Born and educated in the Midwest, Carl Buckner Rexroad, Ph.D., (1925–2016) devoted his more than 60 year career investigating Paleozoic conodonts, their taxonomy, and their biostratigraphy. Initially affiliated with the Illinois State Geological Survey, he published his first abstract in 1955 on conodonts from the type Chester (upper Mississippian) in Illinois, followed a year later with a paper on that subject. He subsequently joined the Indiana Geological Survey, Indiana University, as a paleontologist and stratigrapher in 1961 and remained there for the next 54 years. During that time he collaborated with many other specialists and paleontologists from around the world, refining high-resolution interregional and intercontinental correlations of Paleozoic strata. As a teacher and mentor, he supervised university students, often co-authoring papers with them. Many students went on to successful careers themselves as conodont researchers. Rexroad’s legacy in Midwestern biostratigraphy, stratigraphy, and general geology is documented in the nearly 200 papers and abstracts he published, his last being shortly before his death in 2016. He leaves behind a unique reference collection for Silurian biostratigraphy in eastern North America, documenting the care, diligence, and skill that defined his long career.
The 2017 IGS Calendar features an 1878 hand-drawn map of Wyandotte Cave and illustrations of the various structures and formations within the cave. The 21 by 33 inch calendar is printed in full color on heavy poster paper.
Over the past decade, there has been growing recognition of markedly increased seismicity in the U.S. midcontinent. This observation has sparked interest in the possibility that earthquakes may be induced by human activities, specifically in association with wastewater injection. This concern led to numerous localized studies on the topic and in many parts of the central United States—including cases in Oklahoma, Ohio, Colorado, Texas, and Kansas—the occurrence of crustal earthquakes has been positively correlated with wastewater injection. In contrast, seismic events in Indiana have not been directly linked to subsurface injection activities to date. A study did suggest the possibility of small, injection-induced earthquakes near the Indiana-Illinois border, but with little direct evidence to test that claim. Since then, no detailed studies have been published on the subject, nor has there been a systematic collection of the data needed to make an assessment of the potential vulnerability of the state to future induced seismic activity. To assess the possibility that seismicity within the state may be associated with injection practices, we compiled a new database of injection pressure and volume data from 2004 through 2014, as well as recorded earthquakes in Indiana. The injection-well data are from the Indiana Department of Natural Resources, Division of Oil and Gas, while the earthquake data were compiled from the U.S. Nuclear Regulatory Commission and Advanced National Seismic System of the United States Geological Survey.
Using these data, a correlation in space and time between active injection wells and recorded earthquakes was explored. A spatial correlation between earthquakes and injection wells was defined as an earthquake epicenter having occurred within a given lateral distance from a wellhead that was actively injecting at the time of the earthquake. If the mapped earthquake epicenter occurred within 5 km (3.1 miles) of the surface coordinates of the injection wellhead, the correlation was considered high, and if it occurred within 15 km (9.3 miles), the correlation was considered moderate. Earthquakes that occurred outside a 15-km radius from active injection wells were considered to be not correlated. Results of this analysis show four earthquakes having high correlation and two having moderate correlation, all located in an area in southwestern Indiana with a large amount of oil and gas development activity. However, as correlation is not the same as causality, additional research should be undertaken to establish if a causal relationship between injection and seismicity indeed does exist.
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This useful directory lists all the known producers of industrial minerals in the state of Indiana. Commodities listed include cement, clay and shale, crushed stone, dimension limestone, dimension sandstone, gypsum, lime, peat, construction sand and gravel, industrial sand, and slag. Listings are arranged by commodity and county and include the following information, where applicable and available: company name, division, regional company address, telephone number, fax number, website address, e-mail address, mine or plant name, location, address, telephone number, fax number, e-mail address, , quadrangle, congressional land survey location (PLSS), products, geology, notes, Indiana Department of Transportation (INDOT) source numbers, Certified Aggregate Producer Program (CAPP) numbers, and U.S. Dept. of Labor Mine Safety and Health Administration (MSHA) identification numbers.
The related Story Map (igs.indiana.edu/IGSMap/?map=mineralproducers) gives industry information and shows locations of the various mines and plants with zoom capabilities. Clicking on an operation gives contact information. There are preset filters for commodity, mine, company, and county, but other filters are possible. Maps that are generated can be printed and saved. Data can also be downloaded to a CSV file and there are also links to additional sources of information.
Historically, much of the lower Pennsylvanian of Indiana has been considered to be generally nonmarine in origin. The presence of coals, the abundance of plant fossils, the lack of marine fossils, and the influential reports published by Potter and Siever during the 1950s and 1960s regarding sandstone deposition helped set the image of lower Pennsylvanian deposition as predominately fluvial with only minor marine influence. Recent work in Indiana, however, has revealed that many mudstone- dominated intervals were deposited under a tidal influence. In some cases, these marine-influenced intervals overlie coals that have sulfur contents of less than 1 percent.
The major purpose of this study of the conodonts of the Alum Cave Limestone Member of the Dugger Formation in Indiana is to enhance understanding of Desmoinesian (Pennsylvanian) biostratigraphy and paleoenvironments in the Illinois Basin. We collected samples from 25 localities in Gibson, Greene, Knox, Perry, Posey, Sullivan, Vanderburgh, and War-rick Counties in southwestern Indiana. A thin unnamed dark gray to black shale generally, but not uniformly, separates the Alum Cave stratigraphically from the underlying Springfield Coal Member of the Petersburg Formation. Idiognathodus, primarily juveniles, domi-nates the conodont fauna. Hindeodus and Neognathodus are uncommon. Adetognathodus and Idioprioniodus are rare. Notably absent are Diplognathodus, Ubinates, and Gondolella.
Progressive color changes were observed in immature to postmature shale samples from various ages (Silurian to Tertiary) and geographic locations. The thermal alteration index, assessed based on the color of structureless organic matter, along with the spore color index determined on palynomorphs, were compared with vitrinite reflectance values obtained from more than 200 samples. While some correspondence occurs, the resolution of the thermal alteration index and the spore color index is not as precise as changes in vitrinite reflectance, as was expected. The 138 photomicrographs of structureless organic matter and palynomorphs included in this paper can serve as a color reference for the various stages of maturity.
This field trip, led by Lee J. Florea and Samuel S. Frushour, was originally given in September 2012 for the Professional Geologists of Indiana. The field trip focused on caves and karst features in south-central Indiana, with an emphasis on the hydrology of karst aquifers in Monroe and Lawrence Counties.
This report focuses on the deposition of the clay-rich Lagro Formation north of the Wabash-Erie Channel in northeastern Indiana. We present initial depositional models for the Lagro Formation within a segment of the Wabash moraine in northwestern Allen County and two segments of the Salamonie moraine in Huntington County. The models are based on initial descriptions of three rotosonic cores—SC0801, SC0803, and SC0804—that were drilled by the Indiana Geological Survey in September 2008.
Carbonate rocks are a dominant lithology throughout Indiana, and they occur in rock units from upper Cambrian to upper Pennsylvanian in age. Because they are a primary source of energy and mineral resources in the state, they are examined extensively in cores and quarry faces. The description of any rock can, however, vary, depending on the technical skills and background of the examiner and the intended purpose for describing the rock. Carbonates are also complex and highly variable in their grain types and textures. The result is that the same rock could be described in different ways in the field or laboratory depending on the experience and needs of the person describing it. The fact that there are several formal and informal classification schemes used to describe carbonate rocks further complicates this communication problem. Some of these schemes were designed to be used in the field, while others are more suited to examination by petrographic microscope in the laboratory. For these reasons, we created this corebook in the hopes of standardizing terminology; using it, you can make a relatively quick, yet systematic, description of the carbonate rocks typically found in Indiana. This approach and terminology can be applied in varying degrees of detail, but it will still provide a fast, accurate, and consistent method of describing hand samples of carbonate rock by persons having diverse technical backgrounds, including geologists, engineers, drillers, miners, regulators, archivists, and educators.
Limestone Campus Walking tour
Indiana's Dimension Stone Legacy presentation
Old State House Quarry tour at McCormick's Creek State Park
Curiosity Fair at Conner Prairie
Jun 10 - 11
Geology of Salem Limestone colloquium
Limestone Campus Walking tour
Mining in Society scouting workshop
Jun 24 8:00A - 4:00P
Quake Cottage at New Harmony State Historic Site
Jul 07 - 09
New Harmony Garden Club presentation
Jul 08 9:00A - 10:00A
Indiana Rocks & Fossils Program at Ellettsville Public Library
Jul 13 11:00A - 12:00P
Indiana Rocks & Fossils Program at Bloomington Public Library
Jul 13 2:30P - 3:30P
Lilly Summer Science Camp
Jul 17 10:00A - 2:00P
Eagle Creek Park Master Naturalist
Aug 03 6:00P - 9:00P
Quake Cottage at Falls of the Ohio State Park
Sep 09 10:00A - 4:00P
Quake Cottage at Kentucky Geological Survey
Oct 11 6:00P - 8:00P