Abstract A synthesis of low-temperature thermochronologic results throughout the Laramide foreland illustrates that samples from wellbores in Laramide basins record either (1) detrital Laramide or older cooling ages in the upper ~1 km (0.62 mi) of the wellbore, with younger ages at greater depths as temperatures increase; or (2) Neogene cooling ages. Surface samples from Laramide ranges typically record either Laramide or older cooling ages. It is apparent that for any particular area the complexity of the cooling history, and hence the tectonic history interpreted from the cooling history, increases as the number of studies or the area covered by a study increases. Most Laramide ranges probably experienced a complex tectono-thermal evolution. Deriving a regional timing sequence for the evolution of the Laramide basins and ranges is still elusive, although a compilation of low-temperature thermochronology data from ranges in the Laramide foreland suggests a younging of the ranges to the south and southwest. Studies of subsurface samples from Laramide basins have, in some cases, been integrated with and used to constrain results from basin burial-history modeling. Current exploration for unconventional shale-oil or shale-gas plays in the Rocky Mountains has renewed interest in thermal and burial history modeling as an aid in evaluating thermal maturity and understanding petroleum systems.This paper suggests that low-temperature thermochronometers are underutilized tools that can provide additional constraints to burial-history modeling and source rock evaluation in the Rocky Mountain region.

The incorporation of increasingly multidisciplinary aspects of geoscience curricula into a traditional geology field camp requires compromises. Among these, decisions about projects to reduce or eliminate and course prerequisites are two of the most challenging. Over the past 10 yr, the University of Missouri’s geology field camp has completed a two-stage plan to expand our projects in hydrology and geophysics while maintaining traditional aspects of our course and our standard prerequisites. The first stage added projects in surface and groundwater hydrology, seismic refraction, and surficial mapping during the fifth week of our six-week course, replacing an existing mapping project. The second stage added advanced project options that students can select to complete during the last week of the course. Advanced projects in hydrology and geophysics were added as alternatives to the existing hard-rock structural analysis project that had been the sixth-week project for all students. This staged addition has allowed us to: (1) integrate these projects into a curriculum that maintains a strong emphasis on historical bedrock geology, geologic mapping, and three-dimensional visualization; and (2) accommodate differences in the coursework that students have completed prior to beginning the field camp. Rather than requiring students to have prerequisite courses in hydrogeology or geophysics in order to select these advanced project options, we include sufficient instruction during the fifth and sixth weeks that builds upon previous projects to provide the required background. To set up the context for our expanded hydrology and geophysics projects, this paper briefly describes our traditional field projects and our instructional philosophies. We describe the expanded projects that have been implemented during the fifth and sixth weeks of our course, project objectives, and the ways that these projects reinforce lessons learned during traditional field projects. We present the results of student surveys that have been used to evaluate the success of these efforts, and we discuss the personnel and equipment expenses required.

Continental crust subjected to horizontal contraction in convergent settings deforms in a variety of styles. In many instances, it is useful to consider the deforming crustal sections in terms of crystalline basement rocks underlying incipiently undeformed sedimentary strata. Three deformation styles are commonly found in such settings. The structural style referred to as thin-skinned tectonics encompasses a stack of thrust sheets composed of non- or weakly metamorphic sedimentary rocks. The associated thrust faults usually level off in a mechanically weak décollement horizon along which a substantial amount of displacement occurs in the course of the formation of the fold-and-thrust belt. Thrust faults may also cut down into the crystalline basement and level off a few kilometers beneath the basement-cover interface. The term basement-involved thin-skinned tectonics is proposed to describe this style of continental contraction. This style, too, is characterized by stacks of thrust sheets. In many cases however, such nappe stacks are overprinted by pervasive folding of a crust thermally weakened by magmatic activity or regional burial metamorphism. Thick-skinned tectonics seems less common. This style implies that thrust faults cut across the entire upper crust (and possibly the lower crust). The associated continental contraction is smaller, and the ensuing deformation is characterized by warping of the basement-cover interface. Displacements accumulated in a major basal detachment horizon may connect into mantle by means of a subduction zone. However, under elevated temperatures, pervasive deformation of the hanging wall and footwall rocks may compensate large displacements over relatively short distances. Thin-skinned fold-and-thrust belts are common on both sides of collisional orogens. Noncollisional orogens tend to be more asymmetric.