ABSTRACT Suborbital analysis (SA) is presented here as the study of ballistics around a spherical planet. SA is the subset of orbital mechanics where the elliptic trajectory intersects Earth’s surface at launch point A and fall point B , known as the A -to- B suborbital problem, both launch and fall points being vector variables. Spreadsheet tools are offered for solution to this problem, based on the preferred simplified two-body model. Although simplistic in top-level description, this problem places essential reliance on reference frame transformations. Launch conditions in the local frame of point A and rotating with Earth require conversion to the nonrotating frame for correct trajectory definition, with the reverse process required for complete solution. This application of dynamics requires diligent accounting to avoid invalid results. Historic examples are provided that lack the requisite treatment, with the appropriate set of solution equations also included. Complementary spreadsheet tools SASolver and Helix solve the A -to- B problem for loft duration from minimum through 26 h. All provided spreadsheet workbook files contain the novel three-dimensional latitude and longitude plotter GlobePlot. A global ejecta pattern data set calculated using SASolver is presented. As visualized through GlobePlot, SASolver and Helix provide solutions to different forms of the A -to- B problem, in an effort to avoid errors similar to the historic misstep examples offered as a supplement. Operating guidelines and limitations of the tools are presented along with diagrams from each step. The goal is to enable mechanically valid interdisciplinary terrestrial ejecta research through novel perspective and quality graphical tools, so others may succeed where 1960s National Aeronautics and Space Administration researchers did not.

Extended Abstract Although the final stage of formation of the Gulf of Mexico is fairly well constrained, earlier evolution is still debated. The final stage was rotation of Yucatan about a Florida Straits Euler pole that created most of the observed oceanic crust ( Pindell and Dewey, 1982 ). From observations of salt overlying seaward-dipping reflectors (diagnostic of volcanism during the rift to drift transition) in the northeast Gulf of Mexico, we suggest that salt was deposited at the onset of sea floor spreading, which coincides with initiation of the rotational motion of Yucatan. It is important to understand Yucatan motion that preceded this rotation because delineating any presalt play that might exist would be dependent on understanding of depositional systems developed during this early motion of Yucatan. Very little is known about the nature of presalt deposition in the northern Gulf of Mexico. Salt is Callovian or earliest Oxfordian in age, and the next oldest rocks known from the northern Gulf of Mexico are Late Triassic red beds found in what are generally regarded as proximal grabens formed during early rifting. This gap in knowledge, what we refer to as the “50 million year gap,” can potentially be bridged by incorporating analogs with known systems in Mexico and northern South America. There are uncertainties here, however, mostly based on how Mexico and northern South America are palinspastically restored and the fact that these rocks are in a proximal location. In particular, we note that there was a long-lived continental margin arc in Mexico that lasted from the Permian through the Middle Jurassic ( Barboza-Gudino et al. , 2012 ). A lot of the rocks of this age seen in Mexico that are linked to Gulf of Mexico rifting are in fact associated with this arc. In this presentation, we will review reconstructions of the region and develop a tectonic model that forms the basis for further understanding of rifting in the Gulf of Mexico.

Seismic anisotropy is an efficient way to investigate the deformation field within the upper mantle. In the framework of rigid tectonic plates, we make use of recent tomographic models of azimuthal anisotropy to derive the best rotation pole of the Pacific plate in the uppermost 200 km of the mantle. It is found to be in good agreement with current plate motion (NUVEL1, HS3, and NNR). However, when dividing the Pacific plate into two subplates separated by what we refer to as the megagash, an east-west low-velocity and low-anisotropy band extending across the Pacific plate from Samoa-Tonga to the Easter–Juan Fernández Islands, the rotation pole of northern Pacific is still in agreement with current plate motion but not the rotation pole of the southern part of the Pacific, far away from the “classical” rotation pole of the Pacific plate. This result suggests a differential motion between the North and South Pacific and an ongoing reorganization of plates in the Pacific Ocean. The megagash might be a future plate boundary between the North and South Pacific plates, associated with the intense volcanism along this band.

Lithospheric foundering or delamination has been long recognized as an important process in the formation of the Andes, but the scale, timing, and surface uplift consequences remain controversial. We use recently completed ambient noise tomography and finite-frequency P-wave tomography results and other geologic and geophysical information to identify two ~200-km-diameter regions of piecemeal delamination in the Puna region between 21°S and 27°S. One location in the northern Puna Plateau is centered under the 11–1 Ma large-volume silicic Altiplano-Puna volcanic center, and the other in the southern Puna Plateau is centered approximately between the Arizaro Basin and 6–2 Ma Cerro Galan volcanic field. The foundering in the northern location has progressed to the point where the main thermal anomaly resides in the middle and upper crust, and the surface volcanic flare-up and mantle thermal anomalies are both in a waning stage. In the southern location, the main thermal anomaly is still in its waxing stage in the lower crust and upper mantle, and the foundering mantle material is imaged in the mantle wedge. The differing patterns of back-arc volcanism in the two foundering centers suggest different styles and timing of delamination, with the foundering process coming to completion earlier in the north than in the south. Based on plate-motion reconstructions, the NE-SW–aligned Juan Fernandez Ridge swept southward through this area starting about ca. 14 Ma in the north and ca. 10 Ma in the south. Although we do not think the passage of the Juan Fernandez Ridge initiated foundering, it played an important role in facilitating delamination by increasing interplate coupling, and weakening and perhaps hydrating the upper plate, and its passage allowed the delaminated material to sink into the expanding space of the mantle wedge. Another important factor in this evolution is the upper-plate lithospheric strength variations inherited from the different geologic basements underlying the northern and southern Puna regions. As the larger-scale delamination progressed, leaving behind thin lithosphere and a mantle wedge with a mixture of continental lithospheric fragments and hot asthenosphere, smaller secondary Rayleigh-Taylor instabilities occurred beneath the southern Puna Plateau, influencing basin development, and subsequent melting of this “drip” material was the source of the ensuing low-volume mafic volcanism.

During the last ~100 years, tectonic geodesy has evolved from sparse field-based measurements of crustal deformation to the use of space geodetic techniques involving observations of satellites and from satellites orbiting Earth, which reveal a variety of tectonic processes acting over a wide range of spatial and temporal scales. Early terrestrial measurements using triangulation and leveling techniques characterized large displacements associated with great earthquakes and led to the recognition of the fundamental mechanics of seismic faulting and the earthquake cycle. More precise measurements using ground-based laser ranging allowed for the characterization and modeling of interseismic strain buildup and determination of slip rates on major faults. Continuous and highly accurate point measurements of strain, tilt, and fault creep have captured intriguing deformation transients associated with slow slip events on active faults. The greatly improved precision, spatial and temporal resolution, global coverage, and relatively low cost of space geodetic measurements led to a revolution in crustal deformation measurements of a range of tectonic processes. Very Long Baseline Interferometry, the Global Positioning System, Interferometric Synthetic Aperture Radar, and space-based image geodesy complement each other to comprehensively capture tectonics in action at scales ranging from meters to global and seconds to decades. Space geodetic measurements allow for the precise measurement of global plate motions, the determination of strain rate fields and fault slip rates in distributed plate-boundary deformation zones, and characterization of subtle intra-plate deformation. These measurements provide increasingly important constraints for earthquake hazard studies. Space geodesy also allows for the recognition and detailed model exploration of a number of transient deformation processes during the post-earthquake deformation phase of the earthquake cycle. Measurements of postseismic deformation transients provide important insights into the mechanisms, rheological properties, and dynamics of crustal deformation. Increasingly, seafloor geodetic measurements provide information about deformation on the 70% of the Earth's surface that were previously inaccessible. Future improvements of modern geodetic techniques promise to further illuminate details of crustal deformation at all spatial and temporal scales, leading to an improved understanding of the dynamics of active tectonics.