Global sea-level rise increased during the twentieth century from 1.5 to 3.0 mm/yr and is expected to at least double over the next few decades. The Western Louisiana and Texas coast is especially vulnerable to sea-level rise due to low gradients, high subsidence, and depleted sediment supply. This Memoir describes the regional response of coastal environments to variable rates of sea-level rise and sediment supply during Holocene to modern time. It is based on results from more than six decades of research focused on coastal and nearshore stratigraphic records. The results are a wake-up call for those who underestimate the potential magnitude of coastal change over decadal to centennial time scales, with dramatic changes caused by accelerated sea-level rise and diminished sediment supply.

Abstract During the Pleistocene, the Laurentian Ice Sheet extended southward into western Pennsylvania. This field trip identifies a number of periglacial features from the Pittsburgh Low Plateau section to the Allegheny Mountain section of the Appalachian Plateaus Province that formed near the Pleistocene ice sheet front. Evidence of Pleistocene periglacial climate in this area includes glacial lake deposits in the Monongahela River valley near Morgantown, West Virginia, and Sphagnum peat bogs, rock cities, and patterned ground in plateau areas surrounding the Upper Youghiogheny River basin in Garrett County, Maryland, and the Laurel Highlands of Somerset County, Pennsylvania. In the high lying basins of the Allegheny Mountains, Pleistocene peat bogs still harbor species characteristic of more northerly latitudes due to local frost pocket conditions.

Ethnogeology, the scientific study of geological knowledge of groups such as indigenous peoples, can be combined with mainstream geological sciences to enhance our understanding of Earth systems. The Amazon rain forest has been extensively studied by both mainstream scientists and indigenous researchers. We argue that knowledge of Amazonian geology and hydrology held by indigenous Uitoto experts is valid, empirically based, and, in many cases, more nuanced than mainstream scientific knowledge. We also argue that knowledge sharing between mainstream and indigenous researchers can improve geological and environmental knowledge on both sides and provide solutions for current environmental problems such as increased pressure on water resources and global warming. We applied methods from ethnography and earth science to examine the traditional ecological knowledge of an Amazonian tribe in Colombia, the Uitoto, about water, and how that knowledge correlates with that of mainstream earth scientists. The study demonstrates how ethnogeology can be applied in a water-rich environment to: (1) compare knowledge about the natural history of an area, (2) study the geological resources available and their uses, and (3) examine the bases of native classification schemes using mainstream science methods. We found parallels and complementary concepts in the two bodies of knowledge. Our results suggest that the Uitoto have a meticulous taxonomy for water and wetlands—knowledge that is essential for protecting, conserving, and managing their water resources.