Widespread volcanic components in the eolian Page Sandstone and coeval and overlying Carmel Formation (fluvial, eolian, sabkha, restricted marine) in south-central Utah and adjacent Arizona document extensive Middle Jurassic volcanic activity in the adjacent Cordilleran arc. The most unusual of these volcanic components consist of pure to sandy bentonite fill within trough-shaped eolian scours or super scoops encased in cross-stratified eolian dune deposits. More than 200 of these deposits have been identified in the Page Sandstone near Page, Arizona. Also present are several regional but irregular and discontinuous, thin (several cm) bentonite beds associated with sandy sabkha and eolian sandsheet deposits. Volcanic components are also present as detrital sand- to boulder-size grains in both the Page Sandstone and Carmel Formation. Most of the identified clasts consist of rhyolite tuff fragments. Sand-size clasts occur in fluvial and eolian deposits and cobbles to boulders occur in bedload and mudflow deposits associated with ephemeral stream channels. Bentonites accumulated during brief to possibly extensive lulls in sedimentation. Those with pure composition suggest little to no reworking and rapid accumulation, probably in one ash fall. Volcanic clasts were eroded and transported from extensive rhyolite-tuff aprons in and adjacent to the arc, northward, onto alluvial and coastal plains of the study area. A sharp, northward decrease in grain-size of the largest boulders documents that some volcanic aprons extended to within several kilometers of present Jurassic outcrops. X-ray diffraction (XRD) analyses reveal that the bentonites are predominantly authigenic, long-range ordered, mixed-layered illite/smectite (80%–90% illite, Reischeweite 1–3; Reischeweite is explained in the “Clay Mineralogy” section). Bentonites in underlying and overlying formations occur as randomly interstratified illite/smectites with no more than 60% I. Mineralogy of Page bentonites is not produced by regional burial diagenesis, but is a product of local, near-surface diagenetic environment. These bentonites document geochemical alteration of volcanic ash by highly saline, potassic waters in a cyclic wet/dry hydrologic regime. Regional stratigraphic analysis of the Page Sandstone and the coeval and overlying Carmel Formation document the following tectonic events in the region: (1) lower and middle Page—long-term, sporadic accumulation of volcanic ash on a stable, arid coastal plain with increasing fluvial activity late in this episode; (2) upper Page—increased volcanic activity and local rapid subsidence (development of foredeep adjacent to arc uplift); and (3) uppermost Page, overlying Carmel—strong influx of volcanic detritus and reworked sedimentary material. These events document the well-known Middle Jurassic ignimbrite flare-up (ca. 170 Ma) and strong, possibly localized uplift near the southern margin of the Colorado Plateau.

Approximately 14,500 yr ago, Pleistocene Lake Bonneville discharged 4,750 km 3 of water over the divide between the closed Bonneville basin and the watershed of the Snake River. The resulting flood, released near Red Rock Pass, Idaho, followed the present courses of Marsh Creek, the Portneuf River, and the Snake and Columbia Rivers before reaching the Pacific Ocean. For 1,100 km between Red Rock Pass and Lewiston, Idaho, the Bonneville Flood left a spectacular array of flood features that have allowed for geologic reconstruction and quantitative evaluation of many aspects of the flood hydrology, hydraulics, erosion, and sediment transport. Geologic evidence of maximum flood stages in conjunction with step-backwater flow modeling has furnished estimates of peak discharge and local hydraulic flow conditions for 10 separate reaches along the flood route. Peak discharge was approximately 1.0 million m 3 ·sec −1 at the Lake Bonneville outlet near Red Rock Pass. Downstream, near Lewiston, Idaho, the maximum discharge attenuated to 0.57 to 0.62 million m 3 ·sec −1 . In part, attenuation of the peak discharge was probably the result of flow storage in the wide alluvial valleys of the western Snake River Plain. Diverse geologic and geomorphic environments along the flood route resulted in large spatial variations in the channel geometry as the flood moved downstream. Consequently, the local hydraulic conditions (flow depth, velocity, boundary shear stress) of the Bonneville Flood varied substantially within and between the study reaches. The rate of energy expenditure was also highly varied; local calculated stream power magnitudes ranged from less than 10 watts·m −2 in ponded reaches to more than 100,000 watts·m −2 in major constrictions. More than 50% of the total energy loss at peak discharge was expended over a distance that encompassed less than 6% of the flood route. These spatial variations in local hydraulic conditions were profoundly important in controlling the distribution of flood processes and the resulting flood features. The deposition of tractively transported cobbles and boulders (measured clast diameters ranged from less than 10 cm to more than 10 m) were deposited in reaches of decreasing flow competence within quantitatively definable limits. The hydraulic conditions at areas of erosion were more difficult to precisely evaluate; however, erosion of basalt bedrock was primarily in reaches that had stream power magnitudes that exceeded 20,000 watts·m −2 . Cavitation was probably an important erosional process in areas of most intense flow conditions.

Groundwater resources associated with sediments filling the Marion and Mahomet Valley Sections of the Lafayette Bedrock Valley System vary from miniscule to substantial, reflecting the wide range of glacigenic aquifer facies contained in the fill. These aquifer facies include braid-stream deposits that range from thin units within till sequences to immense, valley-filling masses. Also included is a variety of proximal to distal, subaerial to subaqueous, fan and fan-delta deposits; these range from thick masses of ice-proximal, cobbly rubble interspersed with thin diamicts and clays, to thin, discontinuous lentils of sand confined within lacustrine clays. Valley-fill aquifers are confined by capping till units, except where exhumed at the crossings of the Maumee-Wabash Trough (modern Wabash River Valley). A variety of aquifers typically are available within the valley-capping sediments; for this reason, much of the deep valley-fill has not been extensively explored or developed. Some valley-fill aquifers are so thin and/or deeply buried that their exploitation is unlikely, but others are so thick and areally extensive that exploitation easily can support sustainable yields of tens of millions of gallons per day.

The major deglacial-phase deposits of eastern Maine include stratified end moraines, single and amalgamated ice-margin delta complexes, extensive segmented esker systems that link with marine deltas and fans, and a fossiliferous glacial marine mud (the Presumpscot Formation) that is interbedded with, or drapes, the other deposits. Previous work has determined that deposition within the 40-km-wide swath, which is now the modern coastal zone, occurred between 13,500 and 12,500 B.P. Detailed mapping, measurement of stratigraphic sections and paleocurrents, and calculation of drainage basin area and volume of sediment bodies have led to a better understanding of lithofacies assemblages, depositional processes, sediment sources, and regional geometry of these deposits. The “stratified end moraines,” better described as assemblages of marine fans, measure as much as 15 m high, 100 m wide, and 16 km in length, and were deposited along ice lobe fronts. Proximal vertical sequences are dominated by 15- to 30-cm-thick beds of poorly sorted, pebble-to-cobble gravel locally interbedded with gravelly diamict. Well-sorted, matrix-less (“open-work”) pebble/cobble gravel occurs in channel forms that can be traced tens of meters laterally. Distal sequences consist of laminated beds of medium-to-fine sand capped by silt drapes; climbing ripple cross-stratification is uncommon, and some diamict beds are present. Lithofacies of the delta front, prodelta, and esker core (ice-tunnel deposits) are remarkably similar to those of the fans, differing only in greater degree of dip (deltas), and clast size (ice-tunnel deposits). Paleocurrents of fans show a large dispersion, in some instances indicating flow parallel to the inferred ice margin; proximal beds are deformed, indicating an active ice margin. The ice-margin fan and delta complexes have a combined area of 250 km 2 and total volume of nearly 5 billion m 3 , which strongly suggests that the 2,400-km-long ice-tunnel system (including tributaries) was active along its entire length in order to supply needed sediment. Ice-tunnel deposits filled the distal ends of tunnels as the active ice margin retreated. The geometry and volume of deltas, fans, and ice-tunnel deposits, together with the time constraints, indicate deposition into marine waters at the margin of a complex, multi-lobate, grounded, warm-based ice sheet.

Approximately 105,000 yr ago (based on uranium-series dating), waves in a giant wave train swept up to an elevation of about 375 m on the island of Lanai. The waves deposited the Hulopoe Gravel, which near the present shoreline consists of basalt boulders, coral fragments, and calcareous beachrock slabs, and near the upper limit of the deposit consists of sand and shell fragments. The maximum heights of similar but lower deposits on nearby islands, when adjusted for their estimated subsidence due to volcanic loading during the past 105,000 yr, indicate that the source of the wave was about 50 km southwest of Lanai. We hypothesize that failure and downward movement of the huge Lanai submarine landslide created an ocean disturbance, which produced waves that rushed across the Lanai reef and beach, picked up limestone and lava fragments, and deposited them high on the island as the Hulopoe Gravel. Backwash from the waves stripped soil and rock from the islands and carried much of it to the sea. The Hulopoe Gravel is 8 m thick in a gulch 200 m inland from the Lanai shoreline, where it consists of three beds, successively, 2, 4, and 2 m thick. These beds are considered to have been laid down by successive waves in the wave train. Each bed consists of two units: a lower unit of basalt and limestone boulders, cobbles, and sand, and an upper bimodal unit of large basalt boulders with a pebbly sand matrix. These subunits are inferred to be deposited from the runup and backwash of each wave. At the upper surface of the Hulopoe Gravel, basalt boulders averaging 0.5 m in diameter are arranged in dunelike ridges about 1 m high and 10 m apart. Nearby, where young streams have cut into and exposed the lower beds of the Hulopoe, clasts at the boundaries between the beds are locally imbricated and dip landward. We interpret these features as aspects of torrential flow and crossbedding created during the high-speed backwash of the great waves.