Undergraduate
and Graduate Research Symposium
Department of Geological Sciences
Friday February 22, 2002, 4:30
– 7:30 pm
As a way to communicate
the breadth of research interests in the Department of Geological Sciences,
this symposium opens an informal and friendly space to for shareing current research
ideas, explain approaches being
used inour current research projects, and present preliminary results. We encourage graduate and senior
undergraduate students to participate in this event, and we will really appreciate
any faculty/KGS assistance and input.
4:30 Introduction
4:35
Characterizing Sediment Transport through an Inner Bluegrass Karst
Aquifer
Todd McFarland
4:50
Implications in
syntectonic deposition and structural analysis of the thrust belt of basement
faults in the southernmost Appalachians
5:05
Metamorphic and Fabric evolution of rocks defining the Hayesville
fault, western North Carolina
Matthew Allan Massey
5:20
break
5:30
The Alleghanian Orogeny: Reducing, Reusing and Recycling
5:45
Investigating the geologic history of the Kentucky River
William "Drew"
Andrews
6:00
Characterization of fluvial sediments above two economically
important coal seams within the Breathitt Group, southeastern Kentucky
Michael G. Shultz
6:15 break
6:25
Modeling Pseudotachylytes in Fault zones
Ravi Kanda
6:40
Identification of Natural Attenuation of Trichloroethene and
Technetium along Little Bayou Creek, Kentucky, by Tracer Tests
6:55 next symposium,
brown-bag seminars, etc…..
7:10 FOOD
Characterizing Sediment Transport through an Inner
Bluegrass Karst Aquifer
Todd McFarland
The characterization of sediment transport through a karst
aquifer can reveal possible vectors for contaminant transport as well as
sediment provenance (i.e. urban vs agricultural). The Blue Hole karst groundwater basin is located in the
Versailles 7.5 minute quadrangle in Woodford County, Kentucky. Blue Hole spring emerges at a sewage
treatment plant due west of downtown Versailles. Previous dye traces in the area (Currens, Ray, and Paylor)
have shown that sources for recharge include Big Spring (a sinking stream
located in downtown Versailles), and a sinkhole located on a farm approximately
1 km southeast of downtown. A
future qualitative dye trace will determine if the sinkhole discharges directly
to Blue Hole or Big Spring. In
order to characterize discharge at Blue Hole spring, stream stage and
temperature are monitored continuously with a thermistor and pressure
transducer in a stilling well connected to a data logger. Weekly discharge measurements are also
recorded using a Marsh-McBirney flow meter and a top-setting rod. Stream stage will then be correlated to
discharge building upon a preliminary discharge rating curve developed by J.C.
Currens (KGS). Specific
conductance and pH are also measured weekly with portable meters. During a
storm event analyses of total
suspended sediment concentration, grain size, mineralogy, particulate organic
carbon, specific conductance, pH, spring temperature, and discharge will be
measured at Blue Hole spring. During low flow, sediment from the Big Spring
sinkhole, the farm sinkhole, and Blue Hole spring was collected for analyses of
grain size, mineralogy, and particulate organic carbon for comparison with the
suspended sediment. During a
recent high flow event, a Rhodamine WT quantitative dye trace was conducted
form Big Spring to Blue Hole spring to observe dye travel time at storm flow
stage levels and to calculate the % and mass of dye recovered. A quantitative trace, pending results
of the qualitative trace from the farm sinkhole, will involve a simultaneous
trace from Big Spring and the farm sinkhole during storm flow to characterize
the sediment as urban or agricultural in origin.
Implications in syntectonic deposition and structural analysis of the thrust belt of basement faults in the southernmost Appalachians
Basement faults are weak zones in the continental crust, and any subsequent deformation may be expected to utilize these zones affecting either the evolution of sedimentary basins or orogenic belts. Seismic reflection profiles across the thin-skinned southern Appalachians thrust belt document a complex intraplate basement graben system beneath of the regional décollement. The questions are if these intraplate basement faults were reactivated during later contractional events and controlled the geometric and kinematic evolution of the advancing orogenic belt.
Comparison of Cambrian and Ordovician strata across basement
faults indicates an episode of inversion of the graben system. Lower Cambrian
syn-rift strata consist of thick fine-grained siliciclastics with thin
carbonate deposits in the depocenter of a half-graben, whereas thin
shallow-marine carbonate deposits dominate in the shoulders of the graben. During the Taconic orogeny, uplift of
the former graben enhanced deeper erosion of passive-margin deposits, and restricted the cratonward progradation of the clastic wedge
to the southeast and favored carbonate deposition to the northwest. Analysis of Silurian to Pennsylvanian
strata has documented other events of fault reactivation during subsequent
orogenies.
The
interactive analysis of the structural configuration of the top of basement
(rifting + inversion + several events of flexure) and the internal architecture
of Paleozoic deposits (synrift + passive margin + composite foreland strata) is
an important approach to interpret the geometry and kinematics of the thrust
belt. Low-amplitude fault-related
anticlines form where the top of basement is shallow and nearly flat,
high-amplitude fault-related anticlines form where the regional
décollement is within the basement graben; detachment folds are
nucleated above down-to-southeast basement faults with moderate vertical slip;
and a mushwad evolves above broad grabens bounded by basement faults with large
vertical slip and containing a large volume of weak strata. Curvatures of the thrust belt (i.e.,
deviations in strike of folds and faults) are genetically related to changes in
basement topography across basement transverse faults. Because basement faults control both
syntectonic deposition and structural style of thrust belts, combined
stratigraphic and structural analysis may indirectly constrain the location of
basement faults in areas with inaccessibility to observation or with
difficulties in interpreting geophysical data.
Metamorphic and Fabric evolution of rocks defining the
Hayesville fault, western North Carolina
Matthew Allan Massey
I will be talking about the supposed
Taconic suture, past interpretations, observations from field work and
petrographic analysis thus far, present conclusions, and future work.
The
Alleghanian Orogeny: Reducing,
Reusing and Recycling
Thomas
Becker
Classic studies of the sedimentary
sequences in the Appalachian-Ouachita foreland basins infer a provenance from
an exhumed hinterland related to Paleozoic orogenic activity. Based on measurements of paleocurrent,
distribution and coarseness of clastic sediments and facies relationships, this
seemed to be an immutable conclusion.
However, recent applications of U-Pb dating to detrital zircons and
radiogenic Nd isotopic ratios within the Late Paleozoic Appalachian foreland
sequences suggest that the sediment is derived wholly from Laurentian crust,
with no component from a convergent arc or Gondwana-like collider. This interpretation may require
sediment transport in a manner inconsistent with field evidence. Calculations of the mass balance of Nd
isotopic composition from a Grenville-like basement and continental arc
indicate that Nd isotopes are not particularly sensitive for analyzing
provenance, but instead give information of the nature of the continental crust
involved in the orogenic process.
Resolution
of the detrital zircon ages and Nd isotopic signatures in the
Appalachian-Ouachita sedimentary basins is critical to aid in the understanding
of continent-continent collisional belt evolution and associated crustal
growth. Our current proposal seeks
to re-evaluate the existing data on detrital white mica and attempt to resolve
the detrital zircon ages and Nd isotopic data with sedimentological
inferences. Some possible areas of
study include sampling volcanic fragments within Pennsylvanian-Permian
sedimentary rocks for bulk and trace element analysis and (age determination?)
or seeking out other methods with volcanogenic minerals.
Investigating the geologic history of the Kentucky River
William
"Drew" Andrews
The
focus of my dissertation research is on the geological history of the Kentucky
River through the Bluegrass Region of Kentucky. A thorough understanding of
river history can serve as a foundation for applied studies in water supply,
hydrology, sedimentology, fluvial geomorphology, archaeology, soil science, and
slope stability.
The
Kentucky River has incised more than 300 feet into the Bluegrass plateau across
which it flows. Geological mapping by earlier workers had identified at least
three levels of the river near its present course. The modern floodplain has
been modified by recent human engineering of river pools. Low-level gravel deposits and terraces
preserve a relatively young stage of the river deep within its current valley.
High-level deposits record an early stage of the river before incision into the
plateau, known as the Old Kentucky River. Radiometric dating on sediments at
the Kentucky River headwaters and in the Green River valley suggest an age of
approximate 1.5 Ma for this stage of the river. Based on sedimentological
evidence, one worker has hypothesized ancient river courses (pre-Old Kentucky
River) across the Bluegrass plateau connecting the upper portions of the
Kentucky River valley with the South Fork of the Licking River or North Elkhorn
Creek.
One
step in sorting out the history of the river will be to identify the trends and
elevations of terraces and related river corridors. Terraces are, in the most
general sense, abandoned floodplains and record periods of river stability or
aggradation. An examination of sediment composition and potential sediment
source areas can help to constrain models of fluvial evolution and test
hypotheses of ancient river courses. To calibrate the rates of evolution of the
system, radiometric dating of some features or events is desirable.
Unfortuanetly, no one definitive or easy technique exists for dating young
geologic features. Cosmogenic isotopes provide one potential tool for
approaching the problem, however, and may allow dating of fluvial deposits,
erosion surfaces, or related karst deposits.
Characterization of fluvial sediments above two
economically important coal seams within the Breathitt Group, southeastern
Kentucky
Michael G. Shultz
One
concern in underground mining is post-mire fluvial systems, and how they affect
roof control in underground coal mines.
Fluvial systems, subsequent to peat accumulation, can have a significant
affect on mining conditions by placing low strength sediment packages above coal
deposit within the roof strata.
Furthermore, differential compaction of mudstones around fluvial
sandstones can also adversely affect preexisting sediments.
Because
many paleochannels range from tens to hundreds of feet wide, standard drill
hole distributions of 1000 feet or greater may not be sufficiently dense enough
to detect them. Channel sinuosity further complicates the ability to detect
these deposits within the roof strata using only drill holes or mine
mapping. Thus, process models that
explain the causal mechanisms of channel development are useful for predicting
geometry where detailed data are missing.
The two most common process models are the stacking model and the offset
model, which look at the distribution of coal and siliciclastic bodies
throughout a stratigraphic section.
The
ultimate goal of this research is to predict the location and geometries of
fluvial sediments in the roof strata of a Lower Elkhorn coal reserve.
Unfortunately, in the proposed study area, there is relatively little
data for the Lower Elkhorn coal, especially historical mining data, that can is
critical to the synthesis of a process model. However, there is abundant historical mining data and drill
hole information for the Elkhorn No. 3 coal, a stratigraphically higher coal
seam that experienced similar problems with post-mire fluvial
sedimentation. Data for the
Elkhorn No. 3 extends back to World War II. It is our hope, then, that a detailed understanding of Upper
Elkhorn No. 3 post-mire fluvial systems and emplacement, for which there is an
abundance of data, may lead to an understanding and prediction of Lower Elkhorn
post-mire fluvial systems, and emplacement for which there are little data.
Modeling Pseudotachylytes in Fault zones
Ravi Kanda
I
will be talking about what pseudotachylytes (PT) are, what structures they can
be found in, what structural and observational constraints are available to us
for modeling to be feasible, how do you model the generation of PT, and how do
we expect to validate our model results.
Identification of Natural Attenuation of
Trichloroethene and Technetium along Little Bayou Creek, Kentucky, by Tracer
Tests
Little Bayou Creek is a first-order tributary to the Ohio
River in McCracken County, Kentucky. The stream receives inflow from an aquifer
contaminated by past waste disposal activities at the Paducah Gaseous Diffusion
Plant (PGDP) a US Department of Energy uranium enrichment facility and
Superfund site. Contaminants include trichloroethene (TCE), a suspected
carcinogen, and technetium-99 (99Tc), a radionuclide. The present
work involves identifying processes that may naturally attenuate contaminants.
I hypothesize that (1) these processes of natural attenuation include (a)
dilution, sorption, and volatilization for TCE and (b) dilution for 99Tc
and (2) dilution and volatilization of TCE vary seasonally.
The proposed study will include seasonal monitoring of the
surface and subsurface discharge in the creek. Surface discharge will be gauged
by the cross-section method (Rantz, 1982), which involves stretching a
measuring tape across the stream, perpendicular to the direction of the flow.
Measurement of depth and flow velocity of the vertical section across the
stream channel by flow meter at multiple points permits calculation of the
stream discharge at that location. In order to account for hyporheic-zone flow
and to monitor natural attenuation of TCE and 99Tc, seasonal tracer
tests will be run. Br-, a conservative tracer, will be introduced
into the stream as a slug of NaBr and used to measure total stream flow
(including underflow) at the gauging points. This will also give an estimation
of the attenuation of 99Tc by dilution, as this radionuclide tends
to occur as the TcO4- ion under aerobic conditions. Br-
concentrations will be measured by ion-selective electrode. Rhodamine WT dye
will also be injected with the NaBr slug to visually delineate the tracer
plume. Because the meta isomer of Rhodamine WT is prone to hydrophobic sorption
to sediment, the breakthrough curve for the dye will be compared with those of
Br- to infer the extent of TCE sorption to the stream sediments. Rhodamine WT
concentrations will be measured by fluorometry. Following addition of Br-
and the dye, propane (C3H8) will be constantly bubbled
into the stream as a non-conservative tracer to simulate the attenuation of TCE
by in-stream volatilization. The volatilization values of the propane will be
compared with a standard ratio to estimate the actual volatilization rate of
TCE . Propane concentrations will be analyzed by gas chromatography with a
flame ionization detector to measure concentration and hence to determine the
gaseous exchange rate of propane in the stream with the surrounding air.
Affects
of a Kimberlite intrusion on the vitrinite reflectance of the springfield (No.
5) coal, Harrisburg, IL
Alexander Stewart
The Springfield (No.5) coal
is a Pennsylvanian-age high-volatile-b-bituminous coal from the Carbondale
Formation presently being mined in the southeastern section of the Illinois
basin by the Arclar coal company.
Advected through this coal is a 10.1-meter-wide kimberlite dike that is
vertical, through extent of the mined coal seam, and striking ~158
degrees. We studied both the
intrusion and the affects it incurred on the coal. Through microscopic analysis it was determined that the
intrusion was of kimberlite composition with a lamprophyric texture that
subsequently underwent at least two stages of serpentinization. Using a heat flow model by Carslaw and
Jaegar (1959) in conjunction with microscope analysis, an insertion temperature
of ~6000C was determined. We also measured the vitrinite reflectance
of the coal from a suite of samples collected distal the intrusion. Vitrinite reflectance values rose
uniformly from the ambient reflectance values of ~0.69%, at just greater than
1-dike thickness away, up to >6% at the dike/coal contact. This increase in
reflectance values, proximal from ~1.2 times dike thickness, is concordant with
data put forth by Bostick, N.H., and Pawlewicz, M.J. (1984) in which they
studied the affects of mafic intrusions advected into Cretaceous-age shales in
Walsenburg, Colorado. Similarity
to their work suggests that despite intrusion temperature, timing, or coal rank
at time of the intrusion ambient reflectance values remain unchanged at just
greater than one-dike width away from an intrusion.
Pyrite framboid size and size
distribution: Indicators of anoxia
during deposition of Devonian-Mississippian black shales
Sarah Hawkins
The variation in both mean pyrite framboid size and
in framboid size distribution ranges in marine waters of modern environments
and ancient sediments have been used as valuable tools in determining redox
conditions (e.g., Wilkin et al., 1996, 1997; Wignall and Newton, 1998; Hoffman
et al., 2000; Wilkin and Arthur, 2001; Fisher and Wignall, 2001). Wilkin (1996) reported mean average
framboid diameters of 5.0 +/- 1.7µm for modern euxinic environments,
while mean framboid diameters of oxic and dysoxic environments were
considerably larger (7.7 +/- 4.1µm). Framboids that form within a euxinic water column also
exhibit narrower size ranges than those that form within anoxic sediment
porewater just beneath an oxygenated water column. Pyrite morphology (framboids, “infilled” or
“welded” framboids, euhedral crystals and masses) may also be
indicative of redox conditions of pyrite formation; Wilkin and Barnes (1997)
showed that framboids are the only pyrite morphology to form suspended within
an anoxic water column.
Three Devonian-Mississippian marine organic-rich
black shale units (the Sunbury Shale, the Cleveland Shale, and the Huron Shale)
comprise approximately 45m of the
D-6
core of east central Kentucky.
These units were compared in terms of pyrite morphology and framboid
size. Previous studies of carbon-sulfur-iron
relationships and trace element paleo-redox indicators for these sediments
suggest that euxinic conditions were more persistent during accumulation of the
Sunbury and Cleveland than during accumulation of the Huron (Rimmer, 2000). The pyrite morphology, framboid
size and size distribution were expected to vary accordingly.
Preliminary
results show mean diameters of framboids from these units are similar: the Sunbury had the smallest mean
average diameter of 4.75µm, the Cleveland had a mean of 6.19µm, and
the Huron had a mean of 5.5µm.
Differences, however, occurred in the range of diameters and in other
distinguishable characteristics, including extent of diagenetic pyritization and
presence of euhedral crystals.
Size distributions and modes of occurrence will be discussed in terms of
paleo-redox conditions during accumulation of these three units.