Sinkholes Research Articles

Neogene fossil plants from derbyshire (England)

This is a preliminary account of the fossil plants which occur in the uppermost clays infilling the sink holes in the limestone of the Southern Pennines of Derbyshire, England. The plants are of Late Tertiary age, most probably Pliocene, and are of more than passing significance in terms of dating the 1,000 ft. (305 m) Southern Pennine surface. There is no positive proof that the upper plant-bearing clays are of similar age to the underlying unfossiliferous clays and sands, though the absence of a clearly demonstrable unconformity suggests that all the sands and clays were laid down during one continuous process. The fossil plants are in the form of wood, seeds, leaves, spores, and pollen grains. The most significant of those plants so far determined are briefly described, and a Tertiary Component (groups found in greatest abundance in European Tertiary deposits) is recognized and its status discussed. It consists of the following fossil form-taxa or living genera: Gleicheniidites senonicus, cf. Podocarpus-type, Cryptomeria, Sciadopitys, Pinus haploxylon-type, Tsuga, Carya, Symplocos, Tricolpopollenites aff. microhenrici, T. liblarensis, and T. aff. parmularius. Results of quantitative pollen analysis show that this component accounts for up to 70% of the total flora, and since most of the forms reach their peak in Pliocene deposits in Europe, such an age is suggested for this Derbyshire flora.

Reef Configurations: Some Causes and Effects: ABSTRACT

It has been assumed that the deep borings on Pacific have confirmed Darwin's theory of coral-reef development which holds that continued subsidence results in the successive appearance of fringing reefs, barrier reefs, and atolls. It is true that the considerable thicknesses of shallow-water carbonates found in these core holes necessitates subsidence; however, it does not necessarily follow that this subsidence has resulted in the genetic succession of reef types advocated by Darwin. The author enlarges on an alternate theory (first presented by MacNeil) and demonstrates that many, if not most, of the shape attributes of modern reefs are fundamentally karst induced rather than growth induced. There is little doubt that the carbonate platforms beneath most modern reefs have suffered some degree of subaerial exposure. This general inference is warranted by the apparent thinness of recent shallow-water carbonate deposits in conjunction with the low stand of sea level during Wisconsin glaciation. Thus it seems logical to conclude that most modern reefs have developed on a karst substrate. The presence of drowned sink holes a few hundred feet deep on several modern carbonate platforms supports this conclusion and, more importantly, suggests a potential for the development of considerable solution relief. Experiments with limestone blocks indicate the feasibility of solution development of the diagnostic cross-section morphology of both barrier reefs and atolls. Tropical karst land forms are suggestive of the same conclusion. All that is required apparently is a large surface area of gently dipping beds bordered on 1 or more sides by a relatively steep slope. The dissolving action of meteoric water differentially lowers the central area relative to that adjacent to the steep slopes and results in a partly or completely rimmed solution basin. Subsequent rise in sea level permits coral colonization of both the solution rim and the residual karst prominences within the basin. The resulting barrier reef or atoll, with its satellite lagoon reefs, is thus formed without recourse to a prior h story of reef development. The attributes of the reefs themselves support this interpretation, and all seem related to the development of a karst solution basin. Thus drowned atolls reflect drowned karst topography; reef passes originate as drainage breaches in the solution rim; faros are a karst product of breaching; peripheral limestone islands are exposures of the fossil drainage divide; and End_Page 865------------------------------ spurs and grooves are expressions of lapies. These karst-induced differences in relief are perpetuated, and indeed accentuated, by reef growth, but reef growth per se has little to do with the resulting configuration. It follows from this hypothesis that similar events should be recorded in the geologic record, and it is therefore interesting to note that facies relations among some supposed fossil reefs are depositionally incompatible unless an intervening period of subaerial exposure is assumed. End_of_Article - Last_Page 866------------

Peat Deposits of Scar Close, Ingleborough, Yorkshire

The interest of the area known as Scar Close, Yorkshire, is evident from the number and variety of investigations which it has provoked. Jones (1965) has considered its geological aspects, Parry (1960) and Sweeting (1966) its geomorphology, and Moisley (1954) emphasized the need for further study in his account of karstic features of similar sites in the Malham area. This paper is the result of an attempt to add to the substantial body of knowledge from a botanical angle using amongst others the technique of pollen analysis. Scar Close (Grid Ref. SD 750773) is situated at the foot of the north-west side of Park Fell near the steep face of Ingleborough in the Craven district of Yorkshire. It lies on a shelf of Great Scar Limestone at a height of about 1000 ft (305 m). The fell is composed of rocks of the Yoredale Series and the boundary of these with the limestone is marked by a row of swallow holes. The limestone itself has formed pavement with well-developed clints and grykes. The rainfall is high with an annual average of about 70 in. (180 cm), but most of it drains down through the grykes and swallow holes into an underground system. Drainage is impeded to some extent on the inner side of the shelf by a layer of glacial drift, and even on the clints which are practically devoid of soil, some surface water is retained in solution hollows. The drift covered area carries a more or less continuous sheet of wet acid bog, but on the exposed pavement there are only isolated patches of peat lying in direct contact with the limestone and it is these 'islands' which are problematic. They may be relics of a once continuous peat cover or have developed independently from a number of centres and still be advancing. In any case it is unusual to find peat situated immediately upon a well-drained basic substratum. The vegetation of the inner and outer areas of the shelf reflects the difference in edaphic conditions (Fig. 1). The drift-covered limestone bears a typical hummock and pool formation with Eriophorum angustifolium,* E. vaginatum, Vaccinium myrtillus, Calluna vulgaris and various Sphagnum species on the hummocks, and a luxuriant growth of S. cuspidatum in the pools. The peat 'islands' on the pavement are much drier and are dominated by Calluna vulgaris and Vaccinium myrtillus with other species such as Convallaria majalis, Geranium sanguineum and Polypodium vulgare. Most of the peat patches are fringed with mosses including Rhytidiadelphus squarrosus, Pleurozium schreberi and Cratoneuron commutatum. Where small pockets of soil have developed on the clints Sieglingia decumbens and Tortella tortuosa have become established, but they are mostly bare except for crustaceous lichens. A few trees of Acer pseudoplatanus, and Fraxinus excelsior are growing in the grykes with bushes of Corylus avellana, but all are comparatively small and rarely exceed 4 m in height. Other plants found in the grykes are * Nomenclature follows Clapham, Tutin & Warburg (1962) for vascular plants and Richards &

A Drainage Map of Mexico

Students wishing to illustrate the distribution of aquatic or riparian organisms frequently cannot find suitable drainage maps of the area of their interests. This is true for Mexico, a region in which biologists of many disciplines are actively working. A drainage map of that Republic is described here so that others who find it suitable for their work may obtain copies. The base used for the map is and Central America, prepared by the National Geographic Society, March, 1953. The scale is 1:3,500,000, about 55 miles (92 km.) to the inch. After the preliminary draft was made, the drainages were checked against the sheets of the Carta Geographica de la Republica Mexicana, scale 1: 500,000, 1957-58. Reference was also made to the Carta Geologica de la Republica Mexicana, scale 1:2,000,000, 1960. For upto-date information on reservoirs (presas), the second edition (1966) of Caminos de was used. This is published by La Compafiia Hulera Euzkadi, S. A., in a most attractive format, and is available at Sanborn's in Mexico City. Outside measurements of the map are 37 inches long and 27 inches wide; actual map size is 351/2 X 26 inches. Drainage detail was designed for reduction to page size (approximately 8 x 51/2 inches), with placement of the map lengthwise on the page. Consequently, some playas, lakes, and reservoirs had to be made larger than they actually are, some streams had to be cut short so that they would not coalesce with adjacent ones on opposite sides of drainage divides, and many creeks and lagunas could not be included. Shoreline features also have been simplified. State boundaries are shown, but some are only approximate. Brackish water lagoons are differentiated from freshwater bodies by a coarser stipple; playas are shown by a dashed outline. Natural lakes and reservoirs have the same stippling. The map was drafted by William L. Cristanelli, with some subsequent modifications by Jeanne Koelling and Martha B. Lackey. My wife, Frances H. Miller, devoted many hours to the tedious checking of drainages, an often frustrating experience since rarely do two maps of Mexico agree in their hydrographic detail. Roger Conant and Rezneat M. Darnell kindly supplied corrections and suggestions for improvement. The Yucatan Peninsula is blank because the outer part (most of Yucatan) has no surface streams and it is impossible to show the numerous steep-sided cenotes (limestone sinks) and funnel-shaped sink holes (aguadas) at the scale of this map; the basal part has neither surface streams nor natural wells (see Handbook of Middle American Indians, 1964, vol. 1:377 and fig. 18, Univ. Texas Press). An attempt was made to show intermittent streams, but this met with only partial success because of scale size and insufficient information. Despite all these difficulties it is believed that the map will prove useful to many. Those using it are urged to let me know of noteworthy errors and omissions. The map is for sale through the Secretary of the Museum of Zoology (see address below) and across the counter. Support from NSF GB 6272X is gratefully acknowledged.

A Microwave Radiometric Study of Buried Karst Topography

Research Article| June 01, 1968 A Microwave Radiometric Study of Buried Karst Topography J. M KENNEDY J. M KENNEDY Space-General Division, Aerojet-General Corp., El Monte, California Author's present address: Ryan Aeronautical Co., 1840 Nasa Blvd., Suite 100, Houston, Texas Search for other works by this author on: GSW Google Scholar Author and Article Information J. M KENNEDY Author's present address: Ryan Aeronautical Co., 1840 Nasa Blvd., Suite 100, Houston, Texas Space-General Division, Aerojet-General Corp., El Monte, California Publisher: Geological Society of America Received: 07 Sep 1967 First Online: 02 Mar 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Copyright © 1968, 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 (1968) 79 (6): 735–742. https://doi.org/10.1130/0016-7606(1968)79[735:AMRSOB]2.0.CO;2 Article history Received: 07 Sep 1967 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 J. M KENNEDY; A Microwave Radiometric Study of Buried Karst Topography. GSA Bulletin 1968;; 79 (6): 735–742. doi: https://doi.org/10.1130/0016-7606(1968)79[735:AMRSOB]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 Theoretical studies and some microwave measurements of soil penetration capabilities suggested that microwave radiometers may be able to detect subsurface voids associated with karst development beneath relatively thick soil cover. However, from a theoretical aspect, it is difficult to model the effects of surface roughness, moisture content, vegetation coverage, and a nonhomogeneous sky. To prove the potential of microwave surveys in locating and mapping subsurface voids, a mobile laboratory unit was used to obtain in situ data. This unit is equipped with passive microwave radiometers operating at 13.4 GHz (2.22 cm), 37 GHz (8.1 mm), and 94 GHz (3.2 mm), as well as geophysical support equipment.An area near the town of Cool, El Dorado County, California, was used to obtain data. This, area is known to have well-developed subsurface karst development and has been surveyed by both the California Highway Department and the California Rock and Gravel Company.The microwave survey showed significant radiometric “cold” anomalies associated with void-space development beneath several tens of feet of soil cover. Detection was positive in almost all cases, evidence of the strong probability that microwave systems may be used to detect and rapidly map karst systems from a remote platform. This will greatly reduce surveying and construction costs in areas where caves and sink holes have developed beneath obscuring soil cover. 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.

Etude petrographique du siderolithique du Lot (gisement de Saint-Martin-le-Redon) (confins du Perigord, de l'Agenais, du Quercy)

Abstract A sink hole in Senonian limestone (southern Perigord, France) yielded a siderolithic deposit of Ludian age (upper Eocene) which consists of a series of poorly stratified clay, sandstone and multicolored sand with interbedded mineralized beds. Results of the petrographic analysis of thin sections made from these rocks show that percolating water attacked the ferromagnesian minerals, potassium silicates and sodic-calcic minerals, modifying their crystallographic texture, contributing to the formation of secondary minerals, and staining the rocks toward the base of the deposit. The consolidation of these minerals by polymorphic silica, itself attacked by the waters, suggests the possible existence of an essentially dry, tropical climate. However, the proportion of amphiboles in the arkoses is noticeably greater than in the sands, sandstones, and kaolinite deposits, thus ascribing a warmer, more humid aspect to the upper Eocene. Oxides are common at the base of the facies, which rests directly on Cretaceous limestones.

Effect of Local Loss of Support on Foundation Design

Investigation of effects of development of small sink holes, excavation for temporary repairs, erosion by groundwater, or compaction resulting from vibrations on local subsidence beneath foundation structures; results of study for beams and slabs that span gaps in elastic subgrade; in order to simplify computations, curves have been prepared that may be used for design.

Effect of Local Loss of Support on Foundation Design

Investigation of effects of development of small sink holes, excavation for temporary repairs, erosion by groundwater, or compaction resulting from vibrations on local subsidence beneath foundation structures; results of study for beams and slabs that span gaps in elastic subgrade; in order to simplify computations, curves have been prepared that may be used for design.

Some Observations on By-Passed Swallow-Holes in the Meuse and Lesse Valleys

Some Observations on By-Passed Swallow-Holes in the Meuse and Lesse Valleys

The Cultural Complexes from the Lagoa Santa Region, Brazil

THE Lagoa Santa region, Minas Gerais, Brazil, has long attracted the attention of the scientific world ever since the Danish naturalist, Peter Wilhelm Lund, announced in the last century the possibility that man in this area was contemporary with extinct Pleistocene animals (Paula Couto 1950). Since then the area has drawn many other investigators, for the sites are numerous and of easy access in the many limestone caves and rock shelters north of Belo Horizonte, the state capital. The majority of reports which have been published on Lagoa Santa, in particular those by the members of the Academy of Science of Minas Gerais, have continued the claim made by Lund that Pleistocene man lived in these caves (Walter n.d.; 1958; Mattos 1946; 1950). Because the conclusions made by these writers have not been accepted universally (Watson 1949; Hrdlicka 1912) a project was initiated in 1956 by the University of South Dakota and the Museu Nacional of Brazil to make further tests in the area1 (Fig. 1). The Lagoa Santa caves and rock shelters are a small part of a large number of caves in prominent limestone masses that in many areas form cliffs in the main valleys and tributaries of the Rio das Velhas and Rio San Francisco in the states of Minas Gerais and Bahia. In the region of Lagoa Santa are many running streams, some of which are partially subterranean, and numerous small lakes and limestone sink holes. The vegetation of the area is mainly of the savannah type of tropical forest, while the climate is of the alternating wet and dry season variety (Koppen's CW type, see Goode 1943:20). Judging by the paintings made in the Lagoa Santa caves the following recent fauna lived in the area: deer, tree sloth, tapir, fox, several varieties of cats, pacas, and marsupials. The limestone masses of Lagoa Santa were deposited during the Paleozoic and hardened into the present-day Bambuhy formation during the Silurian. The geological and climatological history of the Lagoa Santa region has not been investigated or reconstructed in detail by geologists and the interpretation which follows is solely that of the writer's. It is based on personal observation. In addition, the conclusions rest heavily upon comparison with North America, the assumption being that there was a strong correlation in the meteorological cycles in the two continents. (1) During an unknown time in the past when the climate was colder and more humid than at present, perhaps the early Pleistocene, the Lagoa Santa region was covered with extensive lakes. (2) As these lakes rose and subsided wave action and bank erosion cut into the limestone formations, forming sheer cliffs. (3) Caves were cut into the faulted cliffs when the level of the lakes re-

Swallow-Holes in the Mole Gap

Swallow-Holes in the Mole Gap

The Karstlands of Jamaica

fTlHE rough and uneven surface of the country . . . renders it quite impassable; X high peaks, steep hills, ravines, gullies, sink holes, etc. present so many obstacles that this portion of the parish has well earned the appellation of 'terra incognita'.1 # This is part of Sawkins' description in 1869 of the cockpit districts of Jamaica (pp. 195-6), some of the most striking areas of tropical karstf landscape to be seen anywhere in the world. This paper describes the most important characteristics of the Jamaican karstlands, particularly those in the north and centre of the island, including the area known as the Cockpit Country. Jamaica is essentially a mountainous and hilly island. Two-thirds of its area is made up of highly dissected limestone plateaus, varying in height from 1000-3000 feet above sea level. The White Limestone Series upon which these karst areas have developed are Upper Eocene-Lower Miocene in age, with a total thickness, in places, of the order of 2000 feet. The general structure of central and western

A Site at Stump Cross, near Grassington, Yorkshire, and the Age of the Pennine Microlithic Industry

The site described in this paper lies on the Yorkshire Pennines, slightly over 1,200 feet O.D., half a mile north-west of Stump Cross Cavern and five miles east of Grassington (Nat. Grid 082640). The solid rock there is an eastward extension of the Great Scar Limestone, pitted by numerous swallow holes and clothed by a thin and intermittent mantle of clayey glacial drift. Only a hundred yards to the north and half a mile to the south-east of the site the Millstone Grit replaces the limestone at the surface. In the vicinity of the site the vegetation is dominated by Calluna vulgaris and Eriophorum vaginatum growing over a podsol or a shallow, highly humified, peat.

Swallow Holes on the Millstone Grit and Carboniferous Limestone of the South Wales Coalfield

SWALLOW holes or depressions caused by the collapse of underlying caverns are characteristic f ar as underlain by calcareous beds. The junctions of essentially calcareous formations and overlying systems of sharply contrasting lithological character have frequently been described as showing a profusion, or concentrated alignment, of swallow holes or allied forms.1 These generally mark the disappearance points of surface streams into underground courses so that the holes themselves are more attributable to the solution and enlargement of joint planes than to the collapse of pre-existing caverns. Outcrops of looselycompacted arenaceous beds forming cappings to underlying massive calcareous beds are liable to show surface reflections of the caving in of cavern roofs. It is thus normal, especially in areas with horizontal or gently-tilted strata, to find a fair scattering of these depressed features even though the top of the calcareous, cavern-bearing beds is at depths up to 30 or 40 feet. On the North Crop of the South Wales Coalfield, where comparatively narrow and roughly concentric outcrops of Millstone Grit and Carboniferous Limestone consecutively fringe the productive Coal Measures, an apparently anomalous state of affairs exists which appears to be unique. Here the most conspicuous and perfectly developed collapse features, in the form of large swallow holes, are decidedly more numer? ous on the outcrop of the Basal Grit, the lowest sub-division of the Millstone Grit, than on the outcrop of the underlying Carboniferous Limestone within whose beds such features were initiated. At certain points some of these swallow holes are located at distances of more than a mile south of the junction with the Carboniferous Limestone and underlain by a maximum thickness of about 250 feet of Grit beds. To illustrate fully this abnormal development a detailed six-inch survey was undertaken of the distribution of swallow holes and other solution sub? sidence phenomena on the Carboniferous Limestone and Millstone Grit out? crops ranging over a west-east length of 30 miles from the Twrch valley in south-east Carmarthenshire to Blorenge Mountain in north-west Monmouth shire and with a maximum north-south width of 5 miles. The results of this survey have been compounded (Fig. 1) so as to provide in one diagram a distribution picture for the region as a whole. It has revealed a wider acreage more closely pocked with swallow holes than in any other area of the British Isles. Certain sections of this area of survey, where they portray typical or special features of the distribution pattern, have been retained on a larger scale (Figs. 2 and 3). (For Fig. 1 see facing p. 474.) For the most part the Carboniferous Limestone within the limits defined has a vertical thickness of 500 to 700 feet, but in the extreme east there is a rapid diminution so that on Blorenge Mountain it is rather less than 100 feet thick.2

A GUIDE TO THE GEOLOGY OF THE DISTRICT ROUND INGLEBOROUGH

I. Introduction and Topography Ingleborough lies near the boundary between two areas of strongly contrasting scenery, the contrast arising from the differences in the rocks involved and the movements they have suffered. The area to the north-east is dominated by the peaks of Whernside ( 7381 )[1][1], Pen-y-Ghent ( 8373 )[1][1], and Ingleborough ( 7474 )[1][1] (2373 ft.). These rise above a broad shelf, about 1300 ft. above O.D., marking the top of a massive limestone, on which have been developed all the features associated with a “karst” cycle of erosion which has reached a mature stage. Extensive limestone pavements with their characteristic “clints” and “grikes” (Pl. 4), deep sink-holes, such as Gaping Gill ( 751727 ) and swallow holes like Hull Pot ( 823746 , Pl 9, Fig. 1), caves with a wealth of stalactites and stalagmites such as Clapham Cave ( 754711 ) and White Scar Cavern ( 713746 ), natural bridges such as God’s Bridge ( 733764 ) and collapsed caves such as Trow Gill ( 755717 ), all show the solvent action of the disappearing surface water. According to Miss Sweeting (1950), the 1300 ft. shelf is an old erosion surface and an upper series of caves at about 1250 ft. were produced at a time when the water-table lay just below that surface. A lower series of caves at 950 to 1000 ft. belong to a water-table position associated with a rejuvenation stage of the river system while the lowest system of caves belong to the present cycle. The course of the underground drainage was investigated by members of our Society in collaboration … [1]: #fn-1

LIMESTONE WALLS OF OKINAWA

Wall-like ridges of limestone that stand well above the surrounding terrain are an interesting phenomenon on the island of Okinawa. These ridges rim a variety of topographic features, but all are believed to represent the same formative processes. Rimming ridges or walls occur along the banks of streams crossing areas of limestone, along the upthrown sides of faults, around a sink hole, and along terrace edges. The limestone walls of Okinawa are believed to have formed by the cementation, or casehardening, of steep exposures of poorly consolidated limestone, followed by differential erosion which brings the cemented zones into relief. Cementation occurs wherever poorly consolidated limestone is exposed to alternate wetting and drying. It is best developed, however, on steeply sloping exposures where no soil accumulates to hinder drying. Differential erosion results in part from slower solution of cemented limestone, due to its greater density, and in part from accelerated solution in the surrounding soil-covered areas. Rampart walls along the seaward edges of terraces have been described from many Pacific islands and are present on many others. They are believed to be comparable to the walls of Okinawa and all are believed to have been formed under similar conditions.

GROUND-WATER BEHAVIOR IN THE HERSHEY VALLEY, PENNSYLVANIA

The Hershey Valley, part of the Great Valley, is 9 miles east of Harrisburg, Pennsylvania. Beekmantown limestone (Ordovician), striking N. 70° E., and steeply overturned to the southeast, underlies the valley. The Annville Stone Company mines the high-calcium Annville limestone (top of the Beekmantown) 1½ miles northeast of the Hershey Chocolate Corporation plant. For many years 3500 gpm was the normal pumping discharge. Neither industry adversely affected the other nor any of the valley residents. Plans of the Stone Company to mine at lower levels prompted geologic studies by the Chocolate Corporation. One hundred wells and springs in the valley were systematically observed, 12 of the most critical being measured every 2 weeks. For each there was determined the water elevation; water temperature; pH value; ppm of dissolved solids; ppm of the Ca, Mg, PO 4 , SiO 2 , Al 2 O 3 , SO 4 , and Fe ions; and yield in gpm of the springs. Details of ground-water movement were studied by using fluorescein. Water table maps of the valley were periodically made. When the mine began pumping 6500 gpm from lower levels in May 1949, it drastically lowered the ground-water level over an area of 10 square miles, drying up most valley springs and many wells. About 100 sink holes of all sizes developed in the area, endangering life and property. The water-table map of November 1949 showed a huge cone of depression with the apex at the mine. Ground-water levels were successfully restored over a large area when the Chocolate Corporation recharged water to the ground, beginning December 1949.

Erosion Cycles and Limestone Caverns in the Ingleborough District

The ingleborough district has long been famous for its broad limestone plateaux, its deeply cut dales and its swallow holes and caves. The aim of this paper is to discuss the origin of these relief features and to show that a number of pre-Glacial erosion stages can be recognized in the denudation of the area. The district considered forms the south-west edge of the North Pennine highland massif, overlooking the Craven Lowlands, and is dominated by the well-known residual hills of Ingleborough and Pen-y-Ghent which rise to over 2000 feet. From it flow, in a general southerly direction, the headstreams of the Lune, Ribble, Aire and Wharfe, and it lies on the watershed between the Irish Sea and the North Sea.

ORIGIN OF THE FILLED SINK-STRUCTURES AND CIRCLE DEPOSITS OF MISSOURI

Research Article| August 01, 1950 ORIGIN OF THE FILLED SINK-STRUCTURES AND CIRCLE DEPOSITS OF MISSOURI J HARLEN BRETZ J HARLEN BRETZ UNIVERSITY OF CHICAGO, CHICAGO, ILL. Search for other works by this author on: GSW Google Scholar Author and Article Information J HARLEN BRETZ UNIVERSITY OF CHICAGO, CHICAGO, ILL. Publisher: Geological Society of America Received: 21 Apr 1949 First Online: 02 Mar 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Copyright © 1950, 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 (1950) 61 (8): 789–834. https://doi.org/10.1130/0016-7606(1950)61[789:OOTFSA]2.0.CO;2 Article history Received: 21 Apr 1949 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 J HARLEN BRETZ; ORIGIN OF THE FILLED SINK-STRUCTURES AND CIRCLE DEPOSITS OF MISSOURI. GSA Bulletin 1950;; 61 (8): 789–834. doi: https://doi.org/10.1130/0016-7606(1950)61[789:OOTFSA]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 More than 1000 roofless solution cavities, filled with clay, shale, sandstone, coal, hematite, pyrites, galena, sphalerite, barite, and dolomitic debris, lie on the northern and western slopes of the Ozark dome. More than a score of geologists have proposed seven different concepts regarding the genesis of some of these cavities and their fillings. The favored three concepts are: (1) original surface sink holes; (2) collapsed caves; and, (3) gradual subsidence of overlying rocks keeping pace with solutional removal, under saturated conditions, of subjacent calcareous rock. The others are: (4) deposition of fills in unquiet seas; (5) dropping of fill material at intersection of faults; (6) collapse of superjacent filled caves into subjacent empty ones; and (7) localized upward thrust. This paper intends to show that the filled sinks and the circles constitute two different categories of solution cavities. The circles, properly defined, are collapsed caves but only concept (3) can explain the compressional deformations which the fills and cavity walls of the sinks exhibit. 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.

Permo-Triassic geology of south Cumberland and Furness

The Permo-Triassic rocks flanking the Duddon Estuary dip south-westward in three fault blocks defined by major N.N.W. faults downthrowing west. The Zechstein deposits include Brockrams (breccias) accumulated near the old Lake District landmass, passing south-westward into St. Bees Shale and Magnesian Limestone. Still farther from the old shore-line, the limestone gives place to massive anhydrite. Among the Zechstein sediments are grey, plantbearing dolomitic siltstones, possible equivalent to the Hilton Plant Beds and Marl Slate farther east. The Bunter is represented by sandstone (St. Bees) 2,500 feet thick. Evidence is presented to show that in Furness the Bunter overstepped the Zechstein to rest directly on the Carboniferous limestones, and it is suggested that the haematite “sops” of that region originated in swallow holes formed beneath the sandstone. After mineralisation by solutions whose origin is still in doubt, further solution without mineralisation caused collapse and brecciation of the ore-bodies. The Keuper includes grey (Kirklinton) sandstone, overlain by marl with halite deposits. The simplest interpretation of the subsurface geology beneath Walney Island suggests that the halite deposits are lenticular in form, and at different stratigraphical levels. Petrographical descriptions of the sediments and evaporites are included.