Natural, Experimental, and Educational Explorations of the Interiors of Terrestrial Planetary Bodies

Planetary interiors are enigmatic, inaccessible, and vital to the processes that have formed the rocks we see on the surface of bodies in the inner Solar System today. Based on geophysical explorations of the Moon and Earth, along with information gleaned from rocks at the surface today, there is understanding of the basic structure and processes at depth. Using a combination of natural samples and experimental studies, we attempt to learn more about the physical conditions beneath the surface, and their effect on material properties and tectonics processes in the mantle. On Earth, mid-ocean ridge processes have long been debated, and there has been little consensus on the magmatic plumbing and extent of ocean-water circulation at depth, leaving a debate between two end-member models of crustal accretion. Using geothermometry and geospedometry of lower-crustal and upper-mantle rocks from a paleo-ridge in the Samail Ophiolte, alongside a similar suite of rocks from the actively spreading East Pacific Rise at Hess Deep, we compare the thermal structure of the crust-mantle transition zone and implications for the on-axis processes that form much of the Earth’s crust. Past work has constrained the crystallization sequence of the moon through time and determined one of the last layers to crystallize was highly dense, containing a significant fraction of the mineral ilmenite, and initially formed above the less-dense mantle cumulate pile, composed mainly of mafic minerals. To study the possible interactions of these two layers due to the density instability, I completed shear deformation experiments on ilmenite and olivine aggregates, in equilibrium, to compare to aggregate flow laws proposed for phase mixing and determine the system rheology. To introduce high school students in East Tennessee to the concept of mantle materials and conditions versus crustal materials and their formation conditions, I have created an activity and corresponding lesson plan for use in secondary school Chemistry classrooms. This activity combines phase diagrams, physical models of chemical bonds, and a comparison of two native minerals with the same chemical formula to help students think about the effects of pressure and temperature on Earth materials

Teaching Theory, Research, and Service in the Cemetery: A Service-Learning Project

This service-learning project is designed to involve students in a cemetery-research preservation project. It commences first in the classroom where students are introduced to anthropological theories and methodological concepts. After the learning process, students take an ethnographic field trip to a historical cemetery where they are instructed to gather data from tombstones of families and individuals that pertains to lessons learned in the classroom, such as social identity and symbols. The research-service component also requires them to record observed environmental problems or preservation needs via notebooks, digital camera, cell phones or other electronic devices. As an outgrowth of this project since 2006, students have adopted a burial site for preservation and beautification; participated in identifying deteriorating monuments, tombstones and markers, and secured temporary markers for the unknown. Finally, they have used the data for research presentations at professional conferences, academic and community service programs

Teaching Theory, Research, and Service in the Cemetery: A Service-Learning Project

This service-learning project is designed to involve students in a cemetery-research preservation project. It commences first in the classroom where students are introduced to anthropological theories and methodological concepts. After the learning process, students take an ethnographic field trip to a historical cemetery where they are instructed to gather data from tombstones of families and individuals that pertains to lessons learned in the classroom, such as social identity and symbols. The research-service component also requires them to record observed environmental problems or preservation needs via notebooks, digital camera, cell phones or other electronic devices. As an outgrowth of this project since 2006, students have adopted a burial site for preservation and beautification; participated in identifying deteriorating monuments, tombstones and markers, and secured temporary markers for the unknown. Finally, they have used the data for research presentations at professional conferences, academic and community service programs

CHRONOLOGICAL AND GEOCHEMICAL FRAMEWORK FOR OVERLAPPING MAGMATISM, DUCTILE DEFORMATION, AND HYDROTHERMAL CIRCULATION IN THE CORDILLERA BLANCA, PERU

The Cordillera Blanca in central Peru, is an example of synconvergent extension following increased exhumation, enhanced weathering and erosion, and development of high, potentially unstable, terrane. The western edge of the range is being exhumed along a normal fault extending parallel to the subduction zone. Normal faulting has exposed a young ductile shear zone capping coeval granodiorite. Preservation of a mid-crustal detachment along an active structure provides an opportunity to explore the causes of trench-parallel synconvergent extension. In chapter one, I report δ2H [hydrogen isotope] values from micas within the detachment-associated Cordillera Blanca shear zone to proxy paleoelevation and explore the role of meteoric fluid infiltration and topographic evolution in the formation of this fault system. In chapter two, I use existing δ2H [hydrogen isotope] and δ18O [delta 18-O] values from surface and thermal waters in the Upper Rio Santa River catchment to explore the most appropriate stable isotope-based lapse rate for reconstruction of historic elevation in the Cordillera Blanca. In chapter three, I deploy zircon 206Pb*/238U [uranium lead] ages and trace and rare earth element chemistry from granites in the Cordillera Blanca and Cordillera Huayhuash to explore magmatism during slab shallowing and connections between timing of igneous activity, fluctuations in crustal thickness, and initiation of the Cordillera Blanca detachment. In chapter four, I apply 40Ar/39Ar [forty-argon-thirty-nine argon] thermochronology of micas and feldspar from across the range to constrain the timing of exhumation and cooling of the Cordillera Blanca shear zone and batholith. These approaches dictate that magmatism progressed from south to north across the central Peruvian Andes during a period of crustal thickening and thinning. Magmatism aids localized weakness in the upper and middle crust. This weakening is associated with intrusion of the youngest magmatic rocks in the region, which aid local stress switching and extension. Meteoric water that is introduced during early stages of detachment development was derived from high elevations that were 500 – 700 m below the modern mean elevation. The interplay of magmatism and meteoric water infiltration result in a period of rapid, fault-driven exhumation that migrated south to north between 5.2 to 3.7 Ma

Data Annex to Thermal history of lithosphere formed beneath fast spreading ridges: Constraints from the Mantle Transition Zone of the East Pacific Rise at Hess Deep and Oman Drilling Project, Wadi Zeeb, Samail ophiolite

The data archive included in this repository is a single table file containing major and trace element data collected by electron microprobe and laser ablation inductively coupled mass spectrometric analysis of gabbros and peridotites from the East Pacific Rise at Hess Deep, and the Samail ophiolite, Oman. The samples were collected by IODP Expedition 345 and ODP Leg 147, and the CM1 and CM2 drillsites of the Oman Drilling Project, at Wadi Zeeb, Wadi Tayin Massif. The data archive also includes replicate analysis trace element data for reference material BCR-2G. The data included in this repository were used to calculate temperatures and cooling rates of rocks in the lower crust and upper mantle using relevant geothermometers and geospeedometers. The file contains tabs which are ordered by mineral name with major elements, followed by separate tabs for trace elements in clinopyroxene, orthopyroxene and plagioclase. Sample names follow an Expedition/Leg_Hole_CoreNumberCoreSegment_Interval naming scheme, with samples beginning in 345 cored/collected during IODP Expedition 345, samples beginning in 147 cored/collected during ODP Leg 147, and samples beginning with 5057 cored during Phase 2 of the Oman Drilling Project, ICDP Expedition 5057.THIS DATASET IS ARCHIVED AT DANS/EASY, BUT NOT ACCESSIBLE HERE. TO VIEW A LIST OF FILES AND ACCESS THE FILES IN THIS DATASET CLICK ON THE DOI-LINK ABOV

Navigation Concepts for the James Webb Space Telescope

This paper evaluates the performance that can be achieved using candidate ground and onboard navigation approaches for operation of the James Webb Space Telescope, which will be in an orbit about the Sun-Earth L2 libration point. The ground navigation approach processes standard range and Doppler measurements from the Deep Space Network The onboard navigation approach processes celestial object measurements and/or ground-to- spacecraft Doppler measurements to autonomously estimate the spacecraft s position and velocity and Doppler reference frequency. Particular attention is given to assessing the absolute position and velocity accuracy that can be achieved in the presence of the frequent spacecraft reorientations and momentum unloads planned for this mission. The ground navigation approach provides stable navigation solutions using a tracking schedule of one 30-minute contact per day. The onboard navigation approach that uses only optical quality celestial object measurements provides stable autonomous navigation solutions. This study indicates that unmodeled changes in the solar radiation pressure cross-sectional area and modeled momentum unload velocity changes are the major error sources. These errors can be mitigated by modeling these changes, by estimating corrections to compensate for the changes, or by including acceleration measurements