Abstract Volcanoes are not randomly distributed over the Earth's surface. Most are concentrated on the edges of continents, along island chains, or beneath the sea where they form long mountain ranges. More than half of the world's active volcanoes above sea level encircle the Pacific Ocean (see Fig. 1 ). The concept of plate tectonics explains the locations of volcanoes and their relationship to other large-scale geologic features. The Earth's surface is made up of a patchwork of about a dozen large plates and a number of smaller ones that move relative to one another at <1 cm to ~10 cm/yr (about the speed at which fingernails grow). These rigid plates, with average thickness of ~80 km, are separating, sliding past each other, or colliding on top of the Earth's hot, viscous interior. Volcanoes tend to form where plates collide or spread apart ( Fig. 2 ) but can also grow in the middle of a plate, like the Hawaiian volcanoes ( Fig. 3 ). Of the more than 1,500 volcanoes worldwide believed to have been active in the past 10,000 years, 169 are in the United States and its territories ( Ewert et al., 2005 ) (see Fig. 4 ). As of spring 2007, two of these volcanoes, Kilauea and Mount St. Helens, are erupting, while several others, including Mauna Loa, Fourpeaked, Korovin, Veniaminof, and Anatahan, exhibit one or more signs of restlessness, such as anomalous earthquakes, deformation of the volcano's surface, or changes in volume and composition

Abstract The primary objective of this two-day field trip is to examine sediments from the Evans Creek stade of the early Fraser Glaciation at four key sections along the Skagit River near Concrete and the shoreline of Ross Lake. These sediments provide important new information on the timing and extent of alpine glacier advances during the Evans Creek stade (early Fraser Glaciation). In lower Skagit valley at Cedar Grove, glacial drift overlies an organic bed that yielded a radiocarbon age of 25,040 14 C yr B.P.; this age is a maximum limiting date for the Evans Creek stade. Three radiocar-bon ages within 400 years of 24,000 14 C yr B.P. record damming of upper Skagit valley by the Big Beaver alpine glacier. The ice dam created glacial Lake Skymo, which persisted until at least 18,020 14 C yr B.P., suggesting that Cascade glaciers remained at advanced positions throughout most of the Evans Creek stade. However, growth of a forest on early Evans Creek drift at Cedar Grove 20,730 14 C yr B.P. requires at least some recession of the Baker valley glacier. An increase in the number of lowland and montane macrofossils in glacial Lake Skymo sediments after 20,770 14 C yr B.P. is consistent with a mid–Evans Creek stade warm interval. Sometime after 20,730 14 C yr B.P., the Baker valley glacier overrode the forest bed and deposited till at Cedar Grove. The advance dammed Skagit River and created glacial Lake Concrete, which persisted until about 16,400 14 C yr B.P.

Abstract Washington State is second only to California in terms of wine produced in the United States, and some of its vineyards and wines are among the world’s best. Most Washington vineyards are situated east of the Cascades on soils formed from Quaternary sediments that overlie Miocene basaltic rocks of the Columbia River Flood Basalt Province. Pleistocene fluvial sediments were deposited during cataclysmic glacial outburst floods that formed the spectacular Channeled Scabland. Late Pleistocene and Holocene sand sheets and loess form a variable mantle over outburst sediments. Rainfall for wine grape production ranges from ~6-18 in (150-450 mm) annually with a pronounced winter maximum and warm, dry summers. This field trip will examine the terroir of some of Washington’s best vineyards. Terroir involves the complex interplay of climate, soil, geology, and other physical factors that influence the character and quality of wine. These factors underpin the substantial contribution of good viticultural practice and expert winemaking. We will travel by bus over the Cascade Mountains to the Yakima Valley appellation to see the effects of rain shadow, bedrock variation, sediment and soil characteristics, and air drainage on vineyard siting; we will visit the Red Mountain appellation to examine sites with warm mesoclimate and soils from back-eddy glacial flood and eolian sediments; the next stop will be the Walla Walla Valley appellation with excellent exposures of glacial slackwater sediments (which underlie the best vineyards) as well as the United States’ largest wind energy facility. Finally, we will visit the very creatively sited Wallula Vineyard in the Columbia Valley appellation overlooking the Columbia River before returning to Seattle.