The Philip M. Smith Graduate Research
Grant for Cave and Karst Research
2013 Grants
David Decker ($3,000)
Ph.D. Candidate
Department of Earth and Planetary Sciences
University of New Mexico
Effects of Landscape Evolution on the Growth of Sub-aqueous Speleothems - Rise of the Guadalupe Mountains
Abstract - The timing of the
rise of the Guadalupe Mountains is in dispute. One model suggests they
didn't reach their present height until recently, during the Rio Grande
rifting. A second model suggests that the Laramide orogeny was the
culprit for the major uplift. I suspect there were three instances of
mountain building, and a combination of the three led to the present 2
km+ height of the Guadalupe Mountains.
A new technique that will better constrain the orogenic episodes will
be tested in the Guadalupe Mountains to evaluate its effectiveness in
determining the timing and magnitude of the uplift events. By
correlating the growth of speleothems (specifically scalenohedral dog
tooth spar) both temporally and spatially with the injection of basalt
dikes in the region, we can develop a proxy for the timing and uplift
of the mountains. Using radiogenic isotopes (U, Th & Pb) to
determine the age of the cave formations, and stable isotope analysis
of fluid inclusions to gain information on temperature of formation and
formation waters as well as chemical signatures of the intrusive
igneous rocks in the region, we can develop a method for correlating
the growth of the sub-aqueous speleothems with the igneous intrusions
and from there determine the processes that may have been occurring at
the surface during the growth of the spar as well as the timing of
these processes.
This method may be expanded by use of vein filling and nail head spar,
and will be a valuable process for determining landscape evolution in
other areas of the country, specifically the Colorado Plateau, the
Ozark Mountains and the Black Hills.
________________________________________
John DeDecker ($1,500)
M.S. Student
Geological Sciences
University of North Carolina, Chapel Hill
Correlating Lava Tube Morphology with the Petrologic Characteristics of the Host Rock
Abstract- There is an inverse
relation between length and viscosity in the Hagen-Poiseuille equation
used to model tube confined flow. Lava viscosity is related to the
compositional and textural properties of the lava. Lava viscosities can
be estimated from subsolidus basalts using the compositional and
petrographic properties of the rock and methods developed by Marsh
[1981], McBirney and Murase [1984], Ishibashi and Sato [2007], Giordano
et al. [2008].
According to the Hagen-Poiseuille equation there should be a
correlation between lava tube morphology (length in particular) and the
petrographic and petrologic characteristics of the lava that solidified
at the time of tube formation. This study seeks to determine whether
such a correlation exists by estimating the viscosity of the lava using
compositional and textural data acquired from samples collected from
lava tubes, and by constructing 3D maps to constrain the length,
radius, and slope of sampled lava tubes. It is expected that longer
lava tubes will be correlated with rock compositions and petrographic
textures indicative of lower viscosity lavas, and shorter lava tubes
will be correlated with compositions and textures indicative of higher
viscosity lavas.
________________________________________
Christopher Myers ($2,800)
M.S. Student
Department of Earth and Environmental Sciences
Vanderbilt University
Paleoseismology of the Shillong Plateau, India: Constraints from U/Th dating of tectonically broken cave deposits
Abstract - Recent uplift of
the Shillong Plateau in northeast India has produced numerous mega
earthquakes such as the estimated 8.7 magnitude Great Assam Earthquake
of 1897. Previous paleoseismic research of Shillong Plateau has relied
upon radiocarbon techniques to date organic material found in
liquefaction features created by large seismic events. A lack of
observable surface ruptures on the plateau, 50,000yr-dating limit, and
large age uncertainties (~150yrs) limits the accuracy as well as the
temporal (~2,000 years) and spatial span of this paleoseismic approach.
Broken cave deposits (speleothems) can experience various forms of
breakdown during seismic events such as sub-horizontal fracturing and
collapse of stalagmites as well as fracturing of thin soda straw
stalactites. U-series dating of carbonates such as speleothems allows
breakage events to be dated more accurately over longer time scales
(500,000yrs) than previously possible with radiocarbon techniques. An
initial U-series analysis has produced errors of +/- 65 years for a
15,000-year-old aragonite stalagmite from the plateau suggesting
thatspeleothems from this region can be dated with high precision.
Using broken speleothems aspaleoseismic archives allows for a more
precise way to date paleoseismic events and estimate reoccurrence
intervals more accurately. I propose to constrain speleothem breakage
events caused by mega earthquakes on the Shillong plateau using
U-series dating techniques. If successful my proposed research would
greatly increase the current record of seismic events in northeast
India, and provide invaluable risk assessment information for the
people of northeast India and Bangladesh.
________________________________________
Daniel Nedvidek ($1,500)
M.S. Student
Department of Geography and Geology, Hoffman Environmental Research Institute
Western Kentucky University
Evaluating the Impact of Injection
Wells and the Effectiveness of Regulatory Sampling Protocols for
Stormwater on Groundwater Quality in Karst Regions
Abstract -The City of Bowling
Green (CoBG) is situated on a karst landscape, typified by a lack of
surface streams, numerous sinkholes and thin soils. The lack of surface
streams in the Bowling Green area, combined with thin soils, makes the
cave systems in the area natural candidates for stormwater runoff
control through the use of injection wells, which direct water into
underground streams and aquifer systems. Understanding the impacts of
Class V injection wells on groundwater is necessary, as these
unfiltered, uncased wells are allowable under EPA regulation as long as
they do not impair underground sources of drinking water (USDW),
including those sources currently under use and those that could be
used in the future (US EPA 40CRF 144.3). Although the CoBG primarily
obtains its drinking water from the Barren River, which has significant
karst spring inputs, the entire watershed is impacted by urban and
agricultural land use impacts both upstream and down. Under the Safe
Drinking Water Act and the Federal Underground Injection Control
Program, preventing the contamination of the CoBG's groundwater is
important for regulatory compliance, and also for downstream users and
the overall health of the ecosystem. While results from previous
studies suggest that the harmful stormwater runoff and the use of
injection wells to control that runoff are mitigated by dilution
provided by the Lost River, we expect to show that expanding population
and changing land use make stormwater runoff a much more credible
threat to groundwater quality than it has been in the past.
________________________________________
Nicole Ridlen ($1,000)
M.S. Student
Department of Geosciences
Mississippi State University
Speleothem Strontium Concentrations as a Function of Aragonite/Calcite Inversion
Abstract -The presence of
strontium (Sr) in carbonate rocks has documented and has been
recognized as a contributor to the trace element content of speleothems
used for paleoclimate reconstruction. The Sr in speleothems can
originate from multiple sources although the majority of Sr analysis in
speleothems has been assumed to be infiltrated from a surface. The
aragonite crystal structure allows for a greater amount of Sr to exist
in the bedrock. It is hypothesized that younger carbonates, such as
those in the Caribbean, can contain more Sr than older carbonates that
have already inverted to calcite prior to cave formation. Island
carbonates, such as the carbonate units deposited as aragonite on
Curacao, are terraced where the oldest unit is on top and inland, and
the youngest on the bottom and seaward. Samples from Bahamian caves of
similar age should provide a comparison with a climatic variant.
Three questions are to be asked during this research. One: Does the
primary aragonite content of the young carbonate host rock register as
the Sr content of Caribbean speleothems and have a direct relationship
with the age of the host rock at the time of precipitation? Two: Do
older speleothem layers contain less Sr than younger speleothem layers
in the same climatic setting from young carbonate host rock with the
same initial primary aragonite content? Finally, three: is there a
variation in the primary aragonite content and hence Sr content, of
speleothems in young carbonates of the same age but from different
climates?
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last updated or validated on January 26, 2019