Paper presented at the 15th IUGSA Conference, 12-14 November 2012, Bloemfontein

The history of planet formation and evolution is strongly tied to understanding the outcomes of a wide range of impact events, from slow accretionary events to hypervelocity events that melt and vaporize large fractions of the colliding bodies. To better understand impact processes, their effects on planetary evolution, and how to interpret geochemical data, we need to improve our knowledge of the behavior of materials over the entire range of conditions accessed by collisions. Here I present experimental results from gas gun, laser driven, and pulsed power facilities. Together these facilities can access the tremendously wide range of pressure and temperature conditions achieved in natural impact events. This work focuses on the thermodynamics of impacts to better understand the phase transitions that most strongly affect the dynamics and chemical consequences of a collision. I show that the entropy generation during collisions is the most natural means of interpreting the thermodynamic processes that occur during an impact event. For materials with sufficient thermodynamic data at high pressures and temperatures, I present a method for obtaining the entropy generation during an impact. With the knowledge of the entropy, I present new shock-and-release techniques to investigate the liquid-vapor region of the phase diagram. I also show that for materials without sufficient data to calculate the entropy generation during an impact, one can use the shock-and-release techniques described here to determine the entropy in the high pressure shock state. With better equation of state models that are constrained by our experimental data, our confidence in impact models improves dramatically. Using a high fidelity equation of state for \(H_2O\). ice, I derive scaling laws for how much \(H_2O\) ice melts and vaporizes for impacts onto icy bodies. Recognizing that icy bodies are not pure ice, I have performed experiments to show how the impact energy partitions between the disparate phases. Finally, I discuss some of the uncertainties in using the laboratory experiments to directly interpret the effects of impacts in nature. / Earth and Planetary Sciences

The planet crossing asteroids in the inner solar system have strongly chaotic orbits and the distributions of their angular elements (longitude of ascending node, Ω; argument of perihelion, ω; and longitude of perihelion, ϖ) are often regarded as uniform random. In the last decade, the known population of these minor planets has increased by more than a factor of four, providing a sufficiently large dataset for statistical analysis of their distribution. By choosing the observationally complete set of bright objects, we quantified the level of intrinsic non-uniformities of the angular elements for the following dynamical subgroups of Near Earth Objects (NEOs) and Mars Crossing Objects (MCOs): three subgroups of NEOs (Atens, Apollos, and Amors) and two inclination subgroups of MCOs (high and low inclination MCOs, with the boundary at inclination of 15°). Using the methods of angular statistics, we found several statistically significant departures from uniform random angular distributions. We were able to link most of them with the effects of secular planetary perturbations. The distribution of the longitude of ascending node, Ω, for NEOs is slightly enhanced near the ascending node of Jupiter due to the secularly forced inclination vector. Apollos and high inclination MCOs have axial enhancement of ω due to secular dynamics associated with inclination-eccentricity-ω coupling; these enhancements show opposite trends in these two subgroups. The ϖ distributions of Amors and of MCOs are peaked towards the secularly forced eccentricity vector, close to the ϖ value of Jupiter. These non-uniform distributions of the angular elements may affect the asteroidal impact fluxes on the planets. We developed a new approach that accounts for the non-uniform angular elements of planet crossing asteroids to investigate the impact flux and its seasonal variation on the Earth, the Moon, and Mars. The calculation for this study was achieved by generating many clones of the observationally complete subset of bright planet-crossing objects, measuring the Minimum Orbit Intersection Distance (MOID) between the planet and the clones, and making use of the classical formulation of Wetherill (1967) for the collision probability of two objects on independent Keplerian orbits. We developed a novel method to calculate the collision probability for near-tangential encounters; this resolves a singularity in the Wetherill formulation. The impact flux of NEOs on the Earth-Moon system is found to be not affected significantly by the non-uniform distribution of angular elements of NEOs. The impact flux on Mars, however, is found to be reduced by a factor of about 2 compared to the flux that would obtain from the assumption of uniform random distributions of the angular elements of MCOs. Moreover, the impact flux on Mars has a strong seasonal variation, with a peak when the planet is near aphelion. We found that the amplitude of this seasonal variation is a factor of 4-5 times smaller compared to what would be obtained with a uniform random distribution of the angular elements of MCOs. We calculate that the aphelion impact flux on Mars is about three times larger than its perihelion impact flux. We also calculate the current Mars/Moon impact flux ratio as 2.9-5.0 for kilometer size projectiles.

This paper is about modeling the perceived social impacts of three proposed marine protected areas (MPAs), each designed to protect coral reefs. The paper argues that shared perceptions of these impacts have resulted in divergent community-level responses to these MPA proposals. The study is uniquely situated in the Bahamas where the government has approved setting aside 30 No-take MPAs (including three under study here) to protect the coastal marine environment. The paper is based on 572 interviews conducted during eight Weld trips with members of six traditional settlements in the Exuma Islands and Cays in the central Bahamas. Overall, 34% of the census population of these settlements was interviewed at least once. Key Findings are that an MPA can impact in either positive or negative ways (a) community agency by the process of siting, (b) community resilience by eliminating or supporting some components of their traditional adaptations to social and natural environments, and (c) community identity by precluding or protecting customary marine access. MPA impacts to local communities determine whether those communities will support or resist proposed MPAs.

This paper argues for the application of Risk Society (Ulrich Beck & Anthony Giddens) and Social Resilience (Fikret Berkes & Carl Folke) theories in the social impact assessment (SIA) of proposed marine protected areas (MPAs). The former theory is the most cited social theory in Europe and has been found to explain worldwide human responses to proposed projects. The latter theory brings to the SIA of MPAs proven notions from human ecology. This paper is based on an on-going assessment of proposed MPA effects in the Bahamas and the growing literature on MPAs.

This is an assessment of the social and cultural factors that potentially will influence the transfer of Caribbean King Crab or Mithrax mariculture as it has been developed in two West Indian project sites. The projects are located in Nonsuch Bay, Antigua, and Buen Hombre,Dominican Republic. The projects derive from an original proposal entitled "A New Mariculture Project for the Lesser Antilles," which was submitted by the Smithsonian Institution, Marine Systems Laboratory (MSL), to the U.S. Agency for International Development (AID). That project was funded as AID Project No. 598 -065. This anthropological and sociological assessment was contracted by the Smithsonian Institution as specified in P.O. No. ST5080090000 on July 10, 1985.

This presentation was created to supplement the Mithrax Crab culture technical report Caribbean Fishermen Farmers and provide images that can further convey an understanding of the analysis and findings presented in the Antigua portion of the report.

This presentation was created to supplement the Mithrax Crab culture technical report Caribbean Fishermen Farmers and provide images that can further convey an understanding of the analysis and findings presented in the Dominican Republic portion of the report.

American Indian lands and cultural resources have been observed, desired, and then taken by Euroamericans since the "Invasion of America." To know any case of such encroachment is to understand something of the entire history and perhaps the future of Native American - Euroamerican relations. But it is only by comparing cases through time and across space that we see most clearly the patterns that best help us understand this process of encroachment. From our reading of the literature on this subject, especially the outstanding contributions made by Francis Jennings in The Invasion of America (1975) and by Alfred Crosby in The Columbian Exchange (1972), it is clear that certain strategies of competition and domination are regularly utilized by Euroamericans. Because such strategies are deeply rooted in fundamental premises of Euroamerican culture (Hagen 1980:66), we can expect that the strategies are and will continue to be important factors where Native Americans and Euroamericans are competing for resources. Moreover, we believe that much contemporary competition for resources can be viewed as the latest phase in the continuing "Invasion of America" (MacDonald, 1980: 170).

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