Midcontinental United States Research Articles

Situational and Dispositional Determinants of Cognitive and Affective Reactions to the New Madrid Earthquake Prediction

A New Mexico climatologist, Iben Browning, forecast an even chance that a major earthquake would strike the New Madrid fault on or around December 3, 1990. The extended media coverage associated with this “projection “ may have generated the most acute public awareness of earthquake hazards in the mid-continental United States in recent memory. In order to investigate what effect situational and dispositional factors had on cognitive and affective reactions to Browning's “projection, “ 428 college students residing in the area of Southeast Missouri predicted to be affected by an earthquake on the New Madrid fault were administered an extensive questionnaire. The questionnaire determined how situational factors (sociodemographic characteristics, prior earthquake experience, and impact attributed by the respondents to exposure to media sources of information) and dispositional factors (personality characteristics) were related to their reactions towards Browning's “projection. “ The results indicated ttat the cognitive and affective reactions to an earthquake prediction assessed in this study can be partially predicted from a combination of situational, but not dispositional, factors.

Stratigraphy and Radiocarbon Chronology of Modoc Rock Shelter, Illinois

Excavations at Modoc Rock Shelter, Illinois (11R5), between 1952 and 1956 documented the antiquity and cultural sequence of the Archaic period in the midcontinental United States. Some researchers questioned the site's stratigraphic integrity because of apparent inconsistencies between the radiocarbon assays and associated artifacts. Excavations in 1980, 1984, and 1987 documented stratigraphic sequences and produced assays of over 40 additional radiocarbon samples from controlled stratigraphic contexts. This report describes the stratigraphic sequences at Modoc Rock Shelter and presents critical evaluations of the radiocarbon assays. This information is used to summarize the depositional and occupational history of the site. Two related stratigraphic sequences are present, one in the Main Shelter and a separate, physically uncorrelated sequence in the West Shelter. Each sequence includes occupations dating to the Early, Middle, and Late Archaic periods, with age ranges between 9000 and 4000 B.P. Questions about the site's stratigraphic integrity, artifact sequences, and analytical procedures are resolved.

Paleoceanographic and tectonic implications of a regionally extensive Early Mississippian hiatus in the Ouachita system, southern mid-continental United States

A regionally extensive Early Mississippian hiatus is recognized at the transition from preflysch to flysch rocks in the Ouachita system of the southern mid-continental United States. It is recognized only in sections where detailed biostratigraphic control exists, and it is coeval with a regional unconformity in the Ouachita foreland throughout parts of Texas, New Mexico, and Oklahoma. Widespread Early Mississippian erosion and nondeposition is attributed to a reconfiguration in basin geometry caused by the onset of Ouachita orogenic activity. Crustal flexure resulting from the impending collision would have initiated erosional processes throughout the foreland, while simultaneously altering bottom-current pathways in the basin and allowing for a prolonged period of sedimentary bypass. In the Late Mississippian, increased constriction may have eventually cut off transequatorial bottom-water circulation, allowing deposition to resume on the shelf and in the basin. An important tectonic implication of this study is that Ouachita deformation started in the Late Devonian to earliest Mississippian, at least 10 m.y. before the onset of flysch deposition.

Seed Dormancy in the Prairie Forb Echinacea angustifolia Var. Angustifolia (Asteraceae): Afterripening Pattern During Cold Stratification

Cold stratification was required to break dormancy in seeds of Echinacea angustifolia var. angustifolia, a widely distributed taxon of prairies and barrens in the midcontinental United States. The temperature requirements for germination of E. angustifolia seeds coming out of dormancy differ from those reported for 15 other species of Asteraceae, which first began to germinate at high (30/15, 35/20) or at medium (20/10 C) temperatures. As seeds of E. angustifolia began to afterripen, they germinated over a range of thermoperiods including 15/6, 20/10, 25/15, and 30/15 C. After 8 wk of stratification, seeds germinated to 63%-91% at 15/6, 20/10, and 25/15 C. Thus, even when seeds are not fully afterripened, they can germinate to high percentages at low spring temperatures, whereas those of other spring-germinating composites must be nondormant to germinate well at low temperatures.

Offset VSP: A tool for development drilling

A large portion of today’s drilling activity in the Midcontinent United States is aimed at finding new oil and gas in mature producing areas, i.e., exploitation. Exploitation within these mature areas requires the utmost accuracy in picking well locations because smaller reserves are being sought than in the initial exploration cycle.

Distribution of agrochemicals in the lower Mississippi River and its tributaries

The Mississippi River and its tributaries drain extensive agricultural regions of the Mid-Continental United States. Millions of pounds of herbicides are applied annually in these areas to improve crop yields. Many of these compounds are transported into the river from point and nonpoint sources, and eventually are discharged into the Gulf of Mexico. Studies being conducted by the U.S. Geological Survey along the lower Mississippi River and its major tributaries, representing a 2000 km river reach, have confirmed that several triazine and acetanilide herbicides and their degradation products are ubiquitous in this riverine system. These compounds include atrazine and its degradation products desethyl and desisopropylatrazine, cyanazine, simazine, metolachlor, and alachlor and its degradation products 2-chloro-2′,6′-diethylacetanilide, 2-hydroxy-2′,6′-diethylacetanilide and 2,6-diethylaniline. Loads of these compounds were determined at 16 different sampling stations. Stream-load calculations provided information concerning (a) conservative or nonconservative behavior of herbicides; (b) point sources or nonpoint sources; (c) validation of sampling techniques; and (d) transport past each sampling station.

Stone Age Spear and Arrow Points of the Midcontinental and Eastern United States

Stone Age Spear and Arrow Points of the Midcontinental and Eastern United States

Mushrooms and Other Fungi of the Midcontinental United States, by D. M. Huffman, L. H. Tiffany, and G. Knaphus [Review

Mushrooms and Other Fungi of the Midcontinental United States, by D. M. Huffman, L. H. Tiffany, and G. Knaphus [Review

Nd Isotopes and the Origin of Grenville-Age Rocks in Texas: Implications for Proterozoic Evolution of the United States Mid-Continent Region

Nd isotopic data were obtained for Precambrian Grenville-belt rocks in Texas. The samples represent most components of the crust of the Llano, Van Horn, and Franklin Mountains exposed terranes. Almost all Precambrian igneous, metamorphic, and sedimentary rocks from the three regions document addition to North America of mantle-derived crustal materials in the 1.6-1.0 Ga interval. The exception is a quartzite from the westernmost (Franklin Mountains) exposure, which was derived from ~1.8 Ga crust of the southwestern United States. The initial values of all rocks except the quartzite lie in the +1 to +6 range for igneous/metamorphic ages of 1.37 to 1.06 Ga. These results can be interpreted in two ways: (1) as documenting 0-20% additions of older crustal material to mantle-derived products 1.4-1.0 Ga ago; or (2) as documenting derivation of the Grenville exposures by recycling of older crustal protoliths separated from the mantle 1.6-1.3 Ga ago. The Nd data in isolation do not resolve these two interpretations. The model mantle separation ages () of the rocks are very similar to published values of granulites in Mexico and Virginia: all these regions of the United States and Mexico show a strong peak of around 1.4 Ga ago. If the ages represent older crustal protoliths, then they would have formed coevally with the 1.5-1.3 Ga Granite-Rhyolite Terranes of the continental interior USA. This would imply that the Granite-Rhyolite Terranes were formed during orogenic/accretionary processes in the adjoining Grenville Belt, and are not anorogenic in association, as conventionally assumed.

Pressure-Volume-Temperature Correlations For Western Canadian Gases And Oils

Abstract Empirical correlations for the prediction of reservoir fluid properties have played a significant role in the design of petroleum production facilities and in reservoir engineering studies. Katz(1), In. 1942, developed a correlation from Mid-Continent crudes data to predict formation volume factors. Since then many researchers and investigators have developed either new or improved correlations of this nature. The fundamental concept behind most of the empirical correlations is to estimate fluid properties such as solution gas-oil ratio, formation volume factor, and bubble point pressure as a function of field-measured quantities. These quantities include crude oil API gravity, gas specific gravity, flash gas-oil ratio, reservoir pressure and temperature. Recently the accuracy of several well-known correlations, such as Standing, Lasater, Vazquez(2–4) and others were investigated for 300 different fluid sample from western Canadian oil and gas reservoirs. The results indicated that in many cases the correlations were not accurate. This result was expected as no correlations have ever been developed using fluid properties of western Canadian crudes. The objective of this study is to develop new sets of correlations to improve the accuracy of estimating physical properties and phase behaviour for western Canadian crudes based on over 10 different samples from this region. Correlations were developed for different geological formations where sufficient data was available to warrant the statistical approach. The new correlations will benefit practicing engineers in their day-to-day duties. Introduction The evaluation of the fluid properties plays a significant role in the design of surface operation facilities and reservoir engineering studies. In many occasions when the bubble point pressure, solution gas-oil ratio and formation volume factor are not available for various reasons, it is desirable to be able to estimate these properties from measured parameters in the field such as pressure, temperature, gas specific gravity, oil gravity and flash gasoil ratio. Development of correlations for the fluid properties based on readily available measured parameters in the field has been the subject of investigation for over forty-five years. Katz(1) in 1952 developed a correlation for formation volume factor based on 117 oil samples from Mid-Continent crudes. Standing(2) developed correlations for bubble-point pressure, formation volume factor as an empirical function of gas-oil ratio, specific gas gravity.oil API gravity, and temperature. In 1957, Lasater(3) developed correlations for bubble-point pressure based on 158 experimentally-measured bubble-points pressure obtained from Canada, the western and mid-continental United States and South America.He expressed the bubble-point pressure in terms of field measured separator gas-oil ratio, tank oil gravity, total gas gravity nd reservoir temperature. Knopp and Ramsey(5) in 1959 correlated thermally-reduced oil formation volume factors with solution gas-oil ratio. This correlation was made from the differential liberation data of 159 analyses of saturated eastern Venezuelan crudes. Glasco(6) developed correlation for North Sea oil to estimate bubble-point pressure, formation volume factor from field-measured separation gas-oil ratio, gas gravity, stock-tank oil gravity and reservoir temperature. In 1977, Vasquez and Beggs(4) presented correlations for solution gas-oil ratio, formation volume factor, and viscosity.

: Stone Age Spear and Arrow Points of the Midcontinental and Eastern United States: A Modern Survey and Reference . Noel D. Justice.

: Stone Age Spear and Arrow Points of the Midcontinental and Eastern United States: A Modern Survey and Reference . Noel D. Justice.

Anorogenic magmatism and the Grenvillian Orogeny

The Grenvillian Orogeny was preceded by extensive anorogenic volcanism and plutonism in the period 1500–1300 Ma in the form of rhyolites, epizonal granites, anorthosites, gabbros, alkaline complexes, and basic dykes. An analogue for the mid-Proterozoic anorogenic complexes is provided by the 2000 km by 200 km belt of anorogenic complexes in the Hoggar, Niger, and Nigeria, which contain anorthosites, gabbros, and peralkaline granites and were generated in a Cambrian to Jurassic rift that farther south led to the formation of the South Atlantic. An analogue for the 1 × 106 km2 area of 1500–1350 Ma rhyolites (and associated epizonal granites) that underlie the mid-continental United States is provided by the 1.7 × 106 km2 area of Jurassic Tobifera rhyolites in Argentina, which were extruded on the stretched continental margin of South America immediately preceding the opening of the South Atlantic. The mid-Proterozoic complexes were intruded close to the continental margin of the Grenvillian ocean and were commonly superimposed by the craton-directed thrusts that characterized the final stages of the Grenvillian Orogeny. The bulk of the Keweenawan rift and associated anorogenic magmatism formed about 1100 Ma at the same time as the Ottawan Orogeny in Ontario, which probably resulted from the collision of the island arc of the Central Metasedimentary Belt attached to the continental block in the east with the continental block to the west. The most appropriate modern equivalent would be the Rhine Graben, which formed at the same time as the main Alpine compression.

Upper Ordovician conodonts, brachiopods, and chronostratigraphy of the Whittaker Formation, southwestern District of Mackenzie, N.W.T., Canada

Ten samples from a 160 m section through the lower Whittaker Formation yielded Red River Province conodonts as well as a shelly macrofossil assemblage representing the "Arctic Ordovician fauna." Both the microfossils and macrofossils have strong affinities with taxa represented in strata of Cincinnatian age in the western Midcontinent Province of North America.Conodont-based graphic correlation of section W-1 with a Composite Standard Section developed for midcontinental United States indicates that the lower Whittaker Formation on the east flank of the Redstone Arch represents nearly the entire Cincinnatian Series. Trilobites of the Ceraurus mackenziensis Zone occur in strata correlative with the upper Edenian and those of the Whittakerites planatus Zone first appear at or just below the projected base of the Maysvillian Stage. The age of the Ceraurinella necra Zone is still uncertain but is likely to be early Edenian.Thaerodonta recedens (Sardeson) and other elements of the Bighornia – Thaerodonta fauna also debut in uppermost Edenian or lowermost Maysvillian strata. The morphology of Sowerbyella redstonensis n.sp. and Thaerodonta recedens from the lower Whittaker Formation indicates that the common ancestor of early Thaerodonta species may have arisen during latest Edenian time. The first appearance of Thaerodonta may constitute a useful biostratigraphic datum throughout the Red River Province. The strongly Thaerodonta-like species, Sowerbyella redstonensis n.sp., is described from silicified material of mid-Edenian age.

Statistical Evaluation of PVT Correlations Solution Gas-Oil Ratio

Abstract The predictive accuracy of three commonly used correlations for the solution gas-oil ratio is tested against new data from 385 PVT tests. To perform an unbiased evaluation, this study is made using strictly PVT data which are not used in the development of any of the chosen correlations. The performance of each correlation is compared over selected ranges of oil API gravity. The comparison indicates the relative strengths and weaknesses of each correlation and should aid in the selection of a satisfactory correlation for certain conditions. The best over-all performance is obtained using the Vazquez-Beggs correlation, based on consistently low values of absolute per cent error and standard deviation. Introduction The prediction of physical fluid properties is one of the main concerns in the handling of the different stages of oilfield operations such as in the determination of pressure losses occurring in multiphase flow situation, the design of surface operation facilities, and the design of reservoir performance operations. Some of these properties are solution gas-oil ratio, oil FVF, and oil viscosity. The purposes of this study are to (1) ascertain the accuracy of the existing solution gas-oil ratio prediction correlations, and (2) define the areas of application of each correlation. The correlations included in this study, as described below aTe the Standing(l), Lasater(2), and Vazquez-Beggs(3) correlations. Standing Correlation In 1947, Standing presented the results of a laboratory study of the PVT behaviour of 22 different crude oil natural gas mixtures from California oil fields. His correlation, which was derived from 105 experimental data points, can be expressed as: Equation (Available In Full Paper) Lasater Correlation Lasater in 1958 presented a correlation of bubble point pressure derived from data on black oil systems produced in Canada, western and mid-continental United States and South America. The correlation is based on 158 experimental measured bubble point pressures of 137 independent systems and is expressed as: Equation (Available In Full Paper) The effective molecular weight (EMWGT) is related to API gravity as shown in Figure 1. Lasater found a satisfactory correlation of bubble point pressure factor (BPPF) with gas mole fraction (GMF) as shown in Figure 2. Equation (Available In Full Paper) Vazquez-Beggs Correlation In 1976, Vazquez and Beggs developed an empirical correlation for gas evolution using data from more than 600 PVT analyses from fields all over the world. The correlation is derived from 5008 experimental data points, and is defined as: Equation (Available In Full Paper) Data Acquisition and Preparation To perform an unbiased evaluation, this study is made using strictly PVT data which are not used in the development of any of the previous chosen correlations. The data bank used in this study (385 points) are obtained from four different unpublished sources. In these sources, the flash separation data are used in conjunction with the values of the flash and differential process to calculate the solution gas-oil ratio.

Revision, distribution, and extinction of the Middle and early Late Devonian archaeogastropod genera Floyda and Turbonopsis

Large palaeotrochid gastropods of the genera Floyda Webster (1905a) and Turbonopsis Grabau and Shimer (1909) occur in the late Frasnian Lime Creek Formation of Iowa. Floyda concentrica was designated as the type species of Floyda by earlier workers (Webster, 1905a; Knight, 1941), but is a junior synonym of F. gigantea (Hall and Whitfield, 1873). Three of five species and subspecies of Floyda described from the Lime Creek (Floyda concentrica, F. concentrica multisinuata, and F. gigantea depressa) are considered synonyms of the type species F. gigantea; the fifth species, F. gigantea hackberryensis, is here reassigned to the closely related genus Turbonopsis. Both F. gigantea and T. hackberryensis are redescribed using the original types and additional hypotype material from the collections of Charles Belanski.Floyda, first known from late Givetian rocks of the Rhenish Slate Mountains in Germany, is widespread in the United States Midcontinent and western North America by early Late Devonian time. Turbonopsis was endemic to the Appohimchi Subregion of the Eastern Americas Realm prior to the Taghanic Onlap, and appears to have remained so until late Frasnian time when it migrated to western North America.Eustatic sea-level highstands during the Middle and Late Devonian are thought to have breached barriers to migration, allowing both Floyda and Turbonopsis to disperse by prevailing oceanic currents from the United States Midcontinent into western North America during the late Frasnian. The expected oceanic current patterns of the Middle and Late Devonian paleogeographic reconstructions of Heckel and Witzke (1979, figs. 3, 5) adequately account for the known distribution and dispersal of Devonian palaeotrochid gastropods.The Palaeotrochidae underwent extinction prior to the latest Frasnian. Floyda, Turbonopsis, and Westerna became extinct during the onset of the last eustatic deepening event prior to the close of the Frasnian. The extinction of the palaeotrochid gastropods as well as other invertebrate groups may have been the result of restriction or near elimination of shallow warm-water, well-oxygenated shelf habitats by the onlap of cold anoxic bottom waters prior to latest Frasnian time.

The relationship between the iridium anomaly and palynological floral events at three Cretaceous-Tertiary boundary localities in western Canada

Profiles illustrating the abundance of iridium and the changes in the relative abundances of major groups within the palynoflora are given for three localities from western Canada. The peak abundance of iridium ranges from 1.35 to 5.60 ppb and corresponds to the base of a coal and to a floral-extinction event at the three localities. Immediately above the iridium-peak anomaly, angiosperm pollen is conspicuous in the assemblage, in contrast to the fern-spore spike described for sections in the mid-continental United States and at the Morgan Creek locality in south-central Saskatchewan.

Possible Late Middle Ordovician Organic Carbon Isotope Excursion: Evidence from Ordovician Oils and Hydrocarbon Source Rocks, Mid-Continent and East-Central United States

Oils generated by Middle Ordovician rocks are found throughout the Mid-Continent and east-central regions of the United States. Gas chromatographic characteristics of these oils include a relatively high abundance of n-alkanes with carbon numbers less than 20, a strong predominance of odd-numbered n-alkanes between C10 and C20, and relatively small amounts of branched and cyclic alkanes. Saturated and aromatic hydrocarbon fractions of 43 Ordovician oils from the Anadarko, Ardmore, Forest City, Illinois, Michigan, Salina-Sedgwick, and Williston basins and the Iowa shelf demonstrate a wide range in carbon isotope composition (^dgr13Csat = -24.9 ^pmil to -33.9 ^pmil, (^dgr13Carom = -24.3 ^pmil to -33.7 ^pmil). Saturated and aromatic hydrocarbons extracted from late Middle Ordovician shales (17 core samples) show ranges in ^dgr13C similar to that of the oils. The wide ranges in ^dgr13C for oils and rock extracts reflect a major, positive excursion(s) (6-9 per ^pmil) in organic matter ^dgr13C in late Middle Ordovician rocks. This excursion has at least a regional significance in that it can be documented in sections 480 mi (770 km) apart in south-central Kansas and eastern Iowa. The distance may be as much as 930 mi (1,500 km) if the carbon isotope variations observed in Michigan basin Ordovician oils and in organic matter from late Middle Ordovician rocks in southwestern Ontario are related to the same carbon isotope excursion. Organic-matter ^dgr13C in core samples from south-central Kansas and eastern Iowa is not directly related to variations in quantity or quality of organic matter, or maceral compositi n. The positive excursion in organic matter ^dgr13C is a possible result of increased organic matter productivity and/or preservation. The parallel shifts in organic and carbonate ^dgr13C in core samples from 1 E. M. Greene well, Washington County, Iowa, imply changes in the isotope composition of the ocean-atmosphere carbon reservoir. Differences in the magnitude of the carbon isotope shifts between organic matter (8.8 ^pmil) and carbonate (4.2 ^pmil) in this core suggest a decrease, either locally or regionally, in available dissolved CO2, possibly a result of high organic-matter productivity and/or limited circulation in the late Middle Ordovician seas.

Tectonic significance of precambrian apatite fission-track ages from the midcontinent United States

Apparent apatite fission-track ages from drill core penetrating basement on the flank of the Transcontinental Arch in northwestern Iowa range from 934 ± 86 to 641 ± 90 Ma. These ages, the oldest reported in North America, record at least two thermal events. The 934 Ma age, which is synchronous with K-Ar ages in the Grenville Province and many K-Ar whole-rock and Rb-Sr isochron ages from the Lake Superior region, may document basement cooling caused by regional uplift and erosion of the crust. The remaining fission-track ages are products of a more recent thermal event, relative to the age of the samples, which raised temperatures into the zone of partial annealing. Heating may have occurred between the Middle Ordovician and Middle Cretaceous by burial of the basement with additional sediment. It is estimated that burial raised temperatures in the part of the basement sampled by the core to between 50 and 75°C. These temperature estimates imply paleogeothermal gradients of about 20°C/km, approximately two and one-half times present-day values, and burial of the basement by an additional 2–3 km of sediment.

The timing of ore formation in Southeast Missouri; Rb-Sr glauconite dating at the Magmont Mine, Viburnum Trend

Seven Bonneterre and Davis Formation glauconite samples from the Magmont mine area, Viburnum Trend, southeast Missouri, yield a 359 + or - 22-m.y. Rb-Sr isochron with an initial 87 Sr/ 86 Sr ratio of 0.7234 + or - 0.0273 (2 sigma). Gangue calcite from the ore zone has an 87 Sr/ 86 Sr ratio of approximately 0.7112. The isochron age for the Magmont glauconite samples is about 30 percent younger than the age of their Cambrian host rocks.The Rb/Sr ratios for Magmont glauconite samples are typical of many early Paleozoic glauconites but distinctly lower than ratios for glauconites from unmineralized localities in basinal Bonneterre facies, some distance from the Vibrunum Trend.Because the Rb-Sr data from Magmont glauconite samples define an isochron, it appears that the glauconites behaved as a cogenetic suite which was isotopically homogenized 359 m.y. ago. It is very unlikely that episodic or incomplete loss or exchange of radiogenic strontium, or the addition of rubidium, would result in the formation of an isochron. Addition of common strontium (mixing) will lower and produce a greater spread in Rb/Sr ratios but will not significantly change the calculated Rb-Sr isochron age for the glauconites. Because the total thickness of stratigraphic cover in the southeast Missouri region has never exceeded a kilometer, it is unlikely that the anomalously young glauconite isochron age resulted from heating associated with deep burial. Mississippi Valley-type ore fluids offer a hot, chemically reactive medium which could promote isotopic homogenization in glauconites. Therefore, the 359-m.y. age probably reflects a real geologic event, most likely the time of ore formation in southeast Missouri.A review of other attempts at dating early Paleozoic glauconites from the midcontinental United States indicates that all Rb-Sr and K-Ar glauconite ages are 10 to greater than 30 percent younger than their known stratigraphic ages. These glauconites are from Paleozoic formations on the stable craton, and again, resetting due to burial metamorphism is unlikely. Because there was no immediately obvious explanation for the discordant young ages, early Paleozoic glauconites were simply considered to be unsuitable geochronometers. It is suggested that the anomalously young radiometric ages for early Paleozoic glauconites record disturbances in the Rb-Sr and K-Ar isotopic systems, the result of Mississippi Valley-type fluid migration in the midcontinent region.

Sulfur Isotopes Related to Sedimentation Conditions for Metalliferous Black Shales of Pennsylvanian Age: ABSTRACT

Sulfur isotope compositions were determined for pyrite and sphalerite grains isolated from 8 metalliferous Missourian, Desmoinesian, and Atokan black shales from Missouri, Illinois, Kansas, and Indiana. The younger Missourian shales from the Forest City and Illinois basins contain consistently light sulfur as expected for euxinic conditions, but sulfides from the older shales show heavier and more erratic sulfur values. These isotope patterns suggest that younger shales accumulated slowly offshore, although older shales may have been deposited more quickly in shallower water. Isotope values, which also correlate with heavy metal patterns (e.g., higher molybdenum values for the easternmost older shales), may therefore reflect gradually deepening conditions for the epicontinental Pennsylvanian seas of the United States Mid-Continent. End_of_Article - Last_Page 246------------