Abstract Sand and sandstone composition of volcanic origin may be clues to the provenance of the sediments and sedimentary rocks. Volcaniclastic provenance studies contribute significantly to unravelling the generation and provenance of sediment under investigation, which in the Aeolian archipelago comprises preserved units of outcrops dominated by lava flows intercalated with airfall tephras as source rocks. The focus of this paper is the study of the petrographical composition and textures of beach sands, which can then be used as a guide in the interpretation of provenance and origin of beach sand(stone)s rich in volcanic debris transported into deeper water. The composition of Aeolian beach deposits defines a single immature petrofacies with a large amount of unweathered glass and mafic minerals. Panarea island is dominated by dacites and new grain categories have been proposed to differentiate this provenance. Surface processes such as mechanical erosion (mass wasting and surface runoff) produce an overestimation of mafic components compared to the felsic components in the beach sand fraction.

ABSTRACT The Indiana Dunes is a name commonly used for the eastern part of the Calumet Lacustrine Plain, generally referring to the large dunes along the coast from Gary, Indiana, eastward to the Michigan state line. However, the Calumet Lacustrine Plain also contains complex coastal landscapes associated with late Wisconsin to Holocene phases of ancestral Lake Michigan (e.g., mainland-attached beaches, barrier beaches, spits), including those formed during quasi-periodic decadal and shorter-term waterlevel variability that characterize modern Lake Michigan (e.g., beach ridges, dunes, interdunal wetlands). Major industrial development and other human activities have impacted the Calumet Lacustrine Plain, often altering these landscapes beyond recognition. Today, geological and paleoenvironmental data are sought to inform regional environmental restoration and management efforts and to increase the resiliency of the coastal landscape to ongoing disturbances. During this field trip, we will examine the relict shorelines and their associated nearshore and onshore features and deposits across the Indiana portion of the Calumet Lacustrine Plain. These features and deposits record the dynamic interaction between coastal processes of Lake Michigan, lake-level change, and long-term longshore sediment transport during the past 15,000 yr. Participants will examine the modern beach, the extensive beach-ridge record of the Tolleston Beach strandplain, a relict dune field, and the large dunes of the modern shoreline, including Mount Baldy. At Mount Baldy, we will focus on the landscape response to human modification of the shoreline. We will also explore the science behind dune decomposition chimneys—collapse features that caused a 6-yr-old boy to become buried more than 3.5 m below the dune surface in 2013 and highlighted a previously unrecognized geologic hazard.