Essex county social workers : their attitudes toward women.

Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1976 .M53. Source: Masters Abstracts International, Volume: 40-07, page: . Thesis (M.S.W.)--University of Windsor (Canada), 1976

Evolution of CO2 and H2O on Mars: A cold Early History?

The martian climate has long been thought to have evolved substantially through history from a warm and wet period to the current cold and dry conditions on the martian surface. This view has been challenged based primarily on evidence that the early Sun had a substantially reduced luminosity and that a greenhouse atmosphere would be difficult to sustain on Mars for long periods of time. In addition, the evidence for a warm, wet period of martian history is far from conclusive with many of the salient features capable of being explained by an early cold climate. An important test of the warm, wet early Mars hypothesis is the abundance of carbonates in the crust [1]. Recent high precision isotopic measurements of the martian atmosphere and discoveries of carbonates on the martian surface provide new constraints on the evolution of the martian atmosphere. This work seeks to apply these constraints to test the feasibility of the cold early scenari

Formation of Jarosite in the Marwrth Vallis Region of Mars by Weathering Within Paleo-Ice Deposits

Here we report new detections of jarosite in the Mawrth Vallis region of Mars. These newly recognized deposits expand the known occurrences of sulfates [1-2] in the region and further expand the already considerable geologic-mineralogic diversity of the Mawrth Vallis area [3-6]. The occurrence of sulfates such as jarosite in geologic contact with thick deposits of phyllosilicates in the Mawrth Vallis area is a relatively rare case on Mars where the enigmatic transition from an early phyllosilicateforming era to a younger sulfate-forming era [7] can be explored. We propose an ice-weathering model which can potentially explain the formation of jarosite-silicakaolinite within acidic ice deposits

Exploring the Cloud Icy Early Mars Hypothesis Through Geochemistry and Mineralogy

While ancient fluvial channels have long been considered strong evidence for early surface water on Mars, many aspects of the fluvial morphology and occurrence suggest that they formed in relatively water limited conditions (com-pared to Earth) and that climatic excursions allowing for surface water might have been short-lived. Updated results mapping valley networks at higher resolution have changed this paradigm, showing that channels are much more abundant and wide-spread, and of higher order than was previously recognized, suggesting that Mars had a dense enough atmosphere and warm enough climate to allow channel formation up to 3.6-3.8 Ga. This revised view of the ancient martian climate might be broadly consistent with a climate history of Mars devised from infrared remote sensing of surface minerals, suggesting that widespread clay minerals formed in the Noachian, giving way to a sulfur-dominated surface weathering system by approx. 3.7 Ga

Experimental Evidence for Weathering and Martian Sulfate Formation Under Extremely Cold Weather-Limited Environments

High resolution photography and spectroscopy of the martian surface (MOC, HiRISE) from orbit has revolutionized our view of Mars with one of the most important discoveries being wide-spread layered sedimentary deposits associated with sulfate minerals across the low to mid latitude regions of Mars [1, 2]. The mechanism for sulfate formation on Mars has been frequently attributed to playa-like evaporative environments under prolonged warm conditions [3]. However, there are several problems with the presence of prolonged surface temperatures on Mars above 273 K during the Noachian including the faint young Sun [4] and the presence of suitable greenhouse gases [5]. The geomorphic evidence for early warm conditions may instead be explained by periodic episodes of warming rather than long term prolonged warm temperatures [6]. An alternate view of the ancient martian climate contends that prolonged warm temperatures were never present and that the atmosphere and climate has been similar to modern conditions throughout most of its history [6]. This view is more consistent with the climate models, but has had a difficult time explaining the sedimentary history of Mars and in particular the presence of sulfate minerals. We suggest here that mixtures of atmospheric aerosols, ice, and dust have the potential for creating small films of cryo-concentrated acidic solutions that may represent an important unexamined environment for understanding weathering processes on Mars [7, 8]. This study seeks to test whether sulfate formation may be possible at temperatures well below 0 C in water limited environments removing the need for prolonged warm periods to form sulfates on early Mars

Olivine Weathering aud Sulfate Formation Under Cryogenic Conditions

High resolution photography and spectroscopy of the martian surface (MOC, HiRISE) from orbit has revolutionized our view of Mars with one of the most important discoveries being widespread layered sedimentary deposits associated with sulfate minerals across the low to mid latitude regions of Mars. The mechanism for sulfate formation on Mars has been frequently attributed to playalike evaporative environments under prolonged warm conditions. An alternate view of the ancient martian climate contends that prolonged warm temperatures were never present and that the atmosphere and climate has been similar to modern conditions throughout most of its history. This view has had a difficult time explaining the sedimentary history of Mars and in particular the presence of sulfate minerals which seemingly need more water. We suggest here that mixtures of atmospheric aerosols, ice, and dust have the potential for creating small films of cryoconcentrated acidic solutions that may represent an important unexamined environment for understanding weathering processes on Mars. This study seeks to test whether sulfate formation may be possible at temperatures well below 0degC in water limited environments removing the need for prolonged warm periods to form sulfates on early Mars. To test this idea we performed laboratory experiments to simulate weathering of mafic minerals under Marslike conditions. The weathering rates measured in this study suggest that fine grained olivine on Mars would weather into sulfate minerals in short time periods if they are exposed to H2SO4 aerosols at temperatures at or above 40degC. In this system, the strength of the acidic solution is maximized through eutectic freezing in an environment where the silicate minerals are extremely fine grained and have high surface areas. This provides an ideal environment despite the very low temperatures. On Mars the presence of large deposits of mixed ice and dust is undisputed. The presence of substantial sulfurrich volcanism, and sulfurrich surface deposits also makes it very likely that sulfate aerosols have also been an important component of the martian atmosphere. Thus mixtures of ice, dust, and sulfate aerosols are likely to have been common on the martian surface. Given the fact that it is not difficult to achieve surface temperatures above 40degC on Mars throughout its history, it seems likely that sulfate formation on Mars is controlled by the availability of sulfate aerosols and not by the martian climate. The current polar regions of Mars and Earth provide interesting analogs. Large regions of sulfaterich material have been detected on and around the modern north polar region of Mars. The prevalence of icedust mixtures in this region and the existence of sulfates within the ice cap itself are strong evidence for the origin of the sulfates from inside the ice deposits. In addition sulfates have been found in ice deposits in Greenland and Mount Fuji on Earth that have been attributed to forming within the ice deposit. These sulfates can form either through interaction with dust particles in the atmosphere or through weathering inside the ice itself

Sedimentary Mounds on Mars: Tracing Present-day Formation Processes into the Past

High resolution photography and spectroscopy of the martian surface (MOC, HiRISE) from orbit has revolutionized our view of Mars with one and revealed spectacular views of finely layered sedimentary materials throughout the globe [1]. Some of these sedimentary deposits are 'mound' shaped and lie inside of craters (Fig 1). Crater mound deposits are found throughout the equatorial region, as well as ice-rich deposits found in craters in the north and south polar region [2-4]. Despite their wide geographical extent and varying volatile content, the 'mound' deposits have a large number of geomorphic and structural similarities that suggest they formed via equivalent processes. Thus, modern depositional processes of ice and dust can serve as an invaluable analog for interpreting the genesis of ancient sedimentary mound deposits