The Eocene-Oligocene transition (EOT), ~34Ma, marks a tipping point in the long-term Cenozoic greenhouse to icehouse climate transition. Paleorecords reveal stepwise rapid cooling and ice growth across the EOT tightly coupled to a transient benthic δC excursion and a major and permanent deepening of the carbonate compensation depth (CCD). Based on biogeochemical box modeling, Merico et al. (200...

The Rb/Sr ratios of lake sediments have been suggested as indicators of weathering intensity by increasing work. However, the geochemistry of Rb/Sr ratios of lake sediments is variable between different lakes. In this study, we investigated the spatial and temporal patterns of Rb/Sr ratios, as well as those of other major elements in surface sediments of Lake Qinghai. We find that the spatial p...

Introduction and Motivation: Mineral grains on the surfaces of airless planetary bodies like the Moon are subjected to continuous radiation processing from solar energetic ions and also experience micrometeorite impact events. Together these processes alter the morphology, chemistry, and microstructure of surface particles and are collectively known as space weathering [1]. The optical properti...

Residual fuel oil spilled into the sea from the Eshkol power station on 8 February, 1998 contaminated about 9 km of the foreshore north of the Ashdod harbour. A study of the aliphatic, polycyclic alkane and polyaromatic hydrocarbon (PAH) composition of the spilled oil shows rapid weathering in the early stages followed by gradual slowdown after about three months. Weathering of isoprenoids and ...

STATEMENT OF PROBLEM The clinical life of a maxillofacial prosthesis averages about 6 months, before it needs to be refabricated. Degradation of the color and physical properties of the prosthesis are the principle reasons for replacement. PURPOSE This second part of a 3-part in vitro investigation evaluated the change in physical properties of popular colorant-elastomer combinations as a res...

An experimental study to define a practical methodology that will serve to assess the burning of crude oils on a water sub-layer by means of a bench scale procedure is presented. A modified ASTM-E1321 (LIFT) is combined with flash point measurements to extract fuel properties by means of an existing theoretical formulation. The fuel and water layers are treated as a thermally thick material wit...

24 25 Chemical weathering and mechanical erosion are first order processes of long-term 26 tropical morphogenesis, which is still poorly deciphered for lack of time constraints. We 27 address this issue by laser-probe 39 Ar40 Ar dating of generations of cryptomelane [K128 2Mn8O16, nH2O] from the manganese ore deposit of Tambao in northern Burkina Faso. This 29 Mn deposit results from the superg...

SIMULATION OF 3D MODEL, SHAPE, AND APPEARANCE AGING BY PHYSICAL, CHEMICAL, BIOLOGICAL, ENVIRONMENTAL, AND WEATHERING EFFECTS Joseph T. Kider Jr. Supervisor : Norman I. Badler Physical, chemical, biological, environmental, and weathering effects produce a range of 3D model, shape, and appearance changes. Time introduces an assortment of aging, weathering, and decay processes such as dust, mold, ...