PHYSIOGRAPHY, PATTERN RECOGNITION, AND PROCESS: LANDSCAPE EVALUATION FROM A GEOLOGIC PERSPECTIVE

“Landscape Evaluation” as a tool for planning has been invoked for several decades by geographers, architects, and others as a strategy for efficiently parsing large regions into a hierarchy of smaller domains with common landforms. Each sub-divided unit includes some repeatable motif that is a function of the interplay between geomorphic processes and the substrate (rocks/sediments). This strategy can be very effective at qualitatively recognizing areas of immediate hazard or opportunity; yet, there is risk of loosing valuable information commonly found on geologic maps. Much can be interpreted from the ages and lithologies of surficial deposits.

A variant paradigm known as the “Morphologic Sequence” can be employed to capture the geologic data implicit in a repeatable motif of landforms. Morphologic sequences have been the “basic building blocks” of geologic maps of glacial deposits in New England for many decades. From active glacial analogs, geographic arrays of landforms are interpreted as sequences of sorted and unsorted sediments that reflect repeating events of glacial advance, retreat, surging outwash, and deposition in quiet water. A landscape assembled by these processes can be subdivided into domains that have common affinities for recharge, aggregate resources, or stable sites. An example from Berrien County, Michigan is presented.

A second pragmatic approach represented by a map of the Surficial Geology and Geomorphology of the Atlantic Coastal Plain is a national scale compilation from multiple sources at many scales. The morphologic sequence paradigm is adapted to integrating stratigraphy and geomorphic processes; coastal plain landforms are presented as sequences of allostratigraphic deposits that facilitate the visualization of transitions in time and space between regional geomorphic systems. This map provides a template for identifying resources and hazards in the context of geologic history, surficial materials, and physiography.