Water resources are subject to several stressors such as global climate change, land degradation and urbanization bringing unpleasant consequences to both natural and human systems. Scientific studies estimate that global climate change coupled with unmanaged development and 10+ billion people in the next few decades could degrade both the quality and quantity of water, especially in urban areas in various parts of the globe. Therefore, it is urgent to investigate how these stressors could impact water resources globally, regionally and locally. In this project, we aimed to estimate the impacts of climate change on streamflow by taking an example of the Village Creek River (VCR), located in Everman, Texas. For this, we constructed a hydrological model of VCR, which has a drainage area of 219 km2, by utilizing the Soil and Water Assessment Tool -SWAT. We used topographic, land cover, and soil maps along with historical climate data to drive the model. Then, we fed in climate projections from multiple global climate models to generate streamflow simulations representative of future climatic conditions, demonstrating changes to a local hydrologic cycle. We expect our modeling results would be useful to stakeholders and decision makers for making sustainable watershed management strategies to combat potential climate change risks.
Despite the negative connotation of urban sprawl for bat populations, fragmented green spaces such as parks, cemeteries, and golf courses have the potential to provide necessary resources for bats. For example, water sources in these areas can include lakes, ponds, streams, and drainage ditches. Such water resources, however, can be ephemeral when subject to prolonged periods of high temperatures and low precipitation. Yet, recent studies reveal that bat species are potentially able to adapt by using unconventional, anthropogenic-based resources, such as residential swimming pools. Thus, for those bats utilizing urban green spaces, we hypothesized that they would expand or shift their home ranges to access swimming pools as an alternative water source in the surrounding neighborhoods. To explore this hypothesis, we conducted a telemetry study tracking resident evening bats (Nycticeius humeralis) caught in a local park system across their summer activity period from 2017-2019 in Fort Worth, Texas, USA. Our results supported the proposed hypothesis, demonstrating that bats expanded their home ranges from the park system into the surrounding neighborhoods when average nightly temperatures exceeded ~30°C and total weekly precipitation was <1 in. Furthermore, we observed that the home ranges increased over 4 times in size under these conditions. Thus, our study indicates that urban neighborhoods surrounding green spaces can provide important alternative resources for bats, and if managed appropriately can contribute to and encourage healthy, stable bat populations.
The potential of cost-effective UAV technology to replace costly technologies in Precision Agriculture
The use of satellite and aerial remote sensing for agricultural applications has exponentially expanded since the past decades. One such agricultural application that is highly dependent on the use of advanced hyperspectral and multispectral remote sensing and GPS technology to boost crop harvests and viability, while reducing the number and amount of inputs, like water, fertilizer, land, and others required to grow crops, is Precision Agriculture (PA). Although PA has been credited for the increased crop yield and productivity in the United States and worldwide, its dependence on costly technologies has been a major hurdle for it to be used by small-scale farmers locally and globally. This project aims to reduce the dependence of PA on costly and complex remote sensing technologies through the use of alternate and cheaper options such as low/medium-priced Unmanned Aerial Systems (UAV), popularly known as drones, equipped with only high-resolution cameras capable of, to a certain extent, mimicking the functionalities that are offered by costly technologies. Such low-cost technology is anticipated to enhance the efficiency and profitability of the agriculture sector through the provision of easier technologies to small-scale farmers. The research project is currently being implemented on a wheat farm owned by Davis farms (Grandview, Texas). Multi-temporal (at different growing stages) UAV imageries using DJI Mavic air 3D are being acquired with the purpose of producing 3D maps for qualitative and quantitative analysis. This includes crop-health assessment through the generation of crop-health indicator indices such as the Normalized Difference Vegetation Index (NDVI). A similar analysis from high-resolution multispectral imagery of the area, acquired from commercial satellite operators, will be undertaken and the accuracy, validity, and reliability of the UAV-based PA application will be assessed.
The effects of increased population growth on Rwanda’s forest ecosystem.
Rwanda is a country in Central-East Africa and one of the smallest countries on the African continental, being only 10,169 mi²/ 26340 sq. Km. Rwanda is a landlocked country bordered by Uganda, Tanzania, Burundi, and the Democratic Republic of the Congo. The current population of Rwanda is 12,830,205 as of 2020, based on the latest United Nations data with a population density of 525 per Km2 which equates to about 1,360 people per mi2 with 17.6 % of the population living in urban centers.
Rwanda forests have historically played a very significant role in the economy and livelihoods of its population through tourism, energy, and other industrial purposes. They provide around 86% of the primary energy source mainly as domestic cooking energy. Rwanda experienced 50.9% total forest loss since 1990, in order to address this deforestation and imbalance in wood supply/demand, Rwanda has over the years taken a consistent stance on increasing the forest cover by 30% by 2020. With growing population, this case study is going to analyze how population growth in Rwanda has affected forest cover and biodiversity. The study will integrate available geospatial datasets such as census, infrastructure, and satellite imagery to assess the impact of population growth on deforestation.
Americans generate about 12.6 million kilograms of spent coffee grounds every day. 90% of that will end up in a landfill. However, this waste stream is a potential starting material that can be used for engineering purposes and to address issues like climate change and water pollution. For example, initial research has shown that charring (burning) the grounds at 350℃ improved its lead removal abilities. My research will convert spent coffee grounds to carbon-based materials by charring (burning) them at 350oC, 450oC, and 650oC to investigate how fast they can remove the lead. My research will also explore how activating the charred coffee grounds with nitric acid (HNO3) will enhance its capacity for lead removal and how the rate at which the materials can remove it.
Climate change and urbanization both have far-reaching impacts on our water resources. For example, increase in human population, rise in average global and regional temperature, and sporadic rainfall events will alter water supply, quality, and accessibility disproportionately across the globe. It is anticipated that stream discharge could decrease due to climate change, and potentially elevate stress on water resources and stream ecosystem in the Dallas-Fort Worth (DFW) area. In this project, we are developing a hydrological model using the Soil and Water Assessment Tool – SWAT to investigate how streamflow of Walnut Creek, with a drainage area of 196 km2 located in Reno, Texas could change due to projected change in future precipitation and temperature. The data used to drive the model include land cover, soil, and elevation maps, and historical daily climate data - precipitation, temperature. The model results will allow concerned stakeholders to make more informed decisions regarding water resources now, and in the future in the DFW area.
Human activities, mainly the release of greenhouse gases, have caused our climate to change at a rate faster than anything seen in the recent past. Across the contiguous United States (US) annual average temperature and precipitation have increased by 1.0 °C (1.8°F) and 4% respectively since 1900, with strong regional differences. In the future, annual average temperature is projected to increase by 1.3 – 6.1°C with increase in frequency and intensity of heavy precipitation events. Complicating climate change, the US population has also grown sevenfold since 1800 leading to unmanaged urban growth. Climate change and urbanization are likely to impair streamflow and stream ecosystem. This study aimed to develop and use a hydrological model to estimate changes in streamflow discharges under different scenarios of projected climatic conditions at the rural-urban fringe. For this, we selected the Clear Creek (USGS 08051500) with a drainage area of 764 km2 in North Central Texas and used the associated topographic, land, soil and weather data to develop a hydrological model of this sub-watershed utilizing Soil and Water Assessment Tool – SWAT and geographic information systems interface- ArcMap. We anticipate results will show longer periods of drought followed by higher intensity precipitation events leading to decreased flow in the Clear Creek outside of these larger precipitation events. The study results may provide useful insights into the relationship between climate change and streamflow in North Central Texas watersheds at the rural-urban fringe.
Herbicides are chemicals frequently used in agriculture to manage or remove unwanted vegetation (i.e., weeds) that may negatively impact crops through resource competition. Through the elimination of these competitors, losses in crop yield may be reduced thus increasing cropland productivity. Atrazine is an herbicide that is widely used in the United States for the control of weeds that is predominately applied in the agriculture of corn, sorghum, and sugarcane. This is of interest to Illinois agriculture, as according to the United States Department of Agriculture (USDA), Illinois is a major agricultural producer of corn and soybeans with corn accounting for 11 million of Illinois’ 27 million acres of cropland. Further, Illinois possesses an agricultural industry that produces more than $19 billion annually of which corn accounts for more than 50 percent. It is due to the economic importance of corn crops to the state of Illinois and the widespread use of Atrazine in the agriculture of corn, that this project seeks to examine the relationship between Illinois annual corn crop yields and Atrazine application. This relationship will be assessed through analysis of spatial data acquired from the USDA for Illinois Atrazine application and corn crop yield.
The Trans-Pecos igneous province (TPIP) spans much of west Texas and is mostly Eocene-Miocene in age. We have recently documented near-vent basaltic pyroclastic deposits > 10 m thick within fluvial strata of the Black Peaks Formation (BPF) containing Paleocene mammal fossils. These deposits crop out in a 1.2 km2 area in a remote part of Big Bend National Park within the southeastern portion of the TPIP. The northern margin of the pyroclastic succession is obscured by Eocene felsic intrusions, but elsewhere along the margins of the succession the deposits are overlain and underlain by terrigenous BPF strata and thin to the east. The deposits consist mostly of thinly bedded tuff, lapilli tuff, and lapillistone, with clasts < 1 cm across. Dispersed, poorly vesicular bombs < 1.1 m across with asymmetrical bomb sags also occur. Planar bedding and lamination are most common, but low-angle antidune-type cross-bedding occurs in some areas as well, indicating deposition from both pyroclastic fall and pyroclastic surges. In thin section, lapilli and ash have low vesicularity and fluidal or droplet-like to subangular and angular shapes. They mainly consist of light-brown altered sideromelane glass derived from rapid quenching of magma in contact with water. These characteristics indicate the pyroclasts were formed by explosive phreatomagmatic eruptions. Up to 20 % terrigenous quartz and feldspar silt and sand grains are intermixed with the juvenile pyroclasts and are sharply angular, suggesting that they were shattered during explosive subsurface interactions between uprising magma and groundwater-rich sediments. The pyroclastic deposits typically have gentle dips characteristic of ejecta rims around tuff rings, a common type of phreatomagmatic volcano. Over 20 mostly upright petrified tree trunks have been discovered within the deposits and show no signs of having been burned prior to fossilization, indicating pyroclastic surges were not hot enough to ignite the trees during their passage. Anomalously steep dips (up to 25o) in the pyroclastic deposits and adjacent parts of the BPF occur locally and likely represent collapse of parts of the succession due to development of one or more vents in weak, unconsolidated strata.
Increasing demands for efficient food production and
sufficient water supply in the face of a rapidly rising population
combined with potential negative impacts of climate change
necessitates best management strategies and improved resource
conservation efforts. This requires the mapping and model of the
geospatial variability in soil properties at significantly higher
resolutions than provided in current soil surveys. Central to these
issues is the idea of soil health and security which dictates that
soil should be treated as a valuable resource to be protected and
conserved. This requires the mapping and model of the geospatial
variability in soil properties at significantly higher resolutions
than provided in current soil surveys.
This study focuses on the use of electrical conductivity (ECa)
through the application of electromagnetic induction (EMI) to
model and map key soil properties such as clay content, water
content, and salinity, all of which are shown to drive a given soils
functionality for providing a desired ecosystem service. Deriving
these ECa –soil property relationships enables the non-invasive,
real time estimation of spatial and temporal soil variability.
This improved mapping capability will enhance the predictive
capabilities of current ECa modeling efforts by quantifying
heterogeneity in the XY and Z direction, a dimensional aspect that
had been largely ignored in previous studies. The combination of
the geospatial and temporal aspects of the models will also allow
us to study soil hydrology, geochemical dynamics, and
applicability to different land uses. Ultimate outcomes will
include achieving long term sustainability, subsurface
infrastructure stability, and increased agricultural productivity.
The Lower Cenomanian Maness Shale is a marine mudrock unit lying between the Buda Limestone and the Woodbine sandstones in East Texas and between the Buda Limestone and Eagle Ford shales in South Texas. The Maness has been studied since the 1950’s, yet much is still unknown, such as its sediment source, depositional environment, and source rock potential. This study focuses on the Maness Shale in its type area of East Texas, and encompasses biostratigraphic, mineralogic, elemental, and petrographic analyses from three East Texas cores in conjunction with well-log correlations. The biostratigraphic analyses uses age-diagnostic calcareous nannofossils and microfossils to determine if the East Texas Maness Shale is age-correlative to the mudrock identified as Maness near the San Marcos Arch. The mineralogic and elemental data analyzes the samples to determine bulk mineralogy, clay content, and elemental abundances of the mudrock for source rock and depositional environment interpretations. The petrographic analyses analyzes microfacies and depositional processes.
The findings were compared to data from a recent study that focused on the Maness Shale near the San Marcos Arch, and determined that the Maness Shale of East Texas is age-correlative. Log correlations were constructed across the Texas Shelf, assembling six regional cross-sections correlating the Maness Shale from East Texas to the Brazos Basin to further understand the sediment source and paleoenvironment that produced this Lower Cenomanian shale.
Analysis of Deforestation in Nilgiri Biosphere Reserve
This research will focus on Nilgiri Biosphere Reserve, a mountainous region located in the Western Ghats of southern India that encompasses several major national parks. Recent developments have caused mass deforestation in the region for lumber and area for plantations. In addition, more roads are being developed connecting urban centers to Nilgiri, which is only worsening the deforestation issue. In this research, Landsat satellite images will be used to track change over time with regards to deforestation and the development of road networks to see how that impacts wildlife. Geospatial data geoprocessing tools will be used to categorize change in land use over time (the change in some land areas from forest/untouched reserve to agricultural or road). False and true color composites in addition to Normalized Difference Vegetation Index (NDVI) assessments will be undertaken to track the deforestation and differentiate between land types, since vegetation will be in a bright red, soil will be brown, and urban areas will be cyan blue to determine how much live green vegetation there is in the reserve as well.
Assessing Land Use Impact on Urban Heat Island Formation in Fort Worth
This research project will focus on assessing the impacts of human activity on the environment in Fort Worth as urbanization has increasingly taken hold over the years. Specifically, the project focuses on analyzing the change in land use in the city over a span of roughly three decades and its contributions to urban heat island formation. Landsat band data products will be used to estimate variations in land surface temperature (LST). LST calculations will highlight the factors contributing to urban heat island formation in Fort Worth.
Iron oxides, amino- and non-amino carboxylic acids are prevalent in the environment where they play essential roles in controlling the movement of elements central to the regulation of our climate and environmental quality. The physical and chemical properties of iron oxides, as well as carboxylic acids, vary temporally and spatially. Capturing the impact of this variation is important in predicting the current and future environmental response to human-induced alteration to earth. My research looks at how the presence of amino acids as zwitterion influences the interaction with different iron oxides minerals compared to their non-amino counterparts. To understand these interactions, we study the sorbed quantity and kinetics of two non-amino carboxylic acids; acetate (C2H3O2Na.3H2O) and propionate (C3H5NaO2) and two amino acids; glycine (C2H4NNaO2) and L-alanine (C3H7NO2) onto the surface of synthetic analogs of naturally occurring iron oxides (e.g. ferrihydrite, goethite, and hematite) under pH conditions between 3 and 12. Results thus far show significant differences in the quantity sorbed and the rate of sorption. For example, the amount of non-amino acids increases with increasing pH on all iron oxides but different rates. In contrast, for the amino acids, the amount of L-alanine sorbed onto iron oxides decreases sharply with the increase in pH while glycine decreases more gradually with an increase in pH. My presentation will discuss the variation in surface properties of iron oxides and structural properties of carboxylic acids dictating observed differences in the sorption dynamics.
Anti-inflammatory drugs such as ibuprofen and triclosan are widely used and available in many pharmaceutical and personal care products (PPCP’s). The concentrations of these drugs are increasing in public surface and groundwaters and are often linked to negative impacts on aquatic life. These impacts are due to the fact that PPCP’s bypass water treatment facilities since they are not typically regulated and water treatment methods at the facilities are not designed to remove them. My research focuses on removing PPCP’s using reactive environmental sorbents like nanocrystalline ferrihydrite. Specifically, I examined the interaction of two widely used PPCP’s (Ibuprofen and Triclosan) with nanocrystalline ferrihydrite of varying particle sizes (<125µm, 125-250 µm, >250 µm). Results thus far show that when Ibuprofen interacts with nanocrystalline ferrihydrite at pH 4.3-4.8; 8.1% was removed when the particle size was less than 125µm; 7.7% was removed when the particle size was 125-250 µm, and 1.3% was removed when the particle size was greater than 250 µm. While for Triclosan 23%, 6.7%, 8% was removed by nanocrystalline ferrihydrite with size <125 µm, 125-250 µm, >250 µm respectively. My presentation will further cover surface properties of nanocrystalline ferrihydrite controlling the sorption of ibuprofen and triclosan.
The rate of lake level fall of the Dead Sea has increased dramatically in the past 35 years to just over 1 m/yr. In response to this rapid lake level decline, the Nahal Darga has incised deeply, exposing the well-dated Holocene strata. During this period of overall regression, several small flood events have been recorded. The Holocene lowstand delta fan of the Nahal Darga at its interface with the Dead Sea is situated within the perfect conditions to understand the signals of subtle lake level rise and fall. Within a sequence, there are systems tracts that record large-scale changes in sea level: the Lowstand Systems Tract, the Transgressive Systems Tract, and the Highstand Systems Tract. All of these systems tracts have certain relationships with each other and have different geometries. The concept of the microsequence is introduced in this study as the components of a sequence within a systems tract, such as the lowstand delta fan of the Nahal Darga. In applying the idea of fractal geometry to sequence stratigraphy, microsequences will mimic the general facies changes and grain size trends of a sequence to show the subtle rises and falls that can occur during an overall period of regression. This study utilizes the thoroughly documented Dead Sea lake level, the most extensively dated Holocene strata in the country of Israel, and a well-exposed wall of an incised valley to test the theory that signals of subtle lake level changes that occurred within the lowstand delta fan of the Nahal Darga may preserve as microsequences.
Plant biomass represents an important component within the biogeochemical cycling of nutrients and contaminants. Transformation of this plant biomass in the environment to organic residuals is dictated primarily by interactions with micro-organisms specifically fungi. My research investigates the effects of fungal colonization of spent coffee grounds as a model for plant biomass to organic matter transformation and how this transformation impacts environmental stability and its ability to bind to contaminants. This presentation will cover; 1) physical and chemical changes in the spent coffee grounds after molding for 0,3,4,5 and 7 months, 2) how these physical changes impact the environmental degradability, and 3) how these physical and chemical changes impact the capacity to bind Gentian violet dye (as a model for organic cations).
Nanoparticles possess unique tunable physical and chemical properties that make them desirable in industrial processes. The tuning of the chemistry and shape of nanoparticles is done to obtain desirable properties that improve bio-imaging, drug delivery, environment remediation, energy storage, and others. A consequence of widespread nanoparticle use is the potential for their intended/unintended release into the environment. In my research, I used flow experiments to investigate the interactions of two widely used nanoparticles (Poly amido amine; PAMAM dendrimer and Graphene Quantum Dots; GQDs) with naturally-occurring iron oxides (ferrihydrite, geothite, and hematite). Specifically, I used two generations of PAMAM dendrimer, PAMAM G4-OH and PAMAM G3.5-COOH, and two variations of Nitrogen-doped GQD (NGQD), untreated NGQD (unt-NGQD) and ozone-treated NGQD (oz-NGQD). At pH7, the sorption of nanoparticles onto the iron oxides followed the trend: PAMAM G3.5-COOH > PAMAM G4-OH > oz-NGQD > unt-NGQD, but comparatively more was sorbed onto freshly produced ferrihydrite (FFH), an amorphous iron oxide compared to Hematite, a well crystallized iron oxide. The trends in the quantities sorbed are influenced by the surface characteristics of iron oxides, and the size and functional groups of the nanoparticles. My presentation will cover, the effects of the chemistry of nanoparticles and the surfaces of iron oxides over a range of environmental significant pH values (pH3-pH11) on the quantity and the rate of the sorption reaction of nanoparticles on iron oxides.
The Barby Formation contains a composite volcanic arc stratigraphic succession up to 8 km thick and lies within the Mesoproterozoic Konkiep terrane of SW Namibia. Previous workers had mapped the Barby Formation as composed primarily of lava flows; however, recent work by TCU geologists suggests that much of the formation is composed of proximal pyroclastic fall deposits erupted from small volcanoes in an environment with low topography and abundant lakes.
This study focuses on investigating the styles of volcanic eruptions and magma compositions in a representative, well-exposed portion of the Barby Formation, as well examining volcanic and intrusive processes occurring the shallow subsurface. Detailed mapping of a well-preserved section of the formation provides cross-sectional views of a complex series of pyroclastic fall deposits and intercalated lacustrine sediments, as well as feeder conduits to volcanic vents. Hypabyssal dikes and sills are common throughout the study area and cross-cut massive bomb-rich units or pierce lacustrine strata and bedded pyroclastic fall deposits. Also present are pyroclastic deposits showing clear intrusive relations with lacustrine sediments, spread out over a horizontal distance of ~600 m and a vertical stratigraphic sequence of ~300 m. Thin section studies of 75 representative samples indicate that the pyroclastic rocks, intrusive pyroclastic rocks, and hypabyssal intrusions have very similar phenocryst populations (altered olivine, augite, and plagioclase), and are likely closely linked petrogenetically.
Organic-mineral interactions at the mineral-water interface are of interest to geoscientists due to their controlling effects upon trajectory and rate of biogeochemical reactions such as electron-transfer, mineral dissolution and precipitation, and degradation/stabilization of organic molecules at this interface. Here, focus is placed upon the sorption and desorption of acetate (CH3COOH) onto a series of synthesized boehmites (amorphous aluminum oxides). The boehmites vary in method procedure which result in differing morphologies and surface behaviors, and are characterized using a series of analytical techniques, including SEM imaging, XRD, and TGA/DSC analysis. Specifically we focus on the influence of the varying amounts of free and structural water present in each boehmite sample when acetate is used to probe the surface heterogeneity of these materials. We investigate the binding energetics and associated mechanics (i.e. bonding types at play here and anion exchange capacity) via flow-adsorption microcalorimetry, a direct and systematic assessment of the energy dynamics in a system.
The southern margin of the North American continent transformed from a passive margin to an
active margin during the Ouachita orogeny. Thick and near–continuous Paleozoic successions in
the Ouachita Mountains provide a unique opportunity to document changes in both
sedimentation and tectonics. In contrast to well-documented Taconic, Acadian, and Alleghenian
orogenic events, limited detrital zircon studies of the Ouachita orogeny and associated
successions have been published, and sediment sources of these deep-water, synorogenic clastics
remain less constrained.
In this study, a total of six outcrop samples (n=617) from the Mississippian Stanley Group and
Lower-Middle Pennsylvanian Jackfork and Johns Valley Groups were collected and processed
for U-Pb detrital zircon geochronologic analyses to depict sediment sources and dispersal
patterns during the Ouachita orogeny. Results show that the age distributions of the
Carboniferous deep-water clastic deposits in the Ouachita Mountains are characterized by major
peaks of the Paleozoic (~350-500 Ma), Grenville (~900-1350 Ma), and Midcontinental GraniteRhyolite (~1350-1500 Ma), minor peaks of Yavapai-Mazatzal (~1600-1800 Ma) and Superior (>
~2500 Ma) provinces. These deep water clastics share great similarities with the Appalachian
sources and are likely derived from similar sources. From the Mississippian Stanley Group to the
Pennsylvanian Jackfork and Johns Valley Groups, the Yavapai-Mazatzal population shows
marked enrichment (up to ~12%), suggesting Precambrian basement uplifts, possibly related to
the Ancestral Rockies to the northwest, might be another potential source. Compilation and
comparison show the Neoproterozoic age population (~550-800 Ma), most likely associated with
the peri-Gondwana terrane to the south, ranges from 3% to 35% within the Mississippian Stanley
Group. The variation indicates that the Stanley Group may have strong but short-lived local
contribution from the Gondwana terrane in addition to the regional Appalachian sources.
Overall, despite its proximal location, these Carboniferous deep-water clastic deposits in the
Ouachita Mountains received limited contribution from the Ouachita orogenic belt itself.
The Dockum Group of the west Texas panhandle and eastern New Mexico is a dryland fluvial-lacustrine system that was deposited during the Triassic Period. Despite being identified in the late 1800’s a definitive depositional model has yet to be established. Most of the research on these strata focuses on the rich abundance of large vertebrate fossils of the Upper Triassic section, and these studies have aided in drawing time equivalency between the Dockum Group and the Chinle Formation directly to the west.
The Chinle Formation has been extensively studied and generalizations of the Dockum climate are largely based on the assumption of similarity because the Dockum is thought to be time equivalent to the Chinle. However, recent work in the Dockum Group has uncovered a dominance of upper flow regime storm sheets and channels in outcrop. These structures and bedforms have yet to be interpreted in the Chinle, yet play an integral part in understanding the climate within the larger Triassic system. Due to both the paleolatitude and the landward positioning of the Dockum Group at the time of deposition, a megamonsoon hypothesis is proposed to explain the occurrence of these upper flow regime structures.
The megamonsoon hypothesis was previously proposed by Judith Parrish to explain anomalous rainfall on the Pangaean continent. It states that the pressure differentials generated by the heating of a landmass the size of Pangea could generate monsoonal storms magnitudes larger than any the modern world has seen. The landward position of the Dockum Group depocenter suggests that only the largest storms would have reached that far inward. Furthermore, the paleolatitude suggests that these storms would have had to be large enough to overcome the prevailing easterly winds.
Although there are upper flow regime structures and bedforms, there are other lithofacies assemblages including: perennial channels with lower flow regime structures, lacustrine sediments, and floodplain deposits. The stacking relationships of these lithofacies assemblages and their interactions with one another come together to tell a more complete story of the deposition of the Dockum Group.
The strata of the Dockum Group are dominated by upper flow regime channels whereas the lower flow regime channels are the exception. The lower flow regime channels are primarily secondary channels located on the floodplain, and they represent low-stage channels from the floodout events. Both upper and lower flow regime channels appear to be sourced from the Ouachita Orogenic Belt to the east, and they deposit into large lakes in the southern extent of the Dockum Group. These lakes are subject to stage fluctuation due to the rapid and cyclic changes in weather within the Triassic system’s climate. The Dockum Group is not prone to well-developed soils except at the base where alternating soil horizons reflect the climatic extremes of intense rainfall followed by dryland conditions. This paleogeographic reconstruction is necessary to better understand the larger depositional history of the Dockum Group which in turn reveals insights regarding the larger Triassic climate regime and the megamonsoon hypothesis.
The increasing amount of excess Greenhouse Gases in the environment threaten the future stability of life on the planet. Carbon dioxide is a GHG that increases acidity in water, contributing to acid rain and uninhabitable aquatic environments. In the atmosphere, carbon dioxide adds to the Greenhouse Effect where excessive heat trapped around the Earth leads to changes in climate that affect the stability of different biospheres. Recently, there has been much interest in what benefits biochars can offer for agricultural and environmental use. Following increasing populations and the introduction of machinery, excess atmospheric carbon prompts for expansion of carbon sinks alongside the reduction of emissions. One can observe a relationship between the use of biochar and increased carbon sequestered in soil. When organic matter is burned in a high-temperature, low-oxygen environment, its molecules become arranged into aromatic, cyclic structures that are not as easily decomposed by microbes as non-charred material. This offers persistency as a benefit in use. Aside from benefiting the environment, it has also been observed that plants may receive benefits in growth. This can be explained as carbon sequestered in the soil has the ability to bond with elements such as sodium or calcium, creating compounds calcium carbonate or sodium carbonate, which can neutralize high soil acidity that inhibits plant growth.
The new world tropics represent an area of unparalleled biodiversity. Unfortunately, it also represents an area of increasing habitat loss and consequently is in dire need of protection and conservation. The TCU San Ramon Tropical Biology Station located on the Caribbean slope of Costa Rica protects 100 hectares of primary and secondary forest and is a unique and ideal location for studying tropical biology. In the summer of 2018, we mapped an updated trail network at the station using a Bad elf sub-meter GNSS receiver in conjunction with Arc Collector. For this project we analyzed the distance each trail traveled through the 3 habitat types found at the station (primary forest, secondary forest, and pasture land), which will be used to aid the sampling efforts of my Master’s thesis project examining how mixed-species foraging flocks utilize the habitat protected by the station.
The Triassic Dockum Group of the western Texas High Plains is studied in depth paleontologically, but until recently lacked a detailed sedimentological evaluation. Recent research of the Dockum Group in Palo Duro Canyon, Texas, provides new interpretations of the complex fluvial lacustrine strata of the comprising formations based on analysis of individual lithofacies. Identified within the lithofacies assemblages are numerous channel belts composed of upper flow regime bedforms. Observed upper flow regime bedforms in outcrop range from upper plane bed, antidunes, breaking antidunes, chutes and pools, and cyclic steps with increasing flow velocity respectively. These channel belts record extreme flow events from repeating massive storms that perpetuated throughout the Texas region of Triassic Pangea. These unique reservoir-quality channels are interpreted to be resultant of a megamonsoonal climate producing massive pulses of rapid flow allowing for the preservation of upper flow regime bedforms. While these channels are identified in outcrop they have not been quantified in distribution, variability in fill, connectivity and formative discharge.
This study aims to test the megamonsoonal hypothesis by quantifying the discharge of these channels and testing if the distribution density and paleodischarge of these channels is consistent with local dominance of megamonsoonal conditions. Upper flow regime structures are rarely preserved in the rock record and extremely difficult to observe directly during natural formation in modern rivers. Most of the equations used to quantify flow conditions for these structures are derived from flume tank experiments. These are applied to the upper flow regime bedforms found in outcrops of the Dockum Group to reconstruct paleohydrology. Current flume tank research reinforces Kennedy’s equations defining relationships between the wavelengths of stable antidune apexes (λ), mean flow depth (hm) and mean flow velocity (U). These equations are modified to account for different upper flow regime structures formed under increasing velocity and discharge identified in outcrop. Bedform distribution, size, and type are variables determined from outcrop measurement. Paleoflow velocities, Froude numbers and relative water depths are determined with an observed margin of error. Scaling relationships and field measurements provide constraints on channel cross sectional area and channel-belt density. This data along with grain size distribution provides tangible numbers for calculating formative discharge. Preliminary results align with data from flume tank experiments and are consistent with major floods produced by substantial storm events verifying the megamonsoonal hypothesis.