Mud Banks Research Articles

Role of Physical Sedimentation in Carbonate-Bank Growth: ABSTRACT

Carbonate mud banks of central Florida Bay contain three types of sediment wedges which provide evidence that pulses of rapid physical sedimentation are a dominant cause for bank growth and migration. Most dramatic are layered to laminated wedges of carbonate mudstone flanking eastern, southern, or western bank margins. Depositional units are 0.5 to 1.5 m thick and compose up to 70% of the existing bank. Units have erosional basal contacts; basal shelly sand grades upward to a layered to laminated mudstone containing no pellets, no burrowing, no seagrass rootlets, and few sand-size skeletal grains. Three features suggest rapid deposition: vertical escape burrows extending upward from the basal sand, vertical smooth-walled water-escape fractures in the lower part, and abundant seagrass blades incorporated into the layers. The second type of wedge is a layered, pelleted mudstone to packstone otherwise similar to that described above. The third type of wedge is a bioturbated, soft-pellet wackestone to packstone as much as 1 m thick and flanking only southern bank margins. It contains horizontal to inclined seagrass rhizomes throughout and has minor autochthonous mollusks. The layered wedges are interpreted to record rapid subtidal sedimentation during rare superstorms (extreme hurricanes), the first type from storms of sufficient violence to destroy most pellets. The third wedge type records persistent lee-side accumulation from lesser hurricanes and winter storms. This deposition, although rapid, is slow enough to be in continuous association with a seagrass-community influence. End_of_Article - Last_Page 547------------

Interstitial Water and Sediment Chemistry of Two Cores from Florida Bay

ABSTRACT The interstitial water and sediment chemistry of cores from two different environments in Florida Bay, mangrove swamp and submerged mud bank, have been analyzed. The interstitial water profiles show that sulfate reduction, along with the resulting ammonium, phosphate, and alkalinity production, is occurring in Florida Bay sediments. However, the sulfate concentration profile is not typical of other anoxic environments, in that the sulfate concentration increases below a depth of approximately 20 cm. The ammonium, phosphate, and alkalinity concentrations all decrease below this depth. It is suggested that these interstitial water profiles might be explained in terms of a balance between the mixing of the interstitial water with the overlying seawater and decreasing rates of organic mat er decomposition with depth. The rates of organic matter decomposition have been measured in laboratory experiments, which indicate that sulfate reduction and ammonium generation are much faster (a factor of 3 to 9 times) between 0 and 10 cm than between 10 and 20 cm. Organic carbon, organic nitrogen, and amino acid profiles show decreases as large as a factor of 2 in the organic content of Florida Bay sediments in the top 60 cm of the sediment column.

Blood respiratory properties of a viviparous amphibian.

BURROWING apodan amphibians (order Gymnophiona) are relatively common in the Amazon River Basin of South America but the physiology of the group has been little studied. The animals are usually fossorial, living burrowed in the mud banks of small tributaries of the main river. The burrows, which they presumably dig, are small and conditions are often both hypoxic and hypercarbic. Animals 0.25–0.75 m long and weighing 100–600 g, found near the air–water interface, were dug out of the mud banks and immediately taken to the laboratory of the research vessel RV Alpha Helix for study. Several species of burrowing apodans occur in the area, but the most common is Typhlonectes compressicauda, the animal used in this study. We report here on the blood respiratory properties of this organism.

Unique Mud Banks, Kerala, Southwest India: GEOLOGIC NOTES

The of Kerala (southwest India), a potential modern analogue of an ancient hydrocarbon-generating environment, are in nearshore shallow water about 10 m deep. Individual banks extend over an area of 25 sq km or more. They are characterized by rapidly accumulating fine-grained silty clay sediments, high organic matter, oxygen-deficient bottom waters, and dense mud suspensions. The muds are thixotropic, and the sedimentary environment suggests conditions suitable for gas generation within the sediments. It is proposed tentatively that thixotropic and gas-generation properties of the sediments, with the waves, keep the mud in suspension and result in the spectacular wave-damping property of the mud banks.

Calcareous crust (caliche) profiles and early subaerial exposure of Carboniferous carbonates, northeastern Kentucky

ABSTRACTSequences of laminated limestones found within thin Carboniferous carbonate strata of northeastern Kentucky were studied to determine their origin and palaeo‐environmental significance. These laminated zones are strikingly similar to Holocene and Pleistocene surficial calcareous crusts (caliche) profiles that occur in various parts of the world.Carboniferous laminated carbonates are associated with shallow marine carbonate units, palaeokarst, and overlying palaeosol zones. A typical laminated profile ranges in thickness from 1 to 2 m and contains brecciated, light olive‐grey to brown micrite that lacks distinctive bedding. Structures and textures common in most profiles include: (1) calcareous and silicious laminae (laminae form diffuse, alternating light and dark bands that generally parallel bedding but often fill fractures and vugs within the rocks); (2) particles (allochems, and micrite and microspar fragments) coated by brown microcrystalline calcite; (3) brecciated texture; (4) circular to elliptical fossil moulds (occur in sinuous patterns and fill fractures within the rocks); (5) large and small scale fracture patterns.Subaerial weathering and vadose diagenesis of carbonate mud banks or islands is suggested as a mechanism for the formation of these Carboniferous calcareous crust profiles. These ‘crusts’ formed by a combination of solution (karsting), brecciation, and soil development that transformed an exposed marine biomicrite (‘host’ rock) into a porous subsoil rubble. Laminated ‘crusts’ and coated particles developed as the result of dissolution and reprecipitation of CaCO3 and SiO3 from the soil and carbonate bedrock.Carboniferous laminated carbonates in northeastern Kentucky are often referred to as ‘algal limestones’ because of their superficial similarity to some modern and ancient algal structures. This study, however, reveals numerous characteristics that can only be explained by diagenesis in a subaerial environment.

The establishment of Spartina in the Tamar Estuary, Tasmania

Spartina anglica was introduced into the Tamar Estuary, Tasmania, in 1947. Initially spread was slow but subsequently rapid. It is capable of colonizing all rock types and sediments available in the estuary but fine sediments provide the most and basalt the least suitable substrate. It colonises all available slopes (10 degrees -28 degrees). As a result of the introduction, mud banks become stabilized and the navigable channel thereby safeguarded. The spread of Spartina has, however, adversely affected some beaches and private jetties.

Facies Types and Depositional Environment of the Sokoman Iron Formation, Central Labrador Trough, Quebec, Canada

ABSTRACT Cherty iron-formations (= ferriferous cherts) have sedimentary textures analogous to the sedimentary textures of limestones; it is possible to define textural rock types analogous to the micrites, intramicrites, oosparites, etc. of limestone classification. The close analogies between limestone textures and the textures of cherty iron formation permit paleogeographic interpretation of Precambrian iron formation by comparison with the textural facies of Recent limestones. The Sokoman Iron Formation of the Central Labrador trough, Northeastern Quebec, Canada, is subdivided in five members on the basis of composition; these can be subdivided in sub-members distinguished by their textural properties. Comparison of the distribution of facies types of the Sokoman Iron Formation with Recent limestone environments suggests deposition in two basically different environments: (1) A lagoonal platform probably composed of rapidly shifting banks of oolitic and intraclastic sand, of mud banks, and of small, lagoonal basins. (2) A basinal environment where relatively monotonous fine grained intraclastic sands, and rocks analogous to micrites were deposited. A narrow domain of oolite shoals separates both environments. Traces of evaporites (length-slow chalcedony and pseudomorphs after gypsum) prove deposition of the Sokoman Iron Formation in a warm and comparatively dry climate.

Paleoenvironmental Patterns in Middle to Lower Upper Cambrian Interval in Eastern Great Basin

In the eastern Great Basin region during the Middle Cambrian and early Late Cambrian a north-trending, near-sea-level shoal separated a deeper water open shelf on the west from a shallow shelf-lagoon. Regression in the late Middle Cambrian (unit K) led to a flooding of terrigenous sand across the continental shelf and the emergence of islands flanked by supratidal and intertidal zones on the shoal. At times preceding and following this event, a lacework of tidal algal mud banks and shallow subtidal basins occupied the shoal. Hydrologic conditions determined the morphology of the stromatolites on the mudbank. Normal supratidal processes were responsible for dolomitization along island shorelines, but the biogenic concentration of magnesium in algal mats, in conjunction with magnesium-enriched brines, accounted for the dolomite in the stromatolites associated with the tidal mudbanks. Dolomitization in the subtidal basins and shelf-lagoon was controlled by bedding and mottled structures of physical and biogenic origin, and was more pervasive in the lagoon. Unit K and its correlatives across the shelf are believed to be time-parallel in that there is little time differential along unit boundaries. On the shoal other algal boundstone units also may be time-parallel and serve as a basis for establishing temporal relations in the eastern Great Basin. Comparison of tidal-subtidal cyclic sequences in the Cambrian of North America and elsewhere may permit the recognition of eustatic and/or epeirogenic events useful in establishing temporal relations on a continental or larger scale.

Paleoenvironments of Phosphoria Formation, Cottonwood-No Water Creek Fields, Washakie County, Wyoming: ABSTRACT

The Cottonwood and No Water Creek fields produce from a common carbonate reservoir formed by a facies change from shelf carbonates on the west to continental redbeds on the east. Production is from the Ervay Member of the Permian Phosphoria Formation. Carbonate sediments of the Ervay are analogous to carbonate sediments of the Persian Gulf suggesting similar depositional environments. Paleoenvironments in the study area were determined by thin-section analyses and include salt flats, mud banks, mud flats, lagoons, and green algal banks. Carbonate sediments were deposited in an embayment on a broad stable shelf bordered by low continental areas on the east and the miogeosyncline on the west. Arid and warm climatic conditions prevailed over most of the area allowing for rapid evaporation in the nearshore areas. Green algal banks developed along sub-hinge lines (or topographic highs) on the shelf. These banks provide the best reservoir conditions and possibly the best production at No Water Creek field. The Ervay throughout the subject area is dolomitized. Dolomitization was penecontemporaneous with deposition and anhydrite precipitation. Chert and collophane are common accessory minerals and increase in percentage westward. Anhydrite increases in percentage eastward. End_of_Article - Last_Page 1392------------

Sedimentary Facies and Distribution of Biota in Coupon Bight, Lower Florida Keys

Coupon Bight is a 9-sq-km bay separated from an offshore Inner Reef Tract by low-lying islands and a bay-mouth bar. Coupon Bight has less wave activity and less complete tidal exchange than Inner Reef Tract waters, and is no more than 250 cm deep. Temperatures and salinities in Coupon Bight are more variable and usually higher than those in waters of the Inner Reef Tract. The harsher environmental conditions of Coupon Bight are reflected in its less diverse biota, compared to that of similar areas in the Inner Reef Tract. Environmental gradients persisting between the various parts of Coupon Bight produce more pronounced faunal variations than are found in the more homogenous Inner Reef Tract. Physical and chemical conditions, sedimentary facies, and biofacies of the bight are closely related. Several major environments can be recognized in Coupon Bight, each characterized by a particular assemblage of organisms. Open bay, nearshore, restricted bay, baymouth bank, and tidal channel environments are present. The unconsolidated sediment of Coupon Bight is mainly autochthonous skeletal debris, with minor contributions washed in from the Inner Reef Tract and from eroded limestone bedrock. The texture of bight sediments ranges from sand to mud, with most of the mud facies found in bank-like deposits associated with thick growths of the marine grass Thalassia. Most of the fine-grained sediment in Coupon Bight is the product of disintegration of coarse shell debris. Fine materials are winnowed out by waves and currents and either trapped on Thalassia covered mud banks or carried out of the bight. The variability of and relations between environments, sedimentary facies, and biofacies that can occur in a small area such as Coupon Bight are clarified by the data collected during this study. As a result, similar variability in shallow-water marine carbonate rocks can be better interpreted.

The Occurrence and Distribution of Crabs in a Jamaican Mangrove Swamp

The zonation of animals and plants in mangrove swamps is often greatly complicated by the structure of the swamps. Developing in sheltered areas, often around river mouths, extensive mangrove swamps are interlaced with drainage and tidal channels, and contain semi-stagnant lagoons, deep mud banks, thickets of mangrove and the occasional island of hot, dry land. The diversity of these features depends on the size of the swamp which, in its turn, depends on the proximity of rivers and the tidal range. A further complication introduced by the proximity of rivers is variable salinity which may also be caused by heavy rain and poor drainage. Workers in mangrove environments (Verwey 1930; Dansereau 1947; Macnae & Kalk 1962; Berry 1963; Macnae 1963, 1966, 1967), while recognizing the existence of faunal zonation, have described this zonation only in a qualitative fashion. Rodriguez (1959, 1963) did not describe zonation within mangrove environments but, in common with Berry (1963), recognized several habitats, each with its characteristic fauna. The only workers who collected quantitative data in mangrove environments (Golley, Odum & Wilson 1962; Rodriguez 1963) did not relate these data to tidal levels. These apparent difficulties were probably due to the complexity of the swamps involved. The swamp chosen for the present investigation avoids many of these difficulties. It is situated some distance from river mouths and is not, therefore, liable to regular salinity change. It is not particularly extensive, the intertidal zone rarely exceeds 150 m in width. The complicating features listed above are almost entirely absent and it is possible to take a straight line transect from low tide level to high tide level without encountering channels, mud banks, lagoons, etc. The zonation of the swamp crabs was, therefore, studied in the conventional way, with transect and quadrat. This investigation showed that the distributions of most of the crab species are related to tidal levels in a way that is similar to the zonation of other types of shore. The investigation also provided information on the microhabitats of the crab species and on the size distributions of the populations of three common species.

Un domaine de sédimentation calcaire : la baie et les keys de Floride et les milieux environnants

FLORIDA BAY AND SURROUNDING AREAS The sedimentary environments of Florida Bay and the surrounding areas are described. They consist firstly of Pleistocene sequence, of Sangamon age, including from East to West coral reefs (Florida keys), Miami oölitic ridge, and bryozoan facies. This sequence has its counterpart in present-time deposits of the Great Bahama Bank. The Holocène formations are, in the same order: the outer living reef; the back reef, both of which forming the reef tract; Florida Bay, in which «lakes», mud banks, and islands are found, all of them consisting of fine calcareous mud supplied for a very large part by a green alga, Penicillus; Cape Sable, in which the quartzose fraction is greater than elsewhere; Whitewater Bay and the Everglades, where recent fibrous peat was laid down above a basal calcitic mud, which in turn rests upon Miami oölite or the bryozoan facies. Lime plays a tremendous part in sedimentation under various forms. Short comparisons are made with other calcareous environments in the tropical and temperate belts.

Distribution of Silicate Minerals in Florida Bay: ABSTRACT

The predominantly carbonate sediments within Florida Bay contain small percentages of insoluble silicate minerals, ranging in our samples from 1.25 to 14.91% by weight. Quartz, chlorite, and montmorillonite compose most of the silicate fraction, with very minor amounts of illite and kaolinite. Clay-mineral distribution can be described by concentration gradients based on two end-member assemblages. A chloritic assemblage dominates in the eastern part of the bay, but declines westward; a montmorillonitic assemblage dominates the western bay and declines eastward. The two clay-mineral assemblages reflect different sources--chlorite from the Atlantic province, and montmorillonite from the Gulf of Mexico province. Shallow and subaerial carbonate mud banks and intervening basi s inhibit mixing waters bearing the two clay assemblages; the result is the relatively abrupt transition from one clay suite to another in the 30-40 mi span of Florida Bay. The clay mineral fractions of similar ancient carbonate reef trends would be expected to show analogous concentration gradients in the backreef area. End_of_Article - Last_Page 2039------------

A Comparative Study of Some Aspects of the Biology and Ecology ofSesarma CatenataOrt. andCyclograpsus PunctatusM. Edw., with Additional Observations onSesarma MeinertiDe Man

In the estuary of the Kowie River in the Eastern Cape Province there occur two amphibious grapsoid crabs, Sesarma catenata Ort. and Cyc/ograpsus punctatus M. Edw. They live together in many places, commonly inhabiting the same burrows in the muddy banks of the river. The present exploratory study of these two species has been undertaken to enhance our knowledge of their biology as well as our understanding of the relations between these two very similar animals which live in such close proximity one to another. THE HABITAT The Kowie River empties into the sea at Port Alfred, and is broad, winding and shallow. The tidal limit lies 13 miles from the mouth and over most of this length extensive, gently sloping mud banks are left exposed at low tide. The level of mean high tide is marked by a low salting cliff which is surmounted with vegetation. At Port Alfred itself the river runs between steep, stony, artificial dykes and on either side lie lagoons (Fig. 1). The lagoons on the East Bank (1, 2 and 3) are almost completely cut off from the river although an exchange of water does take place via seepage points in the dyke. The two western lagoons (4 and 5) are fully tidal. Large areas of the intertidal zone in the estuary are colonised by the tall, coarse marsh grass Spartina capensis Nees (S. stricta Roth.). This usually disappears about the level of High Water Neaps (HWN), to be replaced by a zone of typical salt marsh plants, dominated by Arthrocnemum, especially A. pillansii Moss, which has long stems, prostrate and woody at the base and terminating in erect green succulent tips. With the Arthrocnemum there may be min­ gled Spartina and Triglochin bulbosum L., particularly in low wet situations, and towards High Water Springs (HWS) Chenolea diffusa Thunb. A short distance below HWS Limonium scabrum (Thunb.) O.K. appears and spreads upwards, presently to give way to grasses, shrubs and trees. The zonation of plants on the banks of four of the five lagoons is very much the same as that along the river banks. The banks of Lagoon 4 (known locally as Little Beach) are sandy and devoid of vegetation. The two lagoons which lie furthest from the sea (3 and 5) contain masses of drifted algae, in particular the slender, branched brown alga Graci/aria verrucosa (Huds.) Papenf. The distribution of the two crabs in the area round Port Alfred is shown in Fig. 1. Beyond the town, where the river is not restrained by artificial dykes, the two species occur together

The origin and destruction of armored mud balls in a fresh-water lacustrine environment, Lake Superior

ABSTRACT The evolution and destruction of armored mud balls in a fresh-water lacustrine environment has been studied for the first time. The triaxial ellipsoid mud core formed in this environment results from erosion of mud banks along the shore. The majority of the particles composing the veneer of the armor is added to the core while it is in transit within the beach zone. After formation, storms throw the mud balls onto the beach. Depending upon the temperature prevailing at the time, the balls are soon destroyed, either by desiccation or by frost heaving. To date, no fossil mud balls have been found in the recent sediments of Lake Superior.

A Contribution to the Ecology of the Umlalazi Estuary

The UmIalazi river in Zululand is undergoing large scale changes due to deposition of mud from cultivated areas and a simultaneous rapid colonisation by mangroves chiefly Avicennia officinalis . The result is that open mud banks are being consolidated, shallows are changing into mangrove swamps and eventually into dry land. Much useful information can, be obtained from the study of aerial photographs and in the case of the Zululand coastal rivers we are fortunate in having two series of photographic surveys by the Trigonometrical survey. The photographs of the Umlalazi were made in 1937 and in 1960 and are reproduced in Fig. 1. The spread of mangroves and mud banks is obvious. In view of these changes it was felt that an ecological survey should be undertaken in order to record the present physical conditions and animal life in the estuary. As the mangrove invasion progresses the estuary will become narrower, shallows will disappear and tidal currents will become stronger. This should result in an increase in the fauna associated with mangrove swamps and a decrease in the shallow water fauna. Zoologica Africana 2 (1): 1-24

Distribution and Origin of Pennsylvanian Carbonate Mounds, Paradox Basin: ABSTRACT

Shelf carbonate mounds of Desmoinesian (Pennsylvanian) age were developed in cyclic repetition along the southwestern flank of the Paradox basin. Optimum carbonate deposition occurred in an elongate northwest-southeast belt, approximately 50 miles wide and over 100 miles long, which contains about 35 Pennsylvanian oil and gas fields. Porosity occurs in three types of carbonate reservoirs: algal plate mounds, foraminiferal mounds or bioherms, and leached oolite banks. Most of the production is from limestone, but dolomite also is important as a reservoir rock. Stratigraphic-facies mapping of the mound-bearing strata can be done on the basis of basin-wide, black, sapropelic shale marker beds, in conjunction with lithologic-petrographic analysis of rock types and associated faunal content. Shelf carbonate rocks occur in each main cycle of the Paradox Formation, grading basinward into evaporite and shoreward into sandy limestone and terrigenous clastic rocks. The origin, distribution, and cyclic repetition of the carbonate-mound belts are thought to be related to periodic eustatic changes in sea-level associated with late Paleozoic glacial cycles of the Southern Hemisphere. The mounds probably developed along shallow-water mud banks or platforms which built basinward during the early clastic phase of each cycle. Completeness and duration of a cycle were major factors in determining the size attained by the mound complex. End_of_Article - Last_Page 631------------

The Bordeaux Port Radar

At the end of 1963, to assist ships making use of the extensive facilities in the Gironde estuary, the port of Bordeaux installed surveillance radar covering the mouth of the Gironde. As it is still too early to assess its potentialities, this paper describes the technical arrangements and makes some general comments on the use of radar, suggested by the new installation.Ships approaching the Gironde estuary from the open sea follow the buoyed channel from the landfall buoy BXA, 18 kilometres west of Pointe de la Coubre. After picking up the pilot they enter the western or outer entrance passage, whose seaward termination lies 8 kilometres from the coast. This provides a dredged channel, 800 metres wide and 3500 metres long, running east–west. The depth of 12 metres at low water springs enables ships to cross the annular river bar separating the deep water on the seaward side from the mud banks at the mouth of the inner channel.

Aut Caesar, Aut Nihil: A Study of Dostoevsky's Moral Dialectic

In the first pages of The Brothers Karamazov the narrator recalls that he knew a young lady of the last romantic generation who, because of insuperable obstacles to union with her lover—all of which she had invented—one stormy night threw herself off a high precipice into a deep, rapid river. By this act she was able to satisfy her desire to be like Shakespeare's Ophelia; but, the narrator adds, had the precipice been less picturesque—a fiat mud bank, for instance—the suicide most probably would not have taken place. The romantic heroine, whose fate Dostoevsky brings up here only as an aside in his attempt to explain why Adelaida Ivanovna had married Fyodor Karamazov, recalls a character type which flourished on the pages of his works in the 1840's. Every reader of Dostoev-sky's early works will remember his bookish heroes, who prefer the beautiful improbabilities of romantic novels and the fantasies of their own minds to the reality they must live in. I am thinking of such obvious examples as the hero of White Nights, who for eight years has been intimately acquainted with characters from works of Hoffman, Scott, Goethe, and Mérimée, but who does not know a single real person in St. Petersburg. I am thinking, also, of the little hero from the story of the same name, who, in the seconds before he leaps on the unridable horse Tankred, sees in his mind's eye pictures of damsels, tournaments, pages, and all the paraphernalia of chivalry. As one who prefers fantasies to reality, Golyadkin of The Double is an obvious example; but even Makar Devushkin of Dostoevsky's first published work, Poor Folk, turns his back on the miserable conditions of his daily life and plays out the role of the generous benefactor to a young girl, even though the added economic burden drives him to drink and penury. There is hardly a work in the forties that does not have its dreamer: Netochka Nezvanova, huddled in a miserable corner looking across the street to the splendid house and dreaming of an improbable life, is a summary image of the hero of the forties.

The Japanese Gold Rush of 1859

One hundred years ago the patient efforts of Townsend Harris bore fruit and on July 4, 1859, Japan opened her doors to traders from the West. It was a small beginning, for Consul Harris' treaty allowed foreigners to live and trade at only three Japanese ports; two of which, Nagasaki and Hakodate, lacked the hinterland to make them much more than coaling or victualling stations. The third port was a small fishing village of twenty or thirty huts. It was built on a mud bank, backed by an odious swamp and commanded by surrounding hills. The Japanese called the place Yokohama.