R-3 Repository :: Browsing by Author "Warme, John E."

Browsing by Author "Warme, John E."

Now showing 1 - 13 of 13

A diagenetic study of the lower coralline limestone (oligocene), the Maltese Islands
(1980) Budai, Joyce M.; Wilson, James Lee; Baker, Donald R.; Warme, John E.
The Maltese Islands are located on a broad platform extending from northern Africa to Sicily which divides the Mediterranean Sea into an eastern and western basin. Strata exposed on the islands range from Upper Oligocene to Upper Miocene in age and are predominantly carbonates with one pelagic shale unit. This study focuses on the lowest formation, the Lower Coralline Limestone which is of Upper Oligocene (Chattian) age. The mid-Tertiary was a tectonically active time in the central Mediterranean. The western Mediterranean basin was forming during the Neogene and tectonic thrusting occurred to the west, north and east of the study area. Malta's location on a shallow, relatively stable platform in the center of a tectonically active Mediterranean places it in an interesting setting for diagenetic study. Unlike Recent carbonate sediments, the original mineralogic composition of the Lower Coralline Limestone was dominated by high magnesian and low magnesian calcite with only minor amounts of aragonite. Such a mineralogic assemblage would stabilize to low magnesian calcite rapidly and could conceivably affect early marine cementation and later episodes of fresh-water diagenesis. Fine-grained, fibrous marine cementation is present, but poorly preserved and limited to packstones and grainstones. Fresh-water, phreatic cements occurring in the Lower Coralline are more varied in crystal habit and abundant than the early marine cements. Three stages of meteoric cementation are recognized. An early period of syntaxial rim cements on echinoid fragments, accompanied or followed by grain compaction, forms the dominant cement type found in these rocks. These overgrowths display stratigraphically continuous luminescent zones like those reported in Mississippian limestones in New Mexico (Meyers, 1974) . The second phase of meteoric cementation produced fine- to medium-grained scal enohedra cement that clearly follows compaction and echinoid overgrowth development. These cements do not luminesce and constitute less than 20 percent of the fresh-water cements. The final stage of fresh-water cementation produced fine to medium grained, equant granular. void-filling spar. Diagenetic features examined in the Lower Coralline Limestone indicate at least two separate episodes of emergence and fresh-water cementation. Timing of emergent periods can be limited by extent of phreatic diagenesis within the lower units exposed on Malta. Stratigraphic relations of overlying formations that have been down-faulted into subsidence structures created by collapse of solution caverns within the Lower Coralline Limestone (Pedley, 1974) and limited erosional contacts in the lower part of the section provide possible times of fresh-water influence. In addition, proposed periods of subaerial exposure coincide closely with eustatic sea level drops described by Vail et al. (1978) .
A shoaling-upward carbonate sequence in the Dogger (Middle Jurassic) of the Central High Atlas of Morocco
(1976) Stanley, Richard Graham; Warme, John E.
A late stage of sedimentary infilling of the High Atlas Trough during Dogger (Middle Jurassic) time has been documented in a petrographic study of a 1,2 m-thick sequence of carbonate rocks exposed near Rich, Morocco. The sequence was studied in order to determine the events that led to the establishment of coral reefs in the center of a deeply subsided basin. Within this sequence, five lithologic units are distinguished and described in detail. The bulk of the sequence consists of rhythmically interbedded marls and fine-grained limestones that probably were deposited in quiet, relatively deep water. The hypothesis of progressive shallowing is supported by several lines of evidence, including upward increases in benthic vs. pelagic organisms, shelly vs soft-bodied benthic organisms, and algae and algal-coated particles. The sequence is capped by a 5-1 m-thick horizon of scleractinian coral reefs and coral-rich beds that probably formed in shallow, moderately agitated, well-illuminated marine environments. Evidence from local and regional stratigraphic relationships and insoluble residue analyses suggests that some large reef bodies within this horizon were established on local submarine topographic highs that formed as a result of tectonic activity during Dogger time.
Ecology and paleoecology of marine invertebrate communities in calcareous substrates, Northeast Quintana Roo, Mexico
(1973) Ekdale, Allan Anton; Warme, John E.
A survey of benthic communities in the vicinity of Isla Cancun and Isla Contoy, Territory of Quintana Roo, Mexico, demonstrates that invertebrate death assemblages (i.e., future fossil assemblages) in this region reflect the in-place accumulation of remains of living benthic communities through long periods of time. Samples were collected with a diver-operated suction dredge, and 290 molluscan species were identified and counted. Although nearly three-fourths of the species are known only as dead shells in the samples, almost all individuals occurring alive in any sample are represented by dead shells of their species in the same sample. Worn shells are uncommon, and a count of disarticulated bivalve valves revealed a nearly even left-right distribution. A series of twelve Q-mode cluster analyses, utilizing five different similarity coefficients and data based on both the presence or absence and the relative abundances of species, demonstrates that the same associations of samples tend to occur whether living animals only or dead remains only are considered. A Q-mode analysis based on the relative abundances of 180 species in the death assemblages of all 50 samples results in distinct clusters corresponding directly to each of the major environments sampled. An R-mode analysis of 66 common species in the death assemblages yields three distinct groups of organisms from environments of (a) restricted circulation, (b) open marine circulation and (c) swift currents. These results imply that large-scale transport of shell material and mixing of faunas from different environments are negligible in the areas sampled. Rankings of samples in terms of species diversity and total abundance indicate that most samples occupy roughly the same position in the lists whether only dead shells or only living organisms are considered. Associations computed between sample couplets with Chi-square tests and various similarity coefficients demonstrate that the death assemblages in each couplet are similar, whereas the living communities are not. Histograms of growth ring counts and size-frequency distributions of Chione cancellata in lagoon and strait samples resemble a mortality curve expected for a single generation of a living population of that species. The assemblages of dead shells in the sediments of this region represent "time-averaged communities" (Walker and Bambach, 1971), produced by the averaging of benthic communities during sedimentation as patchily distributed populations migrate across the bottom and leave a record of their mortality behind them in the sediment.
Fossil traces of the whitestone limestone and associated strata of the walnut formation, lower Cretaceous, south-central Texas
(1974) McCrevey, John Alfred; Warme, John E.
The abundant burrows and borings in the pelletoidal oolitic Whitestone Limestone and the Cretaceous marls and limestones which physically surround it were studied in an attempt to integrate the ichnology with the known stratigraphy and paleontology into a paleoenvironmental synthesis. Distorted and compacted burrows are common in the marls because these substrates remained soft during reworking by infauna. The lowest unit, the Bee Cave Marl, was burrowed and reburrowed by thalassinidean crustaceans in a subtidal environment. The highest unit, the Keys Valley Marl, has a distinctive fossil trace assemblage that includes Rhizocoral1ium, thalassinidean crustacean burrows, and unbranched burrows that gently spiral about a vertical axis. The latter burrows were probably produced by crabs in an intertidal environment. Small oyster reefs in both marls have bored shells and intraclasts. Thus borers lived in the environment and were able to function on the hardened substrates present in the subenvironments in and around oyster reefs. A limestone sequence deposited between the two marls underwent varying degrees of submarine lithification. Burrows of thalassinidean crustaceans in a limestone wackestone, the Cedar Park Limestone, have distinct walls. The coarse internal fill of the burrows contrasts with the wackestone matrix. The burrows are not distorted by soft sediment compaction, but are broken by early compaction faults and styolitization. Because no borings are present it is probable that the Cedar Park Limestone hardened internally while remaining soft at the sediment-water interface. Two limestone grainstones, the Whitestone Limestone and the Edwards Formation (the rudist bearing limestones beneath the Whitestone Limestone) have a distinctive trace assemblage that includes burrows and borings. Internally the laminations and cross bedding are intersected by soft sedit ment escape burrows. The borings, produced by annelids, sipunculids, bivalves, and sponges, occur only at the top of each grainstone. Because no evidence of subaerial exposure is preserved at either one of these bored horizons, they probably represent surfaces of submarine lithification. In this study, the morphology of the fossil traces in the marls provides a criterion for distinguishing between subtidal and intertidal strata. Also, the morphology and style of preservation of the traces provides evidence for the early lithification of the limestones.
Late paleozoic tectonic and sedimentologic history of the Penasco uplift, north-central New Mexico
(1980) Adams, Roy Donald; Anderson, John B.; Schwarzer, Rudy R.; Warme, John E.
The Paleozoic Peiiasco Uplift, located on the site of the present Nacimiento Mountains of north-central New Mexico, acted as a sediment source and modifier of regional sedimentation patterns from Middle Pennsylvanian to Early Permian time. The earliest history of the uplift is still poorly defined. Orogenic activity may have started as early as the Late Mississippian, or there may have been quiescence until after deposition of the Morrow-age Osha Canyon Formation and prior to deposition of the Atoka-age Sandia Formation. Coarse, arkosic siliciclastic sediments interbedded with fossilferious carbonates in the Madera Formation indicate that by early Desmoinesian time the Peiiasco Uplift had risen sufficiently to expose and erode Precambrian rocks. Paleotransport indicators in the arkosic sediments show transport away from the uplift. Throughout the remainder of the Pennsylvanian, the Peiiasco Uplift was a sediment source. The siliciclastic sediments derived from the Peiiasco Uplift formed a wedge that prograded out onto and interfingered with carbonate sediments of a shallow normal marine shelf. A change in paleotransport directions from northeasterly to southwesterly occurs on the east side of the Peiiasco Uplift and is due to the arrival of a flood of siliciclastic sediments derived from the Uncompahgre-San Luis Uplift to the northeast. This flood of sediments at or near the Permo-Pennsylvanian boundary, as dated by fauna in the uppermost Madera Formation, quickly breached the waning Penasco Uplift. Polycrystalline/total quartz ratios show that though breached, the Penasco Uplift continued as a sediment source during most, if not all, of Abo time. By the end of the Wolfcampian when Abo deposition ceased, the Penasco Uplift was no longer a sediment source and did not modify regional sedimentation patterns. Field relationships show that the two members of the Madera Formation, the lower gray limestone member of Atokan to Virgilian age, and the upper arkosic member of Desmoinesian to Virgilian age, are laterally equivalent and interfingering facies. The Abo to Madera formations are also, in part, laterally equivalent and interfingering. The Abo Formation ranges in age from Late Pennsylvanian to the end of the Wolfcampian in the Permian. The base of the Leonardian age Yeso Formation is gradational with the top of the Abo Formation.
Microfloral borers in recent Caribbean Scleractinian corals
(1976) Urish, Carol Lynn; Warme, John E.
Endolithic microflora were studied in recent scleractinian reef corals of Discovery Bay, Jamaica. Growing corals were collected at depths from sea level to 18 meters in the bay, forereef, and backreef. The inhabitants of coral genera Montastrea and Porites were selected for detailed study in each environment. The microborers, mainly endolithic green algae of the genus Ostreobium, were studied by means of SEM and thin sections. Thin-sections, the most successful technique, were made from horizontal and vertical sections of the coral skeletons. Filament counts were compiled for multiple transect lines in all samples. Montastrea skeletons contained many more filaments, possibly because their skeletons grow at slower rates than Porites. Algal filament variation within each species can be attributed to differences in coral growth rate, colony growth form, coral habitat, and depth. Although Ostreobium inhabits young corals, and grows and branches upward, only 47% of the specimens showed more filaments in the upper portions of the skeleton. Tiny filamentous tubes, within the skeletons were commonly still inhabited by microflora. The majority of corals studied contained green concentric algal bands within their skeletons. Counts substantiate that more algal penetrations, whether green with filaments or empty tubes, occur within these green bands. This fact suggests a correlation of greater numbers of algal filaments, green pigmented bands, and less dense skeletal material. Additional destructive and constructive evidence within the coral skeletons was present, and results from macroboring and encrusting organisms and incipient cementation.
Paleoenvironmental analysis of the Lower Middle Pennsylvanian deep-water sediments, Fort Worth Basin, Central Texas
(1976) Wagoner, John Charles van; Warme, John E.
The Fort Worth Basin, a marginal foreland basin of the Ouachita orogenic belt was a site of sedimentation during the Pennsylvanian. Lower Middle Pennsylvanian claystones, siltstones, and sandstones were studied where exposed south of Goldthwaite, Texas on the Colorado River. Physical sedimentary structures are present such as small scale ripple laminae, flute and groove casts, convolute and horizontal laminae, and syndepositional soft sediment slumps. Repeated sequences of graded beds are commonly associated with both parallel and convolute lamination. Trace fossils abound, including Zoophycos, Neonereites, Lophoctenium, Chrondrites, and one with a rosette shape. All other faunal evidence is lacking. Such physical and organic structures may be found in many different environments. Paleogeography of the Lower Middle Pennsylvanian including proximity of the rocks at Goldthwaite to deep-water rocks of similar age exposed nearby indicate the rocks studied were deposited in deep-water. Noticable lack of micro or macro fauna, absence of medium scale cross-bedding or ripples, the presence of turbidites, and abundant claystone both slumped and unslumped further substantiate deposition below storm wave base in deep-water. On the basis of distinctive rock types, paleocurrent directions, geometries of sandstone bodies, and assemblages of sedimentary structures three facies were recognized in the rocks studied along the Colorado River. They were arbitrarily designated Facies A, Facies B, and Facies C. Collectively the three facies are a portion of a submarine fan prograding approximately westward into the Fort Worth Basin, on the western edge of the Ouachita uplift. Facies A is a sandstone filled channel in the lowerinner to mid fan region. Facies B is interchannel claystones and siltstones, and Facies C represents either overbank deposition from a channel or a fine-grained channel fill. Based on the similarity of the tectonic history and relationship to the Ouachita geosyncline between the Fort Worth Basin and the Pennsylvanian Stanley and Atoka Basins it is concluded that submarine fan deposition active in the Fort Worth Basin is a viable model to apply to the now heavily deformed rocks of the Stanley, Johns Valley, and Lower Atoka Formations in the Ouachita Mountains.
Physical and biogenic sedimentary structures of a recent coastal lagoon
(1976) Biddle, Kevin T.; Warme, John E.
The physical and biogenic sedimentary structures of Mugu Lagoon, a shallow coastal lagoon in Southern California, were investigated in an effort to define suites of sedimentary structures and use them to divide the lagoon into sedimentary subenvironments. These data, coupled with grain size information, were used to prepare a depositional environment map of Mugu Lagoon. Seventy-three "can-cores" were taken along traverses in the lagoon. X-ray radiography and epoxy peel techniques were used to analyze the internal structures of the sediments. Twelve types of physical and six types of biogenic sedimentary structures were recognized, and the amount of bioturbation was estimated. On the basis of sedimentary structures the lagoonal system was divided into ten major subenvironments, which are: barrier beach, tidal delta, tidal channel, tidal creek, subtidal pond, barren zone or tidal flat, lower marsh, upper marsh, salt pan, and ancient sand ridge. Minor subenvironments , developed only locally within the lagoon, are: silt pellet dunes, tidal creek banks, and mussel beds. The subenvironments are characterized by different associations of physical sedimentary structures and the degree of biogenic reworking. A relationship between current strengths, sedimentation rates, and the amount of bioturbation exists. In subenvironments with rapid sedimentation rates and high energy regimes (e.g., barrier beach, tidal delta, tidal channel) physical structures predominate. In those areas with slow sedimentation rates and low energy regimes (e.g., subtidal ponds, upper marsh) biogenic structures are most common. Intermediate areas, such as the barren zone, are characterized by physical and biogenic structures in subequal amounts. The subenvironments defined by distinctive associations of sedimentary structures correspond extremely well with depositional environments recognized in Mugu Lagoon by other methods (Warme, 1966; 1971), showing that these depositional environments can be useful in interpreting similar modern analogs or ancient lagoonal systems.
Quaternary deep-sea lebensspuren and their relationship to depositional environments in the Caribbean Sea, the Gulf of Mexico, and the eastern and central North Pacific Ocean
(1975) McMillen, Kenneth James; Warme, John E.
Traces of marine benthos provide evidence of biological activity in the deep sea, even where few animals exist. Traces are not restricted to major ocean basins but some restriction to water depth does occur. The greatest distinction exists between different types of sediment. Burrows are of two types: 1) permanent burrows, and 2) temporary burrows. Permanent burrows tend to occur where sedimentation rates are low, as in pelagic sediments. Temporary burrows occur where sedimentation rates are rapid, as in turbidites. In the Cayman Trough, the relationship between burrowers and sedimentation has been studied in detail. The trough is a deep, linear basin isolated by ridges and islands from surrounding oceanic basins, with pelagic carbonate sedimentation occurring at the present time. Since the Late Pleistocene, sedimentation has consisted of 1) distal turbidites, succeeded by 2) sediments deposited by currents generated by a turnover of bottom water accompanying the post-Pleistocene rise in sea level, and followed by 3) pelagic sedimentation. The traces respond to this succession of sediments. Temporary burrows occur in turbidites and bottom-current sediments, and only permanent burrows occur in pelagic sediments. Permanent burrows are mainly used for protection by filter-feeding organisms, whereas temporary burrows that are actively filled by the organism are produced by sediment-ingesting organisms. These feeding patterns are the result of the way food is distributed in the sediment. Temporary burrows that are actively filled occur where food is buried in the sediment, as it is in turbidity-current sediments, bottom-current sediments, and hemipelagic sediments. Permanent burrows occur where food supply is less so it accumulates near the surface, or is intercepted before it reaches the sea floor, which is the case in pelagic sediments.
Recent Foraminiferal associations from northeastern Quintana Roo, Mexico
(1974) Ekdale, Susan Faust; Warme, John E.
A faunal survey of the foraminifera distributed in shallow carbonate areas off the Northeast Quintana Roo (Mexico) coast is undertaken in order to determine the species present and the environments in which they occur. A total of 222 species of foraminifera is found in 3 samples located off the islands of Isla Cancun and Isla Contoy. Presence-absence Q-mode cluster analysis outlines seven distinct foraminiferal environments: proximal near back-reef, distal near back-reef, submerged dune ridge, tidal channel, strait, open lagoon, and restricted lagoon. Foraminiferal diversities and densities correlate strongly with the clustered environments. Foraminiferal associations yielded from presence-absence R-mode cluster analysis reaffirms the basic environments outlined by the Q-mode analysis. A comparison of the foraminiferal and mollusc an faunas from the same sample stations reveals comparable environmentally correlated distributions.
Sedimentary facies and trace fossils in the Eocene Delmar Formation and Torrey Sandstone, California
(1975) Boyer, Jannette Elaine; Warme, John E.
The Delmar Formation and Torrey Sandstone were studied in seacliff outcrops at Solana Beach, about 15 km north of San Diego. There, they represent lagoonal and barrier bar or shoal deposits, respectively. Five subfacies were recognized in these outcrops, utilizing observations on sediments, physical sedimentary structures, body fossils and trace fossils. The Delmar exhibits three subfacies that formed as oyster reefs, tidal flats, and sublittoral tidal channels and ponds. The Torrey contains two subfacies, representing subaqueous dunes and tidal channels on a tidal delta or interior side of a barrier bar or s.hoal, and large, temporary channels generated by drainage of the lagoon after periods of high run-off or storms. Trace fossils contribute significantly to the description and interpretation of these subfacies. Their density and diversity indicate brackish to marine conditions. The abundant lebensspuren Ophiomorpha nodosa and Gyrolithes indicate deposition in littoral to inner sublittoral zones; Gyrolithes is especially common in brackish environments of the Delmar lagoon. Sandy, high-energy facies of the Torrey Sandstone are characterized by large, verticallyoriented dwelling burrows and by vertical locomotion traces generated by infauna migrating up and down in response to sedimentation and erosion. Muddy, more protected environments of the Delmar Formation exhibit lese robust, horizontally-oriented dwelling burrows and an abundance of feeding burrows constructed by animals mining the organic-rich sediment for food. Sedimentation and physical reworking were very active in Torrey environments, so trace fossils there distort but do not obliterate physical sedimentary structures and bedding characteristics. In contrast, much of the Delmar has been heavily bioturbated, indicating predominance of biological reworking over physical processes.
Sedimentation in the north San Clemente basin, California continental borderland
(1979) Pratt, David E.; Warme, John E.; Casey, Richard E.; Clark, Howard C.
Three broad sedimentary environments within the north San Clemente Basin have been defined. The south slope of San Clemente Island and the northernmost part of the San Clemente Basin receive predominantly siliciclastic sediments shed from San Clemente Island. Clastic sediments deposited in San Clemente Canyon are sorted and transported by the action of tidally generated currents. Currents measured in the canyon show upcanyon and downcanyon reversals of flow nearly every 12 hours, and currents reached velocities of 18 cm/second during periods of peak flow. The currents have winnowed silt and clay from sediments at the head of the canyon, leaving a sandy lag deposit. Pine-grained sediment is transported into the basin and slowly deppsited as the currents lose velocity. Three piston cores from the northern part of the basin penetrated the Holocene-Plelstocene boundary. Slightly more than a meter of Holocene sediment was measured in each core, as determined by mlcropaleontologic methods. The central part of the north San Clemente Basin is dominated by pelagic sedimentation. Basin physiography effectively blocks transport of clastic sediments from San Clemente Island and mainland California to the area. Hemipelagic sediments and distal turbidites are transported through the Navy Fan of the south San Clemente Basin and into the southern part of the study area. The observed distal turbidites may be a result of Early Holocene sea-level regressions. Sediments within the north San Clemente Basin are in a reducing environment, as indicated by their color and the presence of authigenic sulfides. Micropaleontologic data from this study indicate that kummerform Globlgerina pachyderma tests are a result of displacement into unfavorable environments.
Sedimentology of Laguna Potosi and environs, State of Guerrero, Mexico
(1976) Sanchez-Barreda, Luis; Warme, John E.
Laguna Potosi belongs to a series of 32 coastal lagoons along the south and the southwest coast of Mexico. The region is characterized by a narrow coastal plain interrupted by isolated granite emplacements and bordered by the Pacific Ocean on the south and the Sierra Madre del Sur on the landward side. Laguna Potosi is located in the equatorial to subequatorial climatic zone with a rainy summer and a dry hot winter. The lagoon is characterized by mangrove and marsh vegetation, salt pans, interlagoonal channels, a singular headland, a steady inflow of fresh water, and a seasonal inlet. A total of 56 samples were selected for grain size and statistical analysis. Modes and medians of the samples were determined by conventional techniques while standard deviation, skewness, and kurtosis were calculated useing the method of central moments about the mean. Because of the complexity of the data, the multivariate technique of cluster analysis was utilized. From combined statistical analyses and diagramatic schemes, it was concluded that sand; size sediments in Laguna Potosi are derived from the bay-beach and introduced into the lagoon by the seasonal tidally-induced currents. Silts and clays deposited in the lagoon are derived from the surrounding farmed areas and reach the inflow channel by means of surface runoff. R-mode cluster analysis of the polymodal sediments indicates that the coarse and medium sands in the lagoon belong to the same statistical population as those sands occurring along the present shorelines. This similarity suggests that ancient shorelines and/or beach facies can be located within coastal lagoons.

Browsing by Author "Warme, John E."

Results Per Page

Sort Options