Petrology of the Massillon Sandstone at the Type Locality

Author Institution: Geologist, Indiana Geological Survey, Bloomington, Indian

Outcrop Features of the Mansfield Formation in Southwestern Indiana

Indiana Geological Survey Report of Progress 26The Mansfield Formation of early Pennsylvanian age crops out in an area of approximately 1,700 square miles in southwestern Indiana. Three-fifths of the formation consists of sandstone; most of the remainder is finer clastic rocks. Limestone, chert, coal, and iron ore make up approximately 2 percent of the formation. Many similar rock types are found among the several formations upon which the Mansfield unconformably rests, but the assignment of questionable outcrops either to the Mansfield Formation or to an older formation can usually be accomplished with some confidence, because many outcrops contain either diagnostic rock types or indicative rock features. The various rocks of the Mansfield Formation are, for the most part, arranged in a crudely cyclic pattern. The several cyclic units of a region tend to be similar in makeup and different from those of adjacent regions. Three lithofacies that reflect these areal variations can be recognized and are here named: the Shoals Lithofacies is characterized by cross-stratified sandstones, the Bloomfield Lithofacies by gray shales, and the Cannelton Lithofacies by mudstones and thick clays. The distribution of these lithofacies suggests that these rocks were deposited at or near the shoreline, that there was a fairly large delta in the southern part of the outcrop area, and that this delta was an important factor controlling the sedimentary pattern during early Pennsylvanian time.Indiana Department of Conservatio

Rocks Associated With the Mississippian-Pennsylvanian Unconformity in Southwestern Indiana

The purpose of this field conference is to acquaint participants with strata that are associated with the Mississippian-Pennsylvanian unconformity in southwestern Indiana. Criteria which aid in distinguishing between Mansfield strata of Pottsville (early Pennsylvanian) age and classic formations of Chester (late Mississippian) age will receive considerable attention in discussions at evening meetings and on the outcrop. Inspection of limestone and sandstone quarries will afford an insight into the economic products of Chester and Mansfield rocks

Molecular biogeography and host relations of a parasitoid fly

© 2019 The Authors. Ecology and Evolution published by John Wiley & Sons Ltd. Successful geographic range expansion by parasites and parasitoids may also require host range expansion. Thus, the evolutionary advantages of host specialization may trade off against the ability to exploit new host species encountered in new geographic regions. Here, we use molecular techniques and confirmed host records to examine biogeography, population divergence, and host flexibility of the parasitoid fly, Ormia ochracea (Bigot). Gravid females of this fly find their cricket hosts acoustically by eavesdropping on male cricket calling songs; these songs vary greatly among the known host species of crickets. Using both nuclear and mitochondrial genetic markers, we (a) describe the geographical distribution and subdivision of genetic variation in O. ochracea from across the continental United States, the Mexican states of Sonora and Oaxaca, and populations introduced to Hawaii; (b) demonstrate that the distribution of genetic variation among fly populations is consistent with a single widespread species with regional host specialization, rather than locally differentiated cryptic species; (c) identify the more-probable source populations for the flies introduced to the Hawaiian islands; (d) examine genetic variation and substructure within Hawaii; (e) show that among-population geographic, genetic, and host song distances are all correlated; and (f) discuss specialization and lability in host-finding behavior in light of the diversity of cricket songs serving as host cues in different geographically separate populations

Rocks Associated with the Mississippian-Pennsylvanian Unconformity in Southwestern Indiana

Indiana Geological Survey Guidebook 9The purpose of this field conference is to acquaint participants with strata that are associated with the Mississippian-Pennsylvanian boundary in southwestern Indiana. Criteria which aid in distinguishing between Mansfield strata of Pottsville (early Pennsylvanian) age and clastic formations of Chester (late Mississippian) age will receive considerable attention in discussions at evening meetings and on the outcrop. Inspection of limestone and sandstone quarries will afford an insight into the economic products of Chester and Mansfield rocks. Participants may collect fossils at many of the stops.Indiana Geological Survey; Indiana Department of Conservation Department of Geology, Indiana Universit

Line-profile tomography of exoplanet transits I: The Doppler shadow of HD 189733b

We present a direct method for isolating the component of the starlight blocked by a planet as it transits its host star, and apply it to spectra of the bright transiting planet HD 189733b. We model the global shape of the stellar cross-correlation function as the convolution of a limb-darkened rotation profile and a gaussian representing the Doppler core of the average photospheric line profile. The light blocked by the planet during the transit is a gaussian of the same intrinsic width, whose trajectory across the line profile yields a precise measure of the misalignment angle and an independent measure of v sin I. We show that even when v sin I is less than the width of the intrinsic line profile, the travelling Doppler "shadow" cast by the planet creates an identifiable distortion in the line profiles which is amenable to direct modelling. Direct measurement of the trajectory of the missing starlight yields self-consistent measures of the projected stellar rotation rate, the intrinsic width of the mean local photospheric line profile, the projected spin-orbit misalignment angle, and the system's centre-of-mass velocity. Combined with the photometric rotation period, the results give a geometrical measure of the stellar radius which agrees closely with values obtained from high-precision transit photometry if a small amount of differential rotation is present in the stellar photosphere.Comment: 8 pages, 5 figures, 2 tables; accepted by MNRA