Adapting geologic field education and research training to new geospatial technologies requires considerable investment of time and money in acquiring new instruments, mastering new techniques, and developing new curriculum in return for dramatically increased mapping capabilities. The University of Southern Maine’s Research Experiences for Undergraduates (REU) Program has developed an integrated system of digital mapping specifically designed for geologic work that involves satellite and optical digital survey instruments, digital imagery, and a variety of mapping techniques. These new digital tools, techniques, and resources are used to explore the nature of crustal deformation in an adventure-based undergraduate field research program that employs sea kayaks for coastal access to island bedrock exposures. This new generation of digital mapping tools enabled the development of new techniques for outcrop surface mapping where we are able to delineate 1–100-m-range mesoscale geologic features that are often overlooked in traditional quadrangle-scale geologic mapping. Maps of extensive exposures in coastal Maine created using these digital techniques continue to reveal new and never-before-seen geologic structures and relationships. Because of this, undergraduate students are able to make meaningful contributions to our base of geologic knowledge and acquire essential geospatial skills, while learning these digital mapping techniques in a research setting. The emphasis we place on teamwork, risk taking, exploration, and discovery as part of the adventure programming aspect of the field component builds a confidence and enthusiasm that extends into the research component of the project, where students are able to develop new analytical methods, applications, and approaches to our field and laboratory work.

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Full article available in PDF version.

Mesozoic dikes in southern Maine occur within a 15–20-km-wide northeast-trending coast-parallel swarm ~150 km in length. The swarm is best exposed from Kittery to Ogunquit, but extends northeast into the Casco Bay area and southwest into New Hampshire. The dikes are dominantly mafic (dolerites and lamprophyres) but syenitic and granitic varieties are also present. Composite and multiple intrusive relations are common. Average dike width is 1.12 m and maximum dike width is ~25 m. Maximum extension values of 23% and dike intensities of 176 dikes/kilometer are found along the interpreted swarm axis. Dike orientations are dominantly northeast-trending and steeply dipping with apparent maxima at N60°E, N45°E, and N35°E, as well as minor northwest trends. These trends reflect a strong structural control on intrusion by the N60°E vertical bedding and a N45°E vertical cleavage in the host Kittery Formation. The horizontal component for dike dilation is dominantly N55°W-S55°E, which results in many sinistral-oblique opening directions and left-stepping en echelon offsets for the more structurally controlled dikes. Most of the mafic dikes were intruded between the syenite-alkaline granite phase and the later biotite granite phase of the Triassic Agamenticus alkaline intrusive complex. Dike intrusion was also contemporaneous with the emplacement of Triassic explosive igneous breccias at Gerrish Island, but prior to the intrusion of the Late Cretaceous Cape Neddick gabbro complex. A linear dike swarm: central intrusive complex model based on the Tertiary igneous province of northwest Scotland is adopted for this phase of early Mesozoic magmatism. The linear coast-parallel dike swarm and associated Triassic Agamenticus alkaline intrusive complex in southern Maine are part of the coastal New England igneous province of McHone and Butler; a 500-km-long, north-northeast-trending zone of crustal extension that includes the early Mesozoic dikes of eastern Massachusetts and Rhode Island to the southwest developed during Triassic rifting.