ABSTRACT This field guide provides an updated synthesis of the stratigraphy and chronology of glacial deposits in central Indiana near the southern limit of glaciation in the midcontinent. Central Indiana contains evidence of multiple glaciations—deposits from the last two glaciations (Oxygen Isotope Stages [OIS] 2 [Wisconsin Episode] and 6 [Illinois Episode]) have been the focus of recent stratigraphic and chronologic investigation. New radiocarbon and optically stimulated luminescence (OSL) dating from outcrop and core has refined the timing of OIS 2 and OIS 6 ice sheet advances, outwash/slackwater aggradation, glacial lake formation, and eolian activity. Radiocarbon ages within or below late Wisconsin till from three sites within 5 km (3 mi) of the late Wisconsin maximum limit indicate an age of 24.0 k cal yr B.P. for maximum OIS 2 ice sheet extent in central Indiana, consistent with chronology from Illinois and Ohio. A subsequent >50 km (31 mi) readvance (21.6 k cal yr B.P.) across central Indiana came within 10 km (6 mi) of the maximum limit and in the western part of the field-trip area, terminated in glacial Lake Eminence. The start of outwash aggradation and associated slackwater sedimentation in the West Fork White River valley and tributaries began ca. 27 k cal yr B.P. and continued until ca. 20.5 k cal yr B.P., representing the timing of ice sheet advance into and out of the paleo–White River drainage basin. Ice sheet advance and retreat rates average ~40 m/yr before and after the global Last Glacial Maximum (ca. 26−21 k cal yr B.P.) when ice was within ~50 km of the late Wisconsin maximum. OSL dating of pre-Wisconsin outwash and glacio-lacustrine sediment return ages between ca. 218 and 127 ka, confirming deposition during OIS 6. These ages document spatially complex sedimentation in bedrock valleys beyond the Wisconsin limit.

Abstract In engineering terms, all materials deposited as a result of glacial and periglacial processes are transported soils. Many of these deposits have engineering characteristics that differ from those of water-lain sediments. In the UK, the most extensive glacial and periglacial deposits are tills. Previously, engineering geologists have classified them geotechnically as lodgement, melt-out, flow and deformation tills, or as variants of these. However, in this book tills have been reclassified as: subglacial traction till, glaciotectonite and supraglacial mass-flow diamicton/glaciogenic debris-flow deposits (see Chapter 4 , Sections 4.1 – 4.3 ). Because this classification is new, it is not possible to relate geotechnical properties and characteristics to the subdivisions of the new classification. Consequently, the domain/stratigraphic classification, recently developed by the British Geological Survey and others, has been used and their geotechnical properties and characteristics are discussed on this basis. The geotechnical properties and characteristics of the other main glacial and periglacial deposits are also discussed. For some of these (e.g. glaciolacustrine deposits, quick clays and loess), geohazards relating to the lithology and/or fabric of the deposit are discussed along with their properties. Other geohazards that do not relate to lithology and/or fabric are discussed separately as either local or regional geohazards. In some cases (e.g. glaciofluvial sands and gravels), the geotechnical properties and behaviour are similar to sediments deposited under different climatic conditions; these deposits are therefore not discussed at length. Similarly, some of the local geohazards that are found associated with glacial and periglacial deposits relate to current climatic conditions and are not discussed here. Examples include land-sliding and highly compressible organic soils (peats).