Epeirogenic Movements Research Articles

The Basal Rocks of the Tertiary at Uloa, Zululand, South Africa

AbstractAt Uloa in Zululand a nodule bed is the basal formation of a thin group of Tertiary sediments that rests on nearly horizontal Senonian silty mudstones. It contains mammillary, botryoidal, and cylindrical nodules, remanié Lower and Upper Cretaceous mollusca all ferruginized and partly pyritized, silicified Cretaceous wood, worn Tertiary sharks' teeth, and cetacean bone, phosphatized nodules of both Upper Cretaceous and Victoriella-bearing Eocene, and Tertiary glauconitic sandstone pebbles dated at 55 million years.A coquina-like limestone (“Pecten Bed”) overlies the irregular upper surface of the nodule bed disconformably. Consideration of some of the megafossils, the absence of larger Foraminifera, and the presence of Orbulina universa suggest that the “Pecten Bed” is Middle to Upper Miocene in age.Alternations of coarse and fine grained calcarenite layers that overlie the “Pecten Bed” disconformably, may be of youngest Miocene age.The nature of the Tertiary rocks suggests shallow water sedimentation from the Eocene to latest Miocene, with several periods of transgression and regression, and slight epeirogenic or eustatic movement only.

General Outlines of Epeirogenesis and Sedimentation in Region Between Safaga, Quseir, and Southern Wadi Qena Area, Eastern Desert, Egypt

The Egyptian region of the Red Sea depression attained its present configuration primarily as a result of a series of epeirogenic movements. The area between Quseir, Safaga, and the southern part of Wadi Qena was subjected to a series of alternations between major faulting and regional uplift. Structurally, the basement complex of the Red Sea mountain range (west side of Red Sea) constitutes a major horst with a general Erythrean structural direction (northwest-southeast). East of the horst, toward the Red Sea coast, is a group of step faults, ranging in age from post-early Eocene to Pleistocene-Recent. These main faults were shoreline zones during periods of marine sedimentation. The whole area was subjected to successive uplifts, forming an anteclise whose axis parallel d the present Red Sea mountain range.

A CRITICAL REVIEW OF SEA‐LEVEL CHANGES IN EASTERN AUSTRALIA SINCE THE LAST GLACIAL

AbstractAn outline of sea‐level changes is presented, based on field work, bore‐log data, radiocarbon analyses, and a review of the literature. The sequence of eustatic changes, during and since the Pleistocene Epoch, is obscure in Australia, as elsewhere. Evidence suggests that the sea rose rapidly from 17,000 until 6,000 B.P., and that some deltaic plains and coastal depositional features along parts of the New South Wales and Queensland coasts formed since approximately 5,000 B.P. In the areas studied, there is not sufficient evidence to support a lo‐foot higher sea‐level which has been reported in Australia and attributed to a post‐glacial thermal maximum. A possibility of slight epeirogenic movement is considered in attempting to explain some coastal features in southern New South Wales.

MAGNETIC PROVINCES OF LAKE HURON AND ADJACENT AREAS AND THEIR GEOLOGIC SIGNIFICANCE

A regional magnetic survey was conducted on Lake Huron, Georgian Bay, and land adjacent to them in Southwestern Ontario, Manitoulin Island, and Eastern Michigan. Study of its results indicates that the origin of the magnetic anomalies lies within the Precambrian basement complex and that the surveyed area is divisible into seven magnetic provinces. Anomaly trends are used to outline and extend the Grenville Front southward across Lake Huron into Michigan. There is evidence that structural trends within the basement near the southeastern part of Lake Huron may have localized the effects of epeirogenic movement during Paleozoic time and influenced the distribution of sediments and position of reefs.

Structural Trends in Canadian Shield

A description of structures in the exposed Precambrian rocks of the Canadian shield may be of some assistance in understanding the basement structures beneath the surrounding Phanerozoic cover. The shield is divided into a number of structural provinces and corresponding orogens. These differ from one another in age and, in each of the regions, structural trends are described in relation to the orogeny or orogenies responsible for their development. As a rule, the trends are so complex and intricate that they cannot be projected for useful distances beneath the surrounding cover. Locally, Precambrian fault scarps projected from the shield had an influence on depositional features in the overlying rocks. The orogens themselves form structural units of large size and, espec ally along their contacts with one another, possibly has some influence in controlling epeirogenic movements producing basins and highs in the cover.

Stratigraphic Nomenclature of Iranian Oil Consortium Agreement Area

The stratigraphy and correlation of Triassic to Plio-Pleistocene sediments within the Iranian Oil Consortium Agreement Area are discussed. Rock-stratigraphic units are named and defined. These are correlated with the Iraq, Kuwait, and Saudi Arabian stratigraphic successions. The Agreement Area, situated northeast of the Arabian shelf and including part of the Zagros orogenic area, has been the site of more or less continuous sedimentation from Triassic to Plio-Pleistocene time. Regional disconformities occur at the top of the Aptian, the Cenomanian-Turonian, the Cretaceous, and the Eocene. A major angular unconformity produced by Mio-Pliocene folding occurs at the top of the Fars Group. Carbonate and shale deposition controlled by epeirogenic movements dominated until Late Cretaceous time when movements within the Zagros area began to influence sedimentation. Upper Cretaceous, Paleocene, Eocene, and Oligocene deposits are characterized by sharp facies and thickness changes as a result of orogenic movements in the Zagros area. Following deposition of the O igocene-lower Miocene Asmari Formation the Agreement Area was part of a trough trending northwest-southeast. After initial evaporitic and marine phases, this trough was filled by clastics derived from the rising Zagros Mountains on the northeast. Conglomerates of the Bakhtyari, deposited unconformably upon the Fars Group, mark the end of this basinal filling.

Geological History of Central and South-Central Montana

Central Montana has had a complex structural and sedimentary history, especially in the area of the present-day Central Montana uplift. Precambrian and Cambrian subsidence was accompanied by the deposition of more than 13,000 feet of clastics in an east-west-trending trough roughly coincident with the present-day uplift. Pre-Devonian uplift and erosion took place after stable depositional conditions during Ordovician time. Ordovician strata have been eroded from the western half of the study area. Silurian beds are absent from the entire study area. The Central Montana uplift area remained high during Early, Middle, and part of Late Devonian time. Upper Devonian rocks lap onto the uplift, and uppermost Devonian sediments finally covered the area. Pre-Mississippian uplift and erosion removed latest Devonian carbonates and shales completely from a large area of the uplift. The Mississippian System is composed of the carbonate-evaporite Madison Group and clastic Big Snowy Group. Stable conditions prevailed through most of Madison deposition, but central Montana began to subside in late Madison time. Distribution of the Big Snowy Group was restricted by continued subsidence which downwarped central Montana into a synclinorium. Early Pennsylvanian streams draining eastern Montana cut valleys in the Central Montana trough. These valleys were filled, as the streams attained old age, primarily with sandstones and shales derived from the underlying Big Snowy Group. These stream-channel deposits, comprising the lower member of the Tyler Formation, contain the major reservoirs of central Montana. Middle and Upper Pennsylvanian sediments covered central Montana, but all of the Upper Pennsylvanian was eroded before Jurassic time. Pre-Jurassic folding accentuated Mississippian structure. During Jurassic time uplift occurred in the Belt Mountain area at the west. Jurassic strata lap onto this high and thicken regionally eastward and in the Central Montana trough area. Lower Cretaceous deposition was controlled by uplift at the south. These sediments thicken from south to north. The Laramide orogeny upwarped the old trough to form the Central Montana uplift and generally folded the old synclines into anticlines as, for example, at the Sumatra trend. Differential epeirogenic movements, which probably resulted from isostatic adjustment of basement fault blocks, caused the down-up-down-up movements of central Montana. The wedging and truncation of Ordovician, Devonian, Mississippian, and Pennsylvanian reservoir beds created numerous prospects for oil and gas in and around central Montana. Zones of stratigraphic changes in the Pennsylvanian, Jurassic, and basal Cretaceous are also prospective. The area should be rewarding to the explorationist.

Quaternary Geology of Chile: Brief Outline

Research Article| March 01, 1964 Quaternary Geology of Chile: Brief Outline KENNETH SEGERSTROM KENNETH SEGERSTROM U. S. Geological Survey, Federal Center, Denver, Colo. Search for other works by this author on: GSW Google Scholar Author and Article Information KENNETH SEGERSTROM U. S. Geological Survey, Federal Center, Denver, Colo. Publisher: Geological Society of America Received: 14 May 1963 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 (3): 157–170. https://doi.org/10.1130/0016-7606(1964)75[157:QGOCBO]2.0.CO;2 Article history Received: 14 May 1963 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 KENNETH SEGERSTROM; Quaternary Geology of Chile: Brief Outline. GSA Bulletin 1964;; 75 (3): 157–170. doi: https://doi.org/10.1130/0016-7606(1964)75[157:QGOCBO]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 Quaternary deposits of Chile are generally classified according to their mode of deposition and the physiographic province in which they occur. Lacustrine, fluvial, mudflow, and eolian deposits occur in the Cordillera de la Costa, Central Valley, Altiplano, Cordillera de los Andes, and in Magallanes. In addition, deltaic and terrace deposits occur in coastal areas, and glacial deposits in the Central Valley, Cordillera de los Andes, and Magallanes.Quaternary volcanic deposits are present in all physiographic provinces, although in the Central Valley, Cordillera de la Costa, and along the shore of the Pacific they are mostly water-laid tuffs. Flows and pyroclastics are distributed throughout large areas of the Altiplano and the Cordillera de los Andes, and in a few isolated areas in Magallanes. The composition of the Quaternary tuffs of Chile ranges from rhyolitic to basaltic, but the lavas are basaltic or andesitic.The deposits have been very little warped or tilted, but they have been affected by displacements of fault blocks and by epeirogenic movements. The net results of epeirogeny have been general uplift of the coast north of Puerto Montt and general subsidence to the south. 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.

Eustatic Control of Major Cyclic Changes in Jurassic Sedimentation

AbstractEvidence is sought to prove, with reference to five examples, that major cyclic changes in Jurassic sedimentation have been controlled by eustatic rises and falls of sea level. Abrupt variations suggestive of pronounced deepening of the sea in areas of marine sedimentation in Europe are correlated with extensive marine transgressions in widely separated parts of the world. A connection is recognized between eustatic movements and evolution and migration of the invertebrate fauna, and relationships between eustatic and local, epeirogenic movements outlined.

General Tectonics and Paleozoic Stratigraphy of the Delaware Basin of West Texas: ABSTRACT

The pre-Morrow sediments of the Delaware basin were deposited uniformly over a cratonic shelf in a marine environment. During early Morrow time an orogenic movement began which reached its zenith during post-Morrow time. The area was severely eroded and peneplaned. During Strawn and later time, the area began to subside with definite depositional troughs forming. Generally, four facies were deposited simultaneously--the arkose and conglomerate facies on the flanks of the highlands, the lagoonal facies of light-colored limestones and shales in the marginal areas, local reef type or carbonate buildup facies, and the dark-colored basinal facies of limestones, shales, and sands. In some locales, the carbonate buildup facies tended to separate the lagoonal from the basinal fac es. These conditions persisted until late Wolfcampian-early Leonardian time. At this time, the area experienced a broad epeirogenic movement. This movement resulted in a change of regional strike and in many areas resulted in a change in the nature of the sediments being deposited. The sea, during Leonardian time, reached its maximum extent, and for the first time since pre-Morrow time, completely inundated the area. A well defined, barrier type reef developed which separated the light-colored lagoonal facies from the dark-colored basinal facies. The sea began to recede by late Leonardian or early Guadalupian time. Reef growth continued until Ochoan time when an evaporitic basin was forming due to further restriction of the sea. The basin continued to subside as the continent emerged, resulting in a thick evaporate sequence. The end of the Permian was marked by the advent of the Triassic redbeds filling in the basin. This was followed by the complete uplift of the area during late Triassic and Jurassic time. End_of_Article - Last_Page 374------------

Basin-Study Approach to Oil Evaluation of Parana Miogeosyncline, South Brazil

Basin-Study Approach to Oil Evaluation of Parana Miogeosyncline, South Brazil

Structural history of the Beaverlodge area [Saskatchewan

The Precambrian rocks of the Beaverlodge area, northern Saskatchewan, are divisible into 2 broad units, (1) the highly folded and extensively granitized Tazin group unconformably overlain by (2) the synclinally folded Athabasca series. These rocks are cut by 3 major faults, and evidence is presented to show that 2 of these, the St. Louis and ABC faults, are probably extensions of the same break despite a bend of 80 degrees between the 2 prolongations. Age of faulting is discussed and it is concluded that much, if not all, of the fault movements occurred in post-Athabascan time. A method is described by which quantitative estimates of the net-slip on the St. Louis-ABC fault are calculated. Movement is normal, the net-slip roughly 4 mi. A minimum normal dip-slip component of movement on the Black Bay fault is found to be of the same order of magnitude. A 4-stage tectonic history of the area is presented in which 2 periods of crustal shortening alternate with regional, then localized epeirogenic movements. Wherever possible, idealized block diagrams are used to illustrate tectonic events. A table summarizes the tectonic history of the area.

Pre-Desmoinesian Isopachous and Paleogeologic Studies in Central Mid-Continent Region

Major tectonic features of the central Mid-Continent area are outlined and their relation to present thickness and distribution of pre-Desmoinesian strata is discussed. Cambro-Ordovician Arbuckle group thickens southward from zero along the Nemaha and Central Kansas uplifts to nearly 7,000 feet in southern Oklahoma. The Simpson, with maximum thickness of 3,000 feet in southern Oklahoma, thins northward by convergence and overlap of younger units to extinction in northwestern Kansas. Viola-Fernvale thins northward from 1,500 feet in Anadarko basin to 200 feet in southern Kansas, and thickens to 400 feet in Salina basin. The Sylvan-Maquoketa is limited to two areas, one in Oklahoma, the second in northeastern Kansas. Maximum thickness in Oklahoma is 600 feet, in Kansas about 150 feet. Distribution of Hunton resembles that of Sylvan; maximum thickness exceeds 1,500 feet in Oklahoma and 650 feet in Forest City basin. Woodford-Chattanooga lies with regional unconformity on units from Precambrian through Hunton. A 600-foot maximum is postulated for the Anadarko basin; 50-100 feet covers eastern Oklahoma and Kansas. Mississippian limestones are widespread with 4,000 feet in Anadarko basin, 1,600 feet in Hugoton embayment, and zero in northern Kansas. Lower Pennsylvanian Springer is limited to a narrow belt in Anadarko and McAlester basins with maximum of 4,000 feet near Ardmore. Overlying Morrow overlaps Springer, reaching maximum of 1,500 feet in McAlester basin and more than 4,300 feet in Anadarko basin. Distribution of Atoka resembles that of Morrow with 5,000 feet maximum in the Anadarko basin and approximately 8,000 feet in the McAlester basin. Widespread Desmoinesian sediments rest with marked unconformity on Atokan and older rocks. Epeirogenic movements were mild throughout early Paleozoic with geosynclinal development in southern Oklahoma. Eustatic changes produced major unconformities and offlap-overlap relations. Strong warping occurred in post-Hunton, pre-Chattanooga time. Major orogenic movements are post-Mississippian, pre-Desmoinesian with maximum movement in late Morrowan. Final structural development took place in late Cretaceous and early Tertiary. Throughout much of Paleozoic time, the axis of maximum deposition in southern Oklahoma paralleled the Wichita-Amarillo trend in the Wichita embayment.

Mid-Carboniferous sedimentation in the Midland Valley of Scotland

Variations in thickness of mid-Carboniferous strata in the Midland Valley reflect variations in the original pattern of subsidence. This pattern is thought to be deep-seated in origin and probably related to the Variscan orogeny. Variations in sedimentation facies in space and time suggest the operation throughout Carboniferous times of an epeirogenic movement with at least two orogenic episodes. It is suggested that the Carboniferous strata were deposited in a delta-flank depression, the rhythmic character of the succession being due to alternating phases of abundance and scarcity of clastic detritus superimposed on a history of more or less continuous subsidence.

Polar Wandering, a Random Walk Problem

IT has often been supposed that due to redistributions of mass the body of the Earth as a whole has shifted relative to its rotational axis, which has remained fixed relative to the Sun. It is convenient to think of this as movement of the pole over the surface of a fixed Earth. Since the Proterozoic the pole appears to have been displaced by as much as 90° of arc to its present position. Orogenic or epeirogenic movements and ice-cap melting or formation with the attendant fluctuations in sea-level are usually cited as possible causes of polar wandering. Darwin1 and Kelvin2 first discussed the dynamic stability of the Earth. Gold3 and Munk4 have recently re-examined the problem and have concluded that such large displacements of the pole could be a consequence of such geological activities.

Reflexions sur les bases du Quaternaire marin

Abstract Both eustatic changes of level and tectonic deformation are responsible for the present position of Quaternary marine deposits. Variations due to retreat of the glaciers, epeirogenic crustal movements, isostatic adjustment, and other processes are discussed. Although the stable plateau region of Morocco has been subjected to slight epeirogenic deformation and therefore cannot be used, as was hoped, as an absolute record of eustatic fluctuations in the early Quaternary, it nevertheless is a particularly favorable place to study glacioeustatic (climatic) pulsations. Six such pulsations have been identified so far.

Paleozoic Stratigraphy and Oil Possibilities of Kaiparowits Region, Utah

The Kaiparowits region, as defined in this report, covers more than 8,500 square miles in southern Utah. It is essentially a part of a great platform area between the Paradox basin on the east and the Great basin on the west. The Kaibab and Circle Cliffs upwarps, separated by the Kaiparowits basin, are the major structural elements in the region. Cambrian, Devonian, Mississippian, Pennsylvanian, and Permian sedimentary units are present in the subsurface, of which only the Permian is exposed. The lower Paleozoic strata are characteristic products of marine sedimentation on a broad platform bordering the Cordilleran geosyncline. Epeirogenic movements prior to the deposition of the Devonian, and again before Pennsylvanian beds were laid down, were responsible for regional unconformities in pre-Pennsylvanian rocks. Commencing in the early Pennsylvanian, the Kaiparowits region underwent mild orogenic activity related to the ancestral Rockies. The Kaibab and Circle Cliffs uplifts became positive at this time, profoundly affecting sedimentation in the Pennsylvanian strata in a westwardly direction. Continued uplifting caused complet withdrawal of the seas, and in later Wolfcampian time sand dunes swept across most of the region. In Permian Leonardian time the seas again encroached from the west, effecting the deposition of the Toroweap evaporites in a basin in the vicinity of the present Kaiparowits downwarp. The Toroweap passes into a sandstone facies toward the north and east, and is closely related to the Coconino and White Rim sandstones. Equivalents of the Coconino sandstone are found throughout the region, but they occupy only a small interval in the thick sandstone sequences found in the Permian of east-central Utah. The Kaiparowits region has remarkably few major faults except in the western part. A number of anticlinal features exist that have not been drilled for oil or gas, and stratigraphic conditions are favorable for petroleum production at many localities.

Stratigraphy and geological history of Eastern Venezuela

Eastern Venezuela is divided into three geologic-geographic provinces: The Guayana shield in the south; the Eastern Venezuelan basin in the central part; and the mountains of the Serrania del Interior and Cordillera de la Costa (Caribbean Cordillera) in the northern part. The stratigraphy and geological history are discussed, as reflected by rocks of presumably pre-Cambrian, ? Triassic-Jurassic, Cretaceous, Tertiary and Quaternary ages. From the Cretaceous onward, Eastern Venezuela north of the Guayana shield and east of the El BaUl swell, forms part of a geosyncline, the axis of which shifted southward during its history. The position of this axis governed deposition and character of the sediments, which become more marine from south to north and from west to east. Orogenic and epeirogenic movements, particularly during Miocene and Pliocene time, transformed the Eastern Venezuelan sedimentary basin into two structural basins, namely the Maturin basin on the east and the Guarico basin on the west.

Rhyolitic Tuff Flows in Southern Peru

The numerous and widespread sillar deposits in the western Andes of southern Peru are rhyolitic tuff flows which are not welded. Two types may be easily distinguished by color in the field. One, a salmon-colored sillar, is composed largely of minute glass shards and pumice fragments and contains small amounts of oligoclase and biotite and, rarely, quartz. The other, a white sillar, is relatively free of hematite colorant, is hard, and consists largely of secondary axiolitic and spherulitic growths of potash feldspar and (rarely) tridymite with relatively little glass. The white sillar contains quartz, oligoclase, and biotite fragments. Both types of sillar contain foreign material, mostly andesite, probably from the vent walls. Five chemical analyses of sillars from the Arequipa region show remarkable uniformity, regardless of color or degree of recrystalliza-tion, and closely approach the composition of average rhyolite. Sr, Li, Rb, and Cs are present in amounts typical of rhyolitic and granitic rocks. In the upland valleys of Apurimac and Cusco departments single rhyolitic tuff flows have been traced for 20 miles. These sillar deposits are in remnants of mature valleys which are probably of early Pleistocene age. Youthful streams have cut canyons as much as 2,300 feet below the valleys which guided the course of the tuff flows. Similar relationships hold in the Arequipa region, where many deposits of both salmon and white sillar have accumulated in a broad basin between the Yura and Chili rivers. The sillar deposits all appear to be related to dominantly andesitic volcanic centers. Physiographic evidence suggests that eruption of these rhyolitic tuff flows is connected with relatively sudden epeirogenic movement. Andesitic volcanism both preceded and followed the principal early Pleistocene rhyolitic eruptions. The volume of rhyolitic sillar is small compared to that of andesite flows and pyroclastics.

Stratigraphy of Upper Cretaceous and Tertiary Rocks of Raton Basin, Colorado and New Mexico

A thick sequence of late Upper Cretaceous and Tertiary sedimentary rocks is preserved in the Raton basin. These strata include the Pierre shale, Trinidad sandstone, and Vermejo formation of Late Cretaceous age; the Raton formation of Late Cretaceous and Paleocene age; the Poison Canyon formation of Paleocene age; the Cuchara amd Huerfano formations of Eocene age; and two newly defined formations, one probably Oligocene and the other probably Miocene in age. These rocks record some of the stratigraphic and structural events of the Laramide revolution. In the southern Rocky Mountain region the Laramide revolution began with epeirogenic movements west of the Raton basin in late Montana time. The epeirogenic movements were followed by at least seven orogenic episodes, as shown by angular unconformities and lithologic features of the sedimentary rocks. During the Eocene the sedimentary rocks of the basin were intruded by igneous magma to form sills, dikes, plugs, stocks, sole injections, and laccoliths.