Annabelle Foos

Using Conceptests to Assess and Improve Student Conceptual Understanding in Introductory Geoscience Courses

Conceptests are higher-order multiple-choice questions that focus on one key concept of an instructors major learning goals for a lesson. When coupled with student interaction through peer instruction, conceptests represent a rapid method of formative assessment of student understanding, require minimal changes to the instructional environment and introduce many of the recognized principles of effective teaching that enhance student learning. In this study, instructors from several different institutions developed over 300 conceptests for the geosciences. These instructors then used this suite of concept questions in a wide range of classroom settings, including large introductory general education Earth Science courses for non-majors at open enrollment institutions, smaller physical geology classes suitable for majors at private colleges, and in introductory geology laboratory settings. Results of pre- and post-class Geoscience Concept Inventory (GCI) testing and qualitative feedback from students and instructors showed that conceptests increased attendance, improved student satisfaction, and enhanced student achievement. Participating instructors found implementation of conceptests into their classes straightforward and required less than 30 minutes of preparation per class. The conceptest question database is available on-line for geoscience instructors.

Lithic controls on the removal of iron and remediation of acidic mine drainage

Abstract The remediation of streams adversely affected by acidic mine drainage often employs limestone as a neutralization agent. However, metal precipitation on the limestone surface can render it ineffective. This investigation reports preliminary field and laboratory results demonstrating that, in the presence of a mixture of limestone and sandstone, iron preferentially precipitates on the sandstone surface, and iron removal from aqueous solution is greater than with either of the materials alone. First, a river in Tennessee (USA) with preferential iron precipitation was characterized with respect to water quality and lithic surface morphology. Second, a field experiment where lithic samples were placed in an Ohio stream receiving coal mine drainage demonstrated that iron hydroxide preferentially coats quartz-rich lithologies. Finally, laboratory experiments confirmed enhanced iron removal in the presence of mixed lithic surfaces. Based on these results, the use of multiple lithic surfaces, particularly in-stream, has the potential to provide improved methods for the treatment of acidic mine wastes.

Aluminous lateritic soils, Eleuthera, Bahamas; a modern analog to carbonate Paleosols

ABSTRACT Aluminous lateritic soils from Governors Harbour, Eleuthera, Bahamas are described. These soils are forming on eolian ridges under a humid, tropical savanna climate. The parent material is carbonate eolianite plus airborne dust from North Africa. The soils are thin, discontinuous and concentrated in shallow solution pits. They are stony, have a crumb texture and are underlain by pedogenically altered limestones. The solum has a low SiO2/Al2O3 ratio and is composed of boehmite, hydroxy-interlayered clay (HIC), Al-hematite, Al-goethite, calcite and minor quartz. The presence of carbonates in the solum buffers the pH and inhibits gibbsite precipitation, resulting in a high availability of aluminum for incorporation in HIC and iron minerals. The moisture egime of these soils is characterized by frequent wetting and drying due to the high porosity and permeability of the underlying carbonates, and the intermittent nature of the rainfall. Boehmite is the stable Al-phase within cryptovoids where the H2O activities are less than one. The dominant pedogenic features in the altered limestones are voids produced by solution of limestone around plant roots. These voids are subsequently infilled with overlying solum material and cemented with equigranular calcite. Alteration rinds containing micritized carbonate grains, and laminations of micrite and iron-rich clay develop around the voids. Features observed in aluminous lateritic soils are compared to other carbonate soils and paleosols preserved within carbonate sequences.

Crystal size growth in the liquid phase methanol synthesis catalyst

ABSTRACT The phenomenon of crystal growth in the methanol synthesis catalyst has been studied. Crystallite size distributions in the cuo/ZnO/Al2O3 methanol synthesis catalyst have been determined. The effects of temperature, reaction environment and time under reaction conditions have been studied. It is observed that water in the reaction mixture promotes crystal growth.

DETRITAL ORIGIN OF A SEDIMENTARY FILL, LECHUGUILLA CAVE, GUADALUPE MOUNTAINS, NEW MEXICO

Lechuguilla Cave is a hypogene cave formed by oxidation of ascending hydrogen sulfide from the Delaware Basin. A unique sediment deposit with characteristics suggesting derivation from the land surface, some 285 m above, was investigated. At this location, the observed stratigraphy (oldest to youngest) was: bedrock floor (limestone), cave clouds (secondary calcite), calcite-cemented silstone, finely laminated clay, and calcite rafts. Grain-size analysis indicates that the laminated clay deposits are composed of 59-82% clay-size minerals. The major minerals of the clay were determined by X-ray diffraction analysis and consist of interstratified illite-smectite, kaolinite, illite, goethite, and quartz. Scanning electron microscopy observations show that most of the clay deposit is composed of densely packed irregularshaped clay-size flakes. One sample from the top of the deposit was detrital, containing well-rounded, silt-size particles.Surface soils are probably the source of the clay minerals. The small amount of sand- and silt-size particles suggests that detrital particles were transported in suspension. The lack of endellite and alunite is evidence that the clays were emplaced after the sulfuric-acid dissolution stage of cave formation. Fossil evidence also suggests a previously existing link to the surface.

A SINGLE-STAGE, LIQUID-PHASE DIMETHYL ETHER SYNTHESIS PROCESS FROM SYNGAS III. DUAL CATALYST CRYSTAL GROWTH, DEACTIVATION, AND ACTIVITY CONSERVATION STUDIES

ABSTRACT In the liquid phase dimethyl ether (DME) synthesis process, both the methanol synthesis catalyst )composed of CuO, ZnO, and Al2O3) and the methanol dehydration catalyst (composed of gamma-alumina) are slurried in the inert oil phase. Various long-term activity checks were conducted on these dual catalysts to characterize the crystal growth and the thermal aging behavior. X-ray powder diffraction, X-ray fluorescence and elemental intensity compositions, and the crystallite size distributions of the aged catalysts were examined. Based on the current investigation, it was established that the crystal growth and the catalyst deactivation problems in the methanol synthesis catalyst are less severe when it is used along with the methanol dehydration catalyst.

Integration of a class research project into a traditional geochemistry lab course

With careful selection of the research topic, a semester-long, class research project can be integrated into a traditional geochemistry lab course. An aqueous geochemistry project is described, where students make on-site measurements in the field, collect samples and analyze them for major, minor and trace elements. The data are incorporated into exercises on data quality, graphical presentation, ionic strength, ionic activity, carbonate equilibrium, Eh-pH diagrams, and geochemical modeling. The results of each lab are presented to the class the following week and their implications to the research project are discussed. Then the project results are presented as a poster session at a regional scientific meeting. In addition to providing students with a research experience, the class research project reinforces the lecture and weekly laboratory exercises by illustrating the practical application of the geochemical concepts.