Cutting Edge > Structural Geology > 2014 Structure and Tectonics Forum > Session topics, workshops, & field trips

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Session topics, workshops, and field trips

The general schedule provides a chron listing of the general Forum program.

Technical sessions

The Forum will have poster and oral presentations in the following topical sessions. The abstract deadline is May 2, and you must submit your abstract on line.

The technical session chairs will select a small number of abstracts for oral presentations among those submitted to sessions 1-6 above. All other submissions will be presented as posters, including all those submitted under the general topic of research in structural geology, geophysics, and tectonics.

Special session for grad students and post docs: preparing for an academic career in the geosciences

Field trips

Optional, taking place before and after the Forum (June 14, 15, 19, and 20). You must register for these when you register for the Forum (opens in a new window).

The Homestake shear zone hosts the largest mapped pseudotachylyte system in the world and uniquely preserves details of earthquake rupture at the fault system scale. It incorporates a 25-kilometer-long, partitioned system of strike-slip to oblique dip-slip pseudotachylytes and dip-slip mylonites. The shear zone originated as a high-temperature structure during continental assembly at ~1.7 Ga and was reactivated as a subvertical, transpressional system at ~1.4 Ga under lower temperatures in a mid-crustal, intracratonic setting. The shear zone was seismogenic in this younger deformation cycle and shows a lateral plastic to frictional strain gradient across a width of 4 to 5 km, from mylonite/ultramylonite with mutually cross-cutting pseudotachylyte, to mylonitic pseudotachylyte, to a system of dispersed pseudotachylyte-bearing fault zones. This trip will examine details of earthquake rupture geometry and dynamics from the base of the seismogenic zone, and will revisit some of the sites presented at a field trip offered for the 125th annual meeting of the Geological Society of America. For more information, contact Joe Allen.

This focus of the trip is the structural geology and fault geochronology of Garden of the Gods. The site at the south end of the Rampart Range fault (RRF) features Laramide backthrusts, bedding plane faults, and curved fault linkages within subvertical Mesozoic strata in the footwall of the RRF. Pervasive deformation band arrays and younger-upon-older reverse faults are components of the complex system. New results of 40Ar/39Ar illite age analysis of shear-generated illite in the Garden and the surrounding region provide evidence for the time of formation of the Front Range monocline, to be compared against stratigraphic-biostratigraphic records from the Denver Basin. The field trip will complement an illite geochronology workshop being presented by Elisa Fitz Díaz on 19 June. If time allows, and there is participant interest, we will make a final stop to examine fault-bounded, massive sandstone- and granite-hosted clastic dikes that are associated with the Ute Pass fault. These are newly demonstrated to be Neoproterozoic in age.

Paleoproterozoic supracrustal rocks in the region near Big Thompson Canyon, northern Colorado, have long been recognized as a spectacular example of Barrovian metamorphism, preserving a complete sequence from biotite- to migmatite-zones. However, structural evidence for multiple deformation events, multiple generations of classic Barrovian index minerals, the widespread occurrence of non-Barrovian index minerals (e.g., andalusite, cordierite), and sparse geochronological/thermochronological data all suggest the potential for a complex tectonic history that likely spans from 1.8 to 1.4 Ga. This field trip aims to bring together Earth scientists from a broad range of backgrounds to enjoy a day of field structural geology, metamorphic petrology, and Proterozoic tectonics in northern Colorado. We also hope to foster new ideas and research directions that can utilize the Big Thompson Metamorphic Suite for investigating fundamental orogenic processes.

New lithosphere-scale seismic experiments in the northern Rockies show that lower-crustal detachment is the leading hypothesis for the formation of the enigmatic Laramide Rocky Mountains. This hypothesis was originally proposed in the Colorado Front Range on the basis of minor fault analyses and kinematic restorations. Come visit some of the key outcrops that generated this hypothesis and see how they can be linked with regional seismic data to give a unified thrust model for the Rockies. In addition, we will examine the resulting natural fracture systems that provide critical fluid conduits for tight reservoirs in successful resource plays (e.g., shale gas and oil) like the Niobrara Formation of the Denver Basin. For more information, contact Eric Erslev.

Short courses/workshops

Optional, taking place before and after the Forum (June 14, 15, 19, and 20). You must register for these when you register for the Forum (opens in a new window).

The strain analysis workshop will cover the practical use of several current, freely-available software programs for finite strain studies. The programs include the integrated software package EllipseFit by Vollmer, a suite of Mathematica-based programs by Mookerjee, and GeoShear by Paul Karabinos. A free copy of EllipseFit, GeoShear, all Mathematica–based programs, and a trial copy of Mathematica will be provided. Topics will include: collection of oriented samples; Fry-type and Wellman-type analyses; center-point, line, elliptical, and irregular particle digitizing; methods for 2D section ellipse calculation; ellipse data contouring and examination for pre-strain fabrics; polar, Rf-phi graphs, and hyperboloidal projections; unstraining data; use of 3D lineation data; calculation of the strain ellipsoid from multiple section ellipses; statistical analyses, and representing three-dimensional strain data and error regions. The workshop will include topics suitable for levels from undergraduate structural geology laboratories to advanced kinematic-based research projects. Attendees will need to bring a laptop (Windows, Mac, or Linux).

It is likely that most geologists on Earth have used Google Earth to view geologic structures. However, there are a range of less well-known tools that are highly relevant to digital geology research and teaching, including Google Maps Engine, Google Earth Engine, Open Data Kit, TourBuilder, and Google Glass Development Kit. The workshop will aim to take participants beyond the basics of geo-browsing by demonstrating how to design virtual field trips incorporating active student engagement and how to use Google mapping technologies to enhance visualization of field data with virtual outcrops, emergent cross sections, and interactive screen overlays. There will be content suited to those who wish to develop their own visualizations and also those that wish to learn about effective use of existing resources.

Visible Geology is a web-based interactive visualization and modelling program for use in introductory and structural geology classes. Students can use this program to create their own geologic block models with events such as deposition of beds, folds, faults, unconformities, and igneous intrusions. Once a geologic history has been created, it is possible to see the geology interacting with various topographies, create cross sections and boreholes, or scroll through the geologic history. The program aids in 3D visualization techniques that are hard to teach by traditional paper-based methods.

The workshop will introduce participants to the capabilities of Visible Geology as well as prototypes of several new interactive geoscience visualizations and to provide an opportunity for participants to develop and refine activities using these web-based tools to help structural geology students better visualize 3D structures.

In a pre-workshop webinar, we will introduce the features of Visible Geology and have participants prepare an exercise that utilizes features of the program. Sample topics for exercises include apparent dip, interference folding, stereonet visualization, cross-sections, and outcrop patterns. The workshop will be devoted to presenting and critiquing participant developed activities that leverage the interactive visualization capabilities of Visible Geology. Additionally, we will present prototypes of new interactive geoscience visualizations and solicit feedback from the community.

The course deals with shear sense indicators in ductile and brittle shear zones, with a focus on the recognition and correct interpretation of shear sense indicators in thin section and in the field. The course consist of introductory lectures on the theory of kinematics and shear sense indicators, and a lectures on practical field aspects of shear sense analysis. Quantitative analysis of kinematic vorticity will be briefly treated. The afternoon will be spent working through a large number of thin sections of with shear sense indicators, mostly from mylonites. This one day course on shear sense indicators is an extended part of the regular Microtectonics course in Mainz, Germany.

The goal of this workshop is to review fundamentals and updates on Ar-Ar illite dating applied to determine the age of activity of faults and folds. This workshop will consists of three parts: 1) History and theoretical basis of Ar-Ar illite dating; 2) Illite XRD characterization; 3) Ar-Ar illite systematics; 4) Examples of application to the foreland the North American Cordillera: Fold dating in the Mexican Fold Thrust Belt and Fault and fold dating of the Front Ranges Monocline.

A team of folks affiliated with UNAVCO and its member institutions has developed a flexible curricular module about infinitesimal/instantaneous crustal strain that utilizes GPS data that are published online by the EarthScope Plate Boundary Observatory. The goals of this short course are (1) to teach folks how to use the velocity data from three non-colinear GPS sites to compute average crustal strain, (2) to present the associated curricular resources that we have developed, and (3) to discuss how these curricular resources might be adapted for use in structural geology, geophysics or tectonics courses. Early tests at several universities have indicated that undergraduate students have been able to apply the crustal strain information they have computed, using GPS velocity data, to form a preliminary understanding of the interplay between tectonic setting, volcanism, active faulting and seismicity. Supplementary documents developed for this project enable students to apply (or learn) some mathematics and programming skills related to instantaneous strain analysis using GPS data. The development team is interested in spreading use of these resources, and is actively seeking feedback from students, teachers, and those with a research interest in GPS that will lead to future improvements. More information about the module.

30 years after the widespread deployment of personal computers, shouldn't we really be teaching our students how to solve structure problems by computing rather than increasingly arcane graphical methods? Shouldn't they know how their software tools that they rely on for their own science actually work? The purpose of this workshop is to show how to teach a typical structural geology lab using the same math that computer programs use: linear algebra and vector operations. A side benefit of this approach is that it provides fundamental background for understanding the basics of continuum mechanics, what it means to say that stress and strain are tensors, and teach transformations, an operation so fundamental to all of earth science that it is hard to believe that most of us waited so long to learn it! The problems to be solved are familiar: apparent dip, 3 point problems, map thickness, rotations, down-plunge projections, P&T axes for faults and earthquakes, and 1d strain gradients. This approach assumes no previous knowledge of linear algebra on the part of the students; The purpose is to teach them the simple concepts of linear algebra as efficient ways of solving problems of geological interest. No prior computing knowledge is assumed either as all problems are done in spreadsheets. Workshop participants will need access to a personal computer (either Mac or Windows) with Excel or some similar spreadsheet installed. We will also use my program, GeolMapDataExtractor to check answers as well as demonstrate how one can explore error propagation in classic structural geology calculations, and Google Earth for display of some results.

Workshop description: This one-day course will provide faculty, students and professionals with an introduction to Terrestrial Laser Scanning (TLS - a.k.a., ground-based lidar). TLS provides high-resolution three-dimensional images of geologic features, and has emerged as a powerful tool for applications ranging from outcrop mapping to analysis of earth surface processes. The course will focus on TLS technology, data collection, processing and analysis, and examples of science applications. A combination of lectures and hands-on demonstrations of TLS equipment and data processing will be used.


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