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Call for Papers: 2010 GSA Annual Meeting & Exposition, p. 14 VOL. 20, No. 4/5 A PUBLICATION OF THE GEOLOGICAL SOCIETY OF AMERICA APRIL/MAY 2010 The digital revolution in geologic mapping Inside: L Call for GSA Committee Service, p. 46 L In Memoriam, p. 49 L Groundwork: Paleotempestology and the pursuit of the perfect paleostorm proxy, p. 52 VOLUME20,NUMBER4/5▲APRIL/MAY2010 SCIENCE ARTICLE GSA TODAY publishes news and information for more than 22,000 GSA members and subscribing libraries. GSA TODAY 4 The digital revolution in (ISSN 1052-5173 USPS 0456-530) is published 11 times per geologic mapping year, monthly, with a combined April/May issue, by The Steven J. Whitmeyer, Jeremy Geological Society of America®, Inc., with offices at 3300 Penrose Place, Boulder, Colorado. Mailing address: P.O. Box Nicoletti, and Declan G. De Paor 9140, Boulder, CO 80301-9140, USA. Periodicals postage paid at Boulder, Colorado, and at additional mailing offices. 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Sajban 48 GSA Foundation Update ADVERTISING: 49 In Memoriam Classifieds & Display: Ann Crawford, +1-800-472-1988, ext. 1053, +1-303-357-1053, Fax +1-303-357-1070; 50 Classifi ed Advertising [email protected] 50 GeoCorps™ America Introduces Fall and Winter Positions GSA ONLINE: www.geosociety.org 52 Groundwork: Paleotempestology and the pursuit Printed in the USA using pure soy inks. of the perfect paleostorm proxy 54 Coming in June’s GSA Today 54 Publication Highlights Errata 1. On pages 7 and 8 of the Feb. 2010 science article (v. 20, no. 2, p. 4–9), weathering rates listed as mm yr−1 and mm k.y.−1 were inadvertently changed to m yr−1 and m k.y.−1. Please note that the correct measurement is millimeters, not meters. 2. The participants list for the Penrose Conference on p. 24–25 of the Feb. 2010 issue (v. 20, no. 2) did not include one attendee, George T. Stone, of Milwaukee Area Technical College. The digital revolution in geologic mapping Steven J. Whitmeyer, Jeremy Nicoletti, James Madison countless hours of classifying, measuring, cataloguing, and in- University, Dept. of Geology & Environmental Science, MSC terpolating rock units across field areas at outcrop to continen- 6903, Harrisonburg, Virginia 22807, USA; and Declan G. tal scales. Over the years, the means of transportation for De Paor, Old Dominion University, Dept. of Physics, Norfolk, fieldwork advanced from horseback to four-wheel drive vehi- Virginia 23529, USA cles, but the basic methods of field data collection and presen- tation remained largely unchanged. The first years of the twenty-first century saw a major advance ABSTRACT in the methods of field data acquisition and geologic map presen- Geologic field data collection, analysis, and map compilation tation. This was facilitated by three main technological advances: are undergoing a revolution in methods, largely precipitated by (1) the descrambling of global positioning system (GPS) satellite global positioning system (GPS) and geographic information signals, (2) the advent of affordable mobile computers capable of system (GIS) equipped mobile computers paired with virtual running geographic information system (GIS) software in the globe visualizations. Modern, ruggedized personal digital as- field, and (3) the universal availability of free, Web-based virtual sistants (PDAs) and tablet PCs can record a wide spectrum of globes (also known as digital globes or geobrowsers). Although geologic data and facilitate iterative geologic map construction GPS had been operational since the mid-1990s, it wasn’t until and evaluation on location in the field. Spatial data, maps, and 2000, when Selective Availability was discontinued, that GPS be- interpretations can be presented in a variety of formats on vir- came effective as a precise positioning tool for the general popu- tual globes, such as Google Earth and NASA World Wind, given lace (White House Office of Science and Technology Policy only a basic knowledge of scripting languages. As a case study, [OSTP], 2000). Manufacturers began producing inexpensive we present geologic maps assembled in Google Earth that are handheld and car-mounted GPS devices as backpacking and mo- based on digital field data. Interactive features of these maps torized travel aids. At the same time, computer manufacturers include (1) the ability to zoom, pan, and tilt the terrain and started marketing portable personal digital assistants (PDAs) and map to any desired viewpoint; (2) selectable, draped polygons tablet PCs capable of integrating GPS with GIS software for mo- representing the spatial extent of geologic units that can be bile digital data collection. Today, advanced mobile computing rendered semi-transparent, allowing the viewer to examine the systems, such as the Trimble Explorer series and xPlore tablet underlying terrain; (3) vertical cross sections that emerge from PCs, are ruggedized and water-resistant enough to handle the the subsurface in their proper location and orientation; typical bumps, scratches, and rain showers common to geologic (4) structural symbols (e.g., strike and dip), positioned at out- field mapping and research. crop locations, that can display associated metadata; and Techniques for the digital presentation of geologic maps ad- (5) other data, such as digital photos or sketches, as clickable vanced during the late twentieth century using an assortment objects in their correct field locations. of proprietary platforms (e.g., Selner and Taylor, 1993; Condit, Google Earth–based interactive geologic maps communicate 1995). Recent developments utilize free and almost universally data and interpretations in a format that is more intuitive and easy accessible global terrain models within Web-based virtual to grasp than the traditional format of paper maps and cross sec- globes, such as NASA World Wind, Google Earth, and Micro- tions. The virtual three-dimensional (3-D) interface removes soft Virtual Earth. These “geobrowsers” generally support the much of the cognitive barrier of attempting to visualize 3-D fea- open-source scripting language KML (Keyhole Markup Lan- tures from a two-dimensional map or cross section. Thus, the guage), an XML-derived language that facilitates user manipu- digital revolution in geologic mapping is finally providing geosci- lation of a geobrowser environment. KML scripting has enabled entists with tools to present important concepts in an intuitive geoscientists, as well as other producers of spatial data sets, to format understandable to the expert and layperson alike. display field data and maps in a virtual three-dimensional (3-D) interface. Provided the user has an active, reasonably fast Inter- INTRODUCTION net connection, the possibilities for exploring an ever-expand- The presentation of spatial geologic data as maps and cross ing collection of geospatial data sets from locations around the sections essentially began with Cuvier and Brongniart’s (1808) globe are almost unlimited. Users can bypass the requirement map of the Paris Basin and Smith’s (1815) geologic map of for an active Internet connection by loading pertinent data and England and Wales. Their approach to presenting field data as maps into the cache of a geobrowser, thereby enabling access color-coded units in recognizable map formats became the de to a virtual 3-D interface on location in the field.