Physical Sciences and Mathematics Commons^™

Speleothems As Proxy For The Carbon Isotope Composition Of Atmospheric Co2, M. Baskaran, R. V. Krishnamurthy

Environmental Science and Geology Faculty Research Publications

We have measured the stable isotope ratios of carbon in a suite of recent cave deposits (<200 >years) from the San Saba County, Texas, USA. The methodology for dating these deposits using excess ²¹⁰Pb was recently established [Baskaran and Iliffe, 1993]. The carbon isotope ratios of these samples, spanning the time period ∼1800–1990 AD, reflect the carbon isotope ratio of atmospheric CO₂ for the same period. The pathways by which the δ¹³C of atmospheric CO₂ is imprinted on these speleothems can be explained using a model developed by Cerling (1984). The results suggest that the …

Geology Newsletter- 1993, Department Of Geology

Geological and Environmental Sciences News

Vol.1, No. 18

• Faculty News
• Awards and Scholarships
• Service Staff News
• Hydrogeologic Atlas Available
• Alumni/ Friends/ Former Faculty Notes
• Geology Development and Scholarship Donations

Field Test Of A Calcite Dissolution Rate Law: Fort’S Funnel Cave, Mammoth Cave National Park, J. Scott Slunder

Masters Theses & Specialist Projects

The laboratory-derived calcite dissolution rate law of Plummer et al. (1978) is the most widely used and mechanistically detailed expression currently available for predicting dissolution rates as a function of water chemistry. Such rate expressions are of great use in understanding timescales associated with limestone karst development. Little work has gone into the field testing of the rate law under natural conditions.

This work compared measured dissolution rates measured by a crystal weight loss experiment in Buffalo Creek within Fort’s Funnel Cave, which lies within a pristine, forested catchment of Mammoth Cave National Park. Continuous water chemistry sampling over the …

Atmospheric Depositional Fluxes Of 7Be And 210Pb At Galveston And College Station, Texas, M. Baskaran, Charles H. Coleman, Peter H. Santschi

Environmental Science and Geology Faculty Research Publications

The bulk depositional fluxes of ²¹⁰Pb and ⁷Be were measured at a coastal (Galveston) and an inland (College Station) station for about 3 years, between 1989 and 1991. The annual depositional fluxes of ⁷Be and ²¹⁰Pb at Galveston during this period varied by a factor of about 2.5, between 8.9 and 23.2 disintegrations per minute (dpm) cm⁻² yr⁻¹, with a mean of 14.7 dpm cm⁻² yr⁻¹ for ⁷Be, and 0.67 and 1.71 dpm cm⁻² yr⁻¹, with a mean of 1.03 dpm cm⁻² yr⁻¹ for ^{210 …}

Petrology And Geochemistry Of Some High Pressure Rocks From Northern Part Of Rio San Juan Complex, Dominican Republic, Khandaker I. Anam

FIU Electronic Theses and Dissertations

The Rio San Juan Complex is an important occurrence of high pressure/low temperature rocks in the circum-Caribbean region which contains both coherent blueschist units and two varieties of melange in the same area. The melanges contain a diverse assemblage of blocks of various sizes, different degrees of metamorphism, and mineral assemblages. Some high pressure blocks show two stages of metamorphism. The earliest stage is characterized by high pressure-low temperature conditions and the second stage is characterized by high pressure-lower temperature conditions. The geochemistry of thirteen samples from the Rio San Juan Complex has been studied and data have been compared …

An Integrated Surface And Borehole Seismic Case Study: Fort St. John Graben Area, Alberta, Canada, Ronald C. Hinds, Richard Kuzmiski, Neil Lennart Anderson, Barry R. Richards

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

The deltaic sandstones of the basal Kiskatinaw Formation (Stoddard Group, upper Mississippian) were preferentially deposited within structural lows in a regime characterized by faulting and structural subsidence. In the Fort St. John Graben area, northwest Alberta, Canada, these sandstone facies can form reservoirs where they are laterally sealed against the flanks of upthrown fault blocks. Exploration for basal Kiskatinaw reservoirs generally entails the acquisition and interpretation of surface seismic data prior to drilling. These data are used to map the grabens in which these sandstones were deposited, and the horst blocks which act as lateral seals. Subsequent to drilling, vertical …

An Integrated Surface Seismic/Seismic Profile Case Study: Simonette Area, Alberta, Ronald C. Hinds, Neil Lennart Anderson, Richard Kuzmiski

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

On the basis of conventional surface seismic data, the 13-15-63-25W5M exploratory well was drilled into a low-relief Leduc Formation reef (Devonian Wood-bend Group) in the Simonette area, west-central Alberta, Canada. The well was expected to intersect the crest of the reef and encounter about 50-60 m of pay; unfortunately it was drilled into a flank position and abandoned. The decision to abandon the well, as opposed to whipstocking in the direction of the reef crest, was made after the acquisition and interpretive processing of both near-and far-offset (252 and 524 m, respectively) vertical seismic profile (VSP) data, and after the …

Probable Glacial Climatic Conditions In Source Areas During Deposition Of Parts Of The Ash Hollow Formation, Ogallala Group (Late Tertiary), Of Western Nebraska, Patricia E. Helland, Robert F. Diffendal Jr.

Robert F. Diffendal, Jr., Publications

Evidence of the climatic conditions in the mountain sediment source areas for the late Tertiary Ash Hollow Formation of the Ogallala Group in western Nebraska has been sought in an SEM (scanning electron microscope) study of surface features on detrital quartz grains from these deposits. The following lines of indirect evidence raised the possibility of glacial conditions: uplift of up to 3500 m in the source areas, paleohydrologic parameters indicative of a transport system analogous to the modern North Saskatchewan River, and possible cold climate surface features on cobbles from the deposits. SEM analysis shows that five of the nine …

Mapping The Distribution Of Vesicular Textures On Silicic Lavas Using The Thermal Infrared Multispectral Scanner, Jaime Ondrusek, Philip R. Christensen, Jonathan Fink

Geology Faculty Publications and Presentations

The Thermal Infrared Multispectral Scanner (TlMS) is a potentially powerful tool for mapping detailed chemical variations in silicic lava flows which in turn could expand knowledge of pre-eruption compositional gradients and mixing processes in silicic magma bodies. However, thermal infrared image data may be greatly influenced by the range of vesicular textures which occur on silicic flows . To investigate the effect of vesicularity on TIMS imagery independent of chemical variations, we studied Little Glass Mountain at the Medicine Lake Volcano of northern California, a large rhyolitic flow of uniform composition but textural heterogeneity. The imagery was recalibrated so that …

Chloroform Contamination In The Louisville Aquifer: An Investigation Of Its Occurrence And Propagation, Sergio E. Serrano

KWRRI Research Reports

This report presents the main results of an investigation on the nature and propagation of an accidental spill of chloroform in the Louisville aquifer, Kentucky. Much of the effort is concentrated on the development of mathematical models to either reconstruct the history of evolution of the plume, or forecast its propagation in the future. Chloroform is a dense halogenated solvent which exhibits a special migration pattern in porous media: Because of this and the relative absence of a conceptual theory on its hydrodynamics in porous media, meaningful predictive models will have to deal with many unresolved theoretical aspects of contaminant …

An Overview Of Some Of The Large Scale Mechanisms Of Salt Dissolution In Western Canada, Neil Lennart Anderson, Ralph W. Knapp

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Well log and seismic data indicate that the bedded rock salts of the Devonian Prairie Formation were widely distributed and uniformly deposited in the Lloydminster area, Western Canada; however, as a result of extensive leaching, the distribution of these salts is not now what it once was. The Lloydminster area is now bisected by the north-south trending main dissolutional edge of the Prairie salt. Thick salt (up to 150 m) is preserved to the west of this edge; to the east the salt is mostly absent. The paper presents an overview of the envisioned principal mechanisms of salt dissolution. The …

Odp Leg 146 Examines Fluid Flow In Cascadia Margin, Bernard A. Housen

Geology Faculty Publications

For the better part of 2 decades, it has been known that dewatering of sediments accreted to or subducted beneath accretionary wedges is a fundamental aspect of the subduction-accretion process. Yet, evidence for fluid flow in modern accretionary wedges is largely secondary and based on the presence of geochemical and/or thermal anomalies [e.g., Vrolijk et al., 1991]; the analysis of seismic velocity as an indicator of porosity, which suggests a progressive loss of pore volume in a landward direction [e.g., Bray and Karig, 1985]; and the occurrence of secondary sediment microstructures characteristic of fluid movement [e.g., Maltman et …

Evolution Of The Naticid Gastropod Predator-Prey System: An Evaluation Of The Hypothesis Of Escalation, Patricia H. Kelley, Thor A. Hansen

Geology Faculty Publications

Previous work has suggested that escalation may have characterized the history of the naticid gastropod predator-prey system, based on apparent increases in drilling frequencies and the occurrence of antipredatory aptations among prey. We evaluate this hypothesis based on a comprehensive survey (over 40,000 specimens) of predation on molluscs from the Upper Cretaceous through lower Oligocene formations within the U.S. Gulf and Atlantic Coastal Plain. Patterns in drilling of both bivalve and gastropod prey are complex. Drilling frequencies were relatively low in the Cretaceous but increased sharply above the Cretaceous-Tertiary boundary, remaining high until the late Eocene. Following a significant decline …

Geology, Geologic Time And Nebraska, Marvin P. Carlson

Conservation and Survey Division

No abstract provided.

A Model Of The Hydrothermal System At Casa Diablo In Long Valley, California, Based On Resistivity Profiles And Soil Mercury Analyses, John David Arfstrom

FIU Electronic Theses and Dissertations

A description and model of the near-surface hydrothermal system at Casa Diablo, with its implications for the larger-scale hydrothermal system of Long Valley, California, is presented. The data include resistivity profiles with penetrations to three different depth ranges, and analyses of inorganic mercury concentrations in 144 soil samples taken over a 1.3 by 1.7 km area. Analyses of the data together with the mapping of active surface hydrothermal features (fumaroles, mudpots, etc.), has revealed that the relationship between the hydrothermal system, surface hydrothermal activity, and mercury anomalies is strongly controlled by faults and topography. There are, however, more subtle factors …

Paleomagnetism And Tectonics Of The Crescent Formation, North Olympic Mountains, Washington, Andrew C. Warnock, Russ R. Burmester, David C. Engebretson

Geology Faculty Publications

A stable prefolding magnetization has been discovered in pillow basalts of the Eocene lower Crescent For­mation of the northem Olympic Mountains. The curved outcrop pattern of the Crescent Formation has been the target of several unsuccessful studies to test for oroclinal bending. The success of this study is due, in part, to the development of a small-diameter electric core drill for sampling the fractured rims of basalt pillows. Thermal demagnetization produced stable endpoints by 580°C in 12 of the 34 sites sampled (large within-site scatter was common in the remaining sites). Among the accepted sites, within-site scatter was small and …

Acoustic Properties Of Fine‐Grained Sediments From Emerald Basin: Toward An Inversion For Physical Properties Using The Biot–Stoll Model, Robert C. Courtney, Larry A. Mayer

Affiliate Scholarship

Acoustic data from two long cores, comprising marine clays and silts taken from Emerald Basin off Nova Scotia, are presented. High‐resolution measurements of compressional wavevelocity,attenuation, and power law exponent are made using ultrasonic frequencies between 100 to 1000 kHz. The observed values of the frequency dependence of attenuation suggest that a nonconstant Q mechanism is needed to explain these data, and Biot–Stoll theory is used to model the experimental results. An inversion scheme is used to constrain physical parameters in the Biot–Stoll dispersion relation. The inversion shows that there is a restricted range of permeability and grain size. By assigning …

Information And Regulations Pertaining To Industrial Minerals In Nebraska, Raymond R. Burchett

Conservation and Survey Division

No abstract provided.

The Health And Short-Term Change Of Two Coral Patch Reefs, Fernandez Bay, San Salvador Island, Bahamas, H. Allen Curran, Durelle P. Smith, Lucy Chambers Meigs, Ann E. Pufall, Mary Lisa Greer

Geosciences: Faculty Publications

Two coral patch reefs on the leeward shelf of San Salvador Island have been studied with surveys in 1983-84 and 1992 to monitor their ecological health and short-term change. Snapshot Reef covers an area of 50 x 50m and is dominated by Montastrea annularis. The reef was mapped in detail to show the position and size of its coral heads and 64 of these heads were studied in detail. To describe the reef, measurements were made of the height of each head, percent live coral coverage, the dominant coral species, total number of coral species present, M. annularis morphotypes presents, …

The Mobrup Catchment Working Plan - A Resource Inventory And Strategies, Steven Garrad

Soil conservation survey collection

The Mobrup LCDC has persevered for three years with its efforts to produce a catchment plan. They readily acknowledge that their work is just beginning as they now wrestle with this working plan to form something which will have application on each individual's enterprise to ensure a sustainable future for this catchment.This report is a collation of their ideas, an inventory of works done in the catchment and the best advice which research and local knowledge can provide.

Westhazel General Petroleums Pool: Case History Of A Salt- Dissolution Trap In West-Central Saskatchewan, Canada, Neil Lennart Anderson, Dale A. Cederwall

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

The Westhazel General Petroleums (GP) Pool of west-central Saskatchewan, Canada, produces from the GP member of the Lower Cretaceous Mannville Group. This reservoir is structurally closed across the updip, eastern dissolutional edge of the underlying Middle Devonian rock salt of the Leofnard Member, Prairie Formation. The leaching of these salts occurred in post-Mannville time in the Westhazel area and caused the regional southwest dip of the General Petroleums member to be locally reversed.The Westhazel GP Pool, from a geophysical perspective, is characteristic of many of the shallow Lower Cretaceous pools situated along the dissolutional edge of the Prairie salt. The …

Paleomagnetic Evidence Of Vertical Axis Block Rotations From The Mesozoic Of Northern Chile, Paul D. Riley, Myrl E. Beck Jr., Russ R. Burmester, Constantino Mpodozis, Alfredo Garcia

Geology Faculty Publications

We present paleomagnetic results for three Mesozoic formations from northern Chile: La Ternera Formation (Upper Triassic), Quebrada Monardes Formation (Upper Jurassic); Cerrillos Formation (Upper Cretaceous). Results from the Cerrillos are divided into eastern (Cuesta El Gao (CEG)) and western (Elisa De Bordo (EBD)) localities. Most specimens from La Ternera volcanic and sedimentary rocks are mag­netically stable, as shown by alternating field and thermal demagnetization. More complicated but still reliable results were obtained from Quebrada Monardes red beds. Normal and reverse polarities are present in both units; means of both populations are antiparallel at 95% confi­dence. The Quebrada Monardes Formation also …

Age Determination Of Recent Cave Deposits Using Excess 210Pb - A New Technique, M. Baskaran, Thomas M. Iliffe

Environmental Science and Geology Faculty Research Publications

Cave deposits have been widely used as proxy recorders in deciphering palaeoclimate during the last glacial/interglacial maxima (∼ 120 ka) [Harmon et al., 1975; Atkinson et al., 1978; Goede and Harmon, 1983; Ayliffe and Veeh, 1989]. Palaeoclimatic studies of cave deposits for the past 1–1000 yr time scale require a precise dating technique, that until now has been lacking. Due to the multiple sources of carbon in speleothems, ¹⁴C dates obtained for recently deposited calcite are highly variable and thus, ¹⁴C dating techniques are not suitable to obtain speleothem ages for the past 1–1000 years.

Here, we show …

Flat Water: A History Of Nebraska And Its Water, Robert D. Kuzelka, Charles A. Flowerday, Robert N. Manley, Bradley C. Rundquist, Sally J. Herrin

Conservation and Survey Division

No abstract provided.

Understanding Groundwater Starts With The Rocks: Geologic Fralnework, Groundwater Occurrence And Irrigation Development In Nebraska, Robert F. Diffendal Jr.

Robert F. Diffendal, Jr., Publications

Nebraska is blessed with abundant groundwater. This groundwater is found beneath much of the state, principally in the sediments and sedimentary rocks that blanket the ancient and largely crystalline rocks geologists call Precambrian (see block diagram of Nebraska's geology, p. 50). These younger deposits contain pieces of evidence such as fossils and sedimentary features that reveal the tremendous changes in the environment that have gone on over the last 570 million years, during which these deposits accumulated. Change is the name of the game in geologic history, just as it is in human history. Fundamental changes in geologic history across …

Profiles: Nelson Horatio Darton: His Surveys Laid The Foundation, Robert F. Diffendal Jr.

Robert F. Diffendal, Jr., Publications

No serious researcher studying the development of water resources in Nebraska, or for that matter in the central Great Plains, can overlook the works of Nelson Horatio Darton, the first geologist to study and publish about those resources in any detail. Darton originally published the names and characteristics of many hydrogeologic units beneath much of Nebraska, now used by groups as diverse as scientists, well drillers and the general public. These works are listed below. As an indication of the value of these early efforts, I have used these works for my research and can testify to their accuracy and …

Shapes Of Venusian "Pancake" Domes Imply Episodic Emplacement And Silicic Composition, Jonathan H. Fink, Nathan T. Bridges, Robert E. Grimm

Geology Faculty Publications and Presentations

The main evidence available for constraining the composition of the large circular "pancake" domes on Venus is their gross morphology. Laboratory simulations using polyethylene glycol show that the height to diameter (aspect) ratios of domes given total volume depend critically on whether their extrusion was continuous or episodic, with more episodes leading to greater cooling and taller domes. Thus without observations of their emplacement, the compositions of venusian domes cannot be uniquely constrained by their morphology. However, by considering a population of 51 venusian domes to sent a sampling of many stages during the growth of domes with comparable histories, …

The Origin And Evolution Of The Southern Snake Range Decollement, East Central Nevada, Allen J. Mcgrew

Geology Faculty Publications

Regional and local stratigraphic, metamorphic, and structural constraints permit reconstruction of the southern Snake Range extensional deformational system in east central Nevada. The dominant structure of the range, the southern Snake Range décollement (SSRD), operated during Oligocene and Miocene extensional deformation to exhume a footwall of multiply deformed metasedimentary and plutonic rocks. Intrusion of three plutons (∼160 Ma, 79.1 ± 0.5 Ma, and 36 ± 1 Ma, respectively) and development of two cleavages preceded the onset of extensional deformation. Plastic deformation of lower plate metasedimentary rocks accompanied the early phases of regional extension and produced bedding-parallel grain shape foliations and …

Calculation Of Acoustic Parameters By A Filter-Correlation Method, Robert C. Courtney, Larry A. Mayer

Affiliate Scholarship

This paper presents the filter correlation method, a technique for extracting consistent and accurate estimates of attenuation parameters from acoustic waveform data. The method minimizes problems associated with short time windows and multipath secondary arrivals. The method comprises two stages: a causal passband filter stage followed by a cross-correlation step. The results of the filter-correlation estimator are compared to those of the spectral difference approach for short time series with and without a secondary multipath arrival. Preliminary analyses of acoustic data collected on cored marine silts and clays show the attenuation properties of these materials cannot be described by a …

Geological Field Guide To The Cedar Point Biological Station, Keith County, Nebraska, Robert F. Diffendal Jr., Roger K. Pabian

School of Natural Resources: Faculty Publications

This field guide was produced by staff members of the Conservation and Survey Division of the University of Nebraska originally in 1979 at the request of Dr. Brent Nickol, former Director of the Cedar Point Biological Station. It is an introduction to the geologic history and paleoecology of the Cedar Point area intended for students, staff, and other persons using the camp. This revision has been made some 15 years after the first version to reflect changes in ideas resulting from new data collected during that time.

Users of this guide should take care when studying the rock exposures described …