Abstract Detailed geologic mapping and new SHRIMP (sensitive high-resolution ion microprobe) U-Pb zircon, Ar/Ar, Lu-Hf, 14 C, luminescence (optically stimulated), thermochronology (fission-track), and palynology reveal the complex Mesoproterozoic to Quaternary geology along the ~350 km length of the Blue Ridge Parkway in Virginia. Traversing the boundary of the central and southern Appalachians, rocks along the parkway showcase the transition from the para-autochthonous Blue Ridge anticlinorium of northern and central Virginia to the allochthonous eastern Blue Ridge in southern Virginia. From mile post (MP) 0 near Waynesboro, Virginia, to ~MP 124 at Roanoke, the parkway crosses the unconformable to faulted boundary between Mesoproterozoic basement in the core of the Blue Ridge anticlinorium and Neoproterozoic to Cambrian metasedimentary and metavolcanic cover rocks on the western limb of the structure. Mesoproterozoic basement rocks comprise two groups based on SHRIMP U-Pb zircon geochronology: Group I rocks (1.2-1.14 Ga) are strongly foliated orthogneisses, and Group II rocks (1.08-1.00 Ga) are granitoids that mostly lack obvious Mesoproterozoic deformational features. Neoproterozoic to Cambrian cover rocks on the west limb of the anticlinorium include the Swift Run and Catoctin Formations, and constituent formations of the Chilhowee Group. These rocks unconformably overlie basement, or abut basement along steep reverse faults. Rocks of the Chilhowee Group are juxtaposed against Cambrian rocks of the Valley and Ridge province along southeast- and northwest-dipping, high-angle reverse faults. South of the James River (MP 64), Chilhowee Group and basement rocks occupy the hanging wall of the nearly flat-lying Blue Ridge thrust fault and associated splays. South of the Red Valley high-strain zone (MP 144.5), the parkway crosses into the wholly allochthonous eastern Blue Ridge, comprising metasedimentary and meta-igneous rocks assigned to the Wills Ridge, Ashe, and Alligator Back Formations. These rocks are bound by numerous faults, including the Rock Castle Creek fault that separates Ashe Formation rocks from Alligator Back Formation rocks in the core of the Ararat River synclinorium. The lack of unequivocal paleontologic or geochronologic ages for any of these rock sequences, combined with fundamental and conflicting differences in tectonogenetic models, compound the problem of regional correlation with Blue Ridge cover rocks to the north. The geologic transition from the central to southern Appalachians is also marked by a profound change in landscape and surficial deposits. In central Virginia, the Blue Ridge consists of narrow ridges that are held up by resistant but contrasting basement and cover lithologies. These ridges have shed eroded material from their crests to the base of the mountain fronts in the form of talus slopes, debris flows, and alluvial-colluvial fans for perhaps 10 m.y. South of Roanoke, however, ridges transition into a broad hilly plateau, flanked on the east by the Blue Ridge escarpment and the eastern Continental Divide. Here, deposits of rounded pebbles, cobbles, and boulders preserve remnants of ancestral west-flowing drainage systems. Both bedrock and surficial geologic processes provide an array of economic deposits along the length of the Blue Ridge Parkway corridor in Virginia, including base and precious metals and industrial minerals. However, common stone was the most important commodity for creating the Blue Ridge Parkway, which yielded building stone for overlooks and tunnels, or crushed stone for road base and pavement.

The concept of sustainability has been redefined over the past two decades, with growing realization that simply avoiding most impacts to human and environmental resources is not enough to counter the long-term losses created by current and past economic activities. The production of mineral resources and fossil fuels would seem to be activities that cannot, by definition, be sustainable, but extractive industries provide necessary contributions to society. By holding extractive industries to higher standards than we do today, they can become part of a globally sustainable approach that will benefit society far beyond the sites of resource extraction. Truly sustainable living in the future can only be accomplished if the current effect of our presence is restorative (net positive impact) rather than just impact-neutral. One way for the mineral industry to participate is for companies to accumulate a capital fund (by saving a portion of the annual depletion) that is used to mitigate damage and restore habitat to a greater extent than would be required to mitigate impacts from current activities alone. This form of sustainability thus becomes restorative. Restorative sustainability requires that all current impacts be evaluated using full-cost accounting. Global impacts cannot be ignored, and the values of priceless things must be honored by preventing their destruction. With respect to social resources, all stakeholders must have a say, and full disclosure is required. Active acceptance by society over multiple generations is important, and costs incurred to ensure true sustainability must be accepted as a cost of doing business.

Recent expansion in the demand for clean-energy and efficient technologies has led to demand for a variety of exotic, rare, or “strategic” metals. Some of these are physically rare, while others are economically or politically unavailable. In order to fill the gap between supply and demand, and to ensure future resources, various unconventional resources are being examined. This chapter discusses deep-ocean and industrial ecology–based solutions for providing these materials and provides considerations of how such resources can be considered within a framework of sustainable development. Specifically, this chapter addresses the importance of the social elements of the rare metals supply chain, examining the elements of local stakeholder impact and the broader, global public interest represented by the technologies utilizing such metals. The chapter also considers how technical and environmental knowledge derived from geosciences can have an impact on stakeholder support for alternative resources.

Electric vehicles have been promoted to reduce greenhouse gas emissions and lessen U.S. dependence on petroleum for transportation. Growth in U.S. sales of electric vehicles has been hindered by technical difficulties and the high cost of the lithium-ion batteries used to power many electric vehicles (more than 50% of the vehicle cost). Groundbreaking has begun for a lithium-ion battery factory in Nevada that, at capacity, could manufacture enough batteries to power 500,000 electric vehicles of various types and provide economies of scale to reduce the cost of batteries. Currently, primary synthetic graphite derived from petroleum coke is used in the anode of most lithium-ion batteries. An alternate may be the use of natural flake graphite, which would result in estimated graphite cost reductions of more than US$400 per vehicle at 2013 prices. Most natural flake graphite is sourced from China, the world’s leading graphite producer. Sourcing natural flake graphite from deposits in North America could reduce raw material transportation costs and, given China’s growing internal demand for flake graphite for its industries and ongoing environmental, labor, and mining issues, may ensure a more reliable and environmentally conscious supply of graphite. North America has flake graphite resources, and Canada is currently a producer, but most new mining projects in the United States require more than 10 yr to reach production, and demand could exceed supplies of flake graphite. Natural flake graphite may serve only to supplement synthetic graphite, at least for the short-term outlook.

Sulfur dioxide (SO 2 ) enters the atmosphere through natural and anthropogenic processes. Mitigation of SO 2 emissions from many industrial activities has produced by-product sulfur and by-product synthetic gypsum essentially mineralogically identical to the primary materials extracted using mines and wells. Regulation to reduce anthropogenic SO 2 emissions was one of the first environmental protection efforts in the United States, which later became mandated under the Clean Air Act Amendments of 1990. The availability of by-product sulfur has increased over the years, and following the closure of the last domestic sulfur mine in 2000, it became the only domestic source of elemental sulfur in the United States. The most widely adopted means of reducing SO 2 emissions from coal-burning facilities has been to install flue gas desulfurization (FGD) equipment, which produces synthetic FGD gypsum. The decrease in SO 2 emissions since 1980 has significantly improved air quality in parts of the United States. By-products from these activities have replaced the supply of products, such as elemental sulfur, sulfuric acid (H 2 SO 4 ), and gypsum, through substitution of by-product for primary mining of these mineral commodities. The cascading effect of efforts in the United States to mitigate SO 2 emissions from multiple sources through the enactment of the Clean Air Act, and its amendments, has resulted in more than improved air quality alone. It has also, through the increasing availability of environmental products of SO 2 mitigation, such as by-product H 2 SO 4 , elemental sulfur, and by-product synthetic gypsum, reduced the environmental impacts of mining these materials from mineral deposits.