretion of far-travelled tectonic fragments, as sedimentological evidence ties the Lardeau Group and other outboard units to the craton.

Late Palaeozoic sedimentation along the Appalachian orogen

Summary The sedimentological framework of post-Early Devonian strata in the Appalachians includes two different domains. S of the New York recess in the foreland fold-thrust belt, clastic wedges of two different ages (Devonian-Early Mississippian and Late Mississippian-Pennsylvanian) constitute the sedimentological record of the Acadian and Alleghanian orogenies. The widespread semicircular clastic wedges prograded cratonward across broad foreland basins from orogenic provenances. Distribution of siliciclastic sediments suggests a genetic relation to large-scale curves (salients and recesses) of the orogenic belt and indicates variation in time of orogeny along strike. N of the New York recess in the more interior part of the orogen, Devonian to Permian siliciclastic sediments derived from local fault-block uplifts filled and overflowed pull-apart basins associated with mainly dextral wrench faults. The history of sediment supply and deposition varies from basin to basin. Parts of the northern domain are covered by more widespread siliciclastic sediments. Differences in the two domains reflect not only variation along strike in time of orogeny but also a range of structural style from large-scale cratonward thrusting in the S to wrench faulting in the N.

The worldwide active middle/late eocene geodynamic episode with peaks at ±45 and ±37 m.y. B.P., and implications and problems of orogeny and sea-floor spreading

Two remarkable geodynamic events in earth history at ± 45 and ± 37 m.y. ago, corresponding to the early and late Pyrenean orogenic phases of Middle and Late Eocene age are described in this paper. Based on numerous data, each of these events is manifested by a set of many various worldwide geologic activities, such as orogenic shortening, granodioritic plutonism, regional metamorphism, change in rate or direction of sea-floor spreading, and global marine regression. These activities shed light on the kinematic relation between plate motions and orogeny because they are widespread and coeval. According to the plate tectonic theory, mountain building is attributed mainly to three types of convergent plate motions: collision, subduction, and obduction. However, an extensive orogenic process does not occur randomly and locally, and does not proceed diachronously by steady plate motion or subduction. The data presented here indicate short duration and synchronism of 1. (a) worldwide orogenic deformations at specific times and 2. (b) abrupt changes of plate motion during the orogeny. In this paper it is shown that there were two geodynamic peaks (±45 and ±37 m.y. ago) which involved more than 80 separate processes of displacement. Such a major reorganization in the plate tectonic pattern reflects a turning point in the geotectonic history. The generally steady, in several oceans variable sea-floor spreading on the one side and the episodic orogenic compressions correspond neither temporally nor kinematically. The two types of movement represent dissimilar kinematic actions. Ocean-floor spreading and orogeny are two different mechanisms that alternate in earth history. It is not the long-term sea-floor movement but a short-term readjustment in the plate tectonic pattern that is related to orogeny. The normal, continuous sea-floor spreading becomes disarranged; its motion is mainly slowed or stopped at times of orogeny which is discontinuous, pulsatory and of short duration. The driving forces of the two processes are different, as is apparent from the contrasting rates of motion. The essential prerequisite for crustal shortening during alpinotype viscoplastic deformation seems to be a worldwide penetrative remobilization of continental marginal zones. Due to the loss of rigidity, the bordering plates then converged. The associated migmatization and granitization point to a thermal origin of this crustal mobilization. Episodic remobilization and folding of continental margins are the expression of such an endodynamic pulsation, released by processes in the earth's interior.

Geodynamic Peaks in Alpinotype Orogenies and Changes in Ocean-Floor Spreading During Late Jurassic-Late Tertiary Time

Modern data indicate that peaks of tectonic displacement alternate with relative tectonic quiescence and that dates of changes in plate motion coincide with times of orogeny. These relations seem to be substantiated by contemporaneity of major discontinuities in seafloor spreading and widespread angular unconformities related to mountain building. Examples are the spreading discontinuities 112, 77, 40, and 10 m.y. ago which are coeval with intense orogenic phases. They are turning points in geotectonic development of the earth--major orogenies occur contemporaneously with first-order readjustments in the plate-tectonic pattern and are reflected in sea-level changes. Thus a close kinematic relation of the processes is suggested. Evidently, orogenic paroxysms are geneticall associated with episodic reorganizations in direction and rate of plate motion. Alpinotype mountain building occurred along mobile continental margins of plates as soon as these were affected by intense compressive orogenic stress caused by a change to convergent interplate motions. Thus, phases of geodynamic activity become apparent in the history of lithospheric plate motions. The specific timing of these phases is an essential geologic parameter and base for further reproduction of plate-tectonic evolution in time and space.

Timing and Coordination of Orogenic, Epeirogenic, and Eustatic Events

The Devonian-Mississippian Antler Orogeny is analyzed and reasons are advanced to show that its movements were felt all around western and Arctic North America. The Antler Orogeny began in the Franklinian Geosyncline during late Early Devonian time and became pervasive in all Arctic regions by the beginning of the Late Devonian. Antler erogenic events migrated southward during the Devonian and reached a climax along the whole span of continental margin, from Ellesmere Island to California, at about the beginning of the Mississippian. The Acadian Orogeny of eastern North America involved deformation of similar timing, suggesting that the two named orogenies are mirror-image events of a single master orogeny. The timing of the three other major North American orogenies of the Paleozoic and Mesozoic is analyzed more briefly. During the Middle Ordovician to Cretaceous interval, the cratonic interior of North America underwent four major onlap-offlap cycles of sedimentation called sequences. Evidently orogeny, epeirogeny, and eustasy act in concert in response to the same driving mechanism, because the timing of orogeny in the geosynclines and of the spread of marine waters to their maximum extent on the cratonic interior is found to coincide with remarkable accuracy during three of the four orogenies, and to be permissively in accord with this correspondence of timing in the fourth. The name “Antler Effect” is suggested for this fundamental relation. Because eustatic sea-level fluctuations are inadequate by themselves to explain the cyclic nature of Permo-Carboniferous sediments of the North American cratonic interior, consideration of the Antler Effect suggests pulsating orogenic movements at the continental margins during that time. In terms of plate tectonic theory, the North American and the European and African plates, juxtaposed during the Carboniferous-Permian, still must have been subject to the driving forces that brought them together, resulting in alternating compressional and relaxatory movements, offering an explanation of the diastrophic theory for the origin of cyclothems. Interpretation of orogeny by investigation of the cratonic sedimentary sequences that are deposited in concert requires a view of orogeny as a long-lasting series of tectonic events separated by short anorogenic times in the geosynclines—a concept at odds with those offered up o t this time. If orogeny is the result of plate convergence, then transgression of epicontinental seas occurs when plates move. Short anorogenic interludes, corresponding to times of regression, appear to occur when the active vectors of the plate-driving force are reorienting. Eustatic sea-level fluctuations, resulting from the activity of oceanic rises, and epeirogenic warping of the continents, acting together, can explain the timing and paleogeographic patterns of the transgressive-regressive cycles on the continents. Because orogeny can occur simultaneously on opposite sides of a continental block, the driving mechanism for plates must involve processes which are independent of the plates themselves.

Petroleum Exploration in Western United States in Light of Principles of Comparative Tectonics: ABSTRACT

Worldwide comparison of tectonic elements shows some elements to be abundantly petroliferous, some to be only partly petroliferous, and others to be nonpetroliferous. Thus, an understanding of comparative tectonics is, or should be, the basis for petroleum exploration. In the western United States, some of the major tectonic elements may be classified as craton, shelf or foreland, miogeosyncline, eugeosyncline, and postorogenic basins. These features are temporal as well as spatial. Their character and distribution principally control the accumulation of petroleum. The formation of the Cordilleran eugeosyncline was characterized by intense folding, thrusting, regional metamorphism, and emplacement of ultrabasic to granitic bodies; the eugeosyncline is essentially barren of petroleum. The Cordilleran miogeosyncline typically has flat thrusts of many miles of displacement, pronounced folds, and rocks of regional metamorphic tones near the base of the sedimentary section. Intrusives are common, but most are small. This region is not presently favorable for petroleum exploration because of extreme disharmony of structures above and below the thrusts. The Rocky Mountain shelf or foreland is characterized principally by vertical tectonics with horizontal End_Page 212------------------------------ adjustments. Some complex structural and stratigraphic problems occur, but this region generally has been favorable for exploration. Postorogenic basins developed on the deformed geosyncline and shelf commonly are petroliferous, especially those along the Pacific Coast. Thorough knowledge of the time of orogeny is essential in exploring these basins. Comparative tectonics should be fundamental in the thinking of exploration petroleum geologists. End_of_Article - Last_Page 213------------

Paleozoic Facies from the Miogeosynclinal to the Eugeosynclinal Belt in Thrust Slices, Central Nevada

Research Article| May 01, 1964 Paleozoic Facies from the Miogeosynclinal to the Eugeosynclinal Belt in Thrust Slices, Central Nevada MARSHALL KAY; MARSHALL KAY Dept. Geology Columbia University, New York, N. Y. Search for other works by this author on: GSW Google Scholar JOHN P CRAWFORD JOHN P CRAWFORD Dept. Geology Columbia University, New York, N. Y. Search for other works by this author on: GSW Google Scholar Author and Article Information MARSHALL KAY Dept. Geology Columbia University, New York, N. Y. JOHN P CRAWFORD Dept. Geology Columbia University, New York, N. Y. Publisher: Geological Society of America Received: 01 Feb 1960 First Online: 02 Mar 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Copyright © 1964, The Geological Society of America, Inc. Copyright is not claimed on any material prepared by U.S. government employees within the scope of their employment. GSA Bulletin (1964) 75 (5): 425–454. https://doi.org/10.1130/0016-7606(1964)75[425:PFFTMT]2.0.CO;2 Article history Received: 01 Feb 1960 First Online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation MARSHALL KAY, JOHN P CRAWFORD; Paleozoic Facies from the Miogeosynclinal to the Eugeosynclinal Belt in Thrust Slices, Central Nevada. GSA Bulletin 1964;; 75 (5): 425–454. doi: https://doi.org/10.1130/0016-7606(1964)75[425:PFFTMT]2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract The Toquima Range, in the center of Nevada, has a remarkable set of thrust sheets of Paleozoic rocks that are displaced by Tertiary high-angle faults; these are mapped and described. Stratigraphically, the sequences in the successive slices when reconstructed show that the lower Ordovician rocks graded progressively from carbonate rocks on the east to argillites with volcanic interbeds on the west; clean quartzites in the latter must have originated to the east and been carried along the depositional trough. Upper Ordovician and Silurian rocks show an island belt of little or no subsidence between a carbonate trough on the east that subsided a mile or so, and an argillite- and chert-bearing belt on the west. The Ordovician stratigraphy is notable in having a fine section of early medial Ordovician fossiliferous carbonate rocks, the type section of the “Whiterock stage,” and representative graptolite zone successions in more westerly slices. Silurian has graptolite-bearing shales in several sequences, some carbonate rocks in the easterly ones. The Devonian limestones are notable in having brachiopods such as Septatrypa, Dubaria, and “Vagrania,” distinctive of Gedinnian in central Europe, previously unrecognized in North America; in the section of greatest span of disconformity, Devonian rocks lie on low Ordovician rocks.The western belts show angular unconformity of Carboniferous sediments on lower Paleozoic rocks; as Carboniferous rocks are cut by thrusts, at least two times of orogeny are indicated. The area is not suited to determination of the time of emplacement of the allochthon, lower Paleozoic argillite-chert-volcanic rocks, on parautochthonous and autoch-thonous sequences, but the more westerly thrusts are younger than those separating the more easterly slices. The thrust faults require crustal shortening of scores of miles although not necessarily in the basement; the implications of crustal gliding are considered. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.

EARLY CENOZOIC VERTEBRATE PALEONTOLOGY, SEDIMENTATION, AND OROGENY IN CENTRAL WESTERN WYOMING

Study of the early Cenozoic Hoback formation adds detail to the Laramide history of central western Wyoming. The recently discovered late Torrejonian, Battle Mountain vertebrate faunule, low in the formation, includes a new condylarth, Tetraclaenodon transitus. Additions to the intermediate Dell Creek faunule include a new insectivore, Elpidophorus minutulus. Additional mammals from three other localities are described. In combination with earlier studies, stratigraphic thickness, faunal ages, and faunal levels provide estimates of sedimentation rates and times of orogeny. The Hoback formation is a thick deposit of fluviatile, palludal, and lacustrine materials that accumulated in a subsiding orogenic trough. Sedimentation was very rapid, probably beginning and accelerating in Torrejonian, culminating during late Torrejonian, then decelerating during Tiffanian, Clarkforkian, and Graybullian times prior to a late phase of orogeny. Sediment was derived locally from western, mid-Laramide highlands which began to rise in the early Torrejonian; the uplift culminated between the middle and end of the Torrejonian. Orogenic phases were relatively brief but intense. The area of deposition was much lower, forested, temperate, humid, locally swampy with some lakes, and largely inhabited by a forest-dwelling mammalian fauna. The Cliff Creek thrust which overrode the Hoback formation is internally complex, with distinct fold-fault sets trending parallel with, perpendicular to, or acute to the thrust trace. Fold axes in the overridden western part of the Hoback formation roughly parallel the thrust trace and are concealed locally beneath the thrust. Local deformation severely distorted the conglomeratic materials in the formation.

Some Characteristic Structural Types in Eastern Asia and their Bearing upon the Problem of Continental Movements

As a result of wide recognition in recent years of extensive overfolding and overthrusting, it seems to have become generally admitted that continents have actually moved horizontally in times of orogeny; but the problem as to how and to what extent such horizontal movements were effected has continued to be an irritating cause for heated disputes and also a fertile ground for wild speculation. In making the present attempt to attack this controversial problem, it is not intended to deal with the merits or demerits of the several species of theories or hypotheses connected therewith, but simply to direct attention to certain groups of geotectonic phenomena found in Eastern Asia and elsewhere, and also to the mechanism responsible for their production as may be attested by experimental means. In this way it is hoped that mere speculation may be eliminated.