New outcrops created during the 1983 draining of Watauga Lake within the Mountain City window exposed the Little Pond Mountain thrust zone, marked by more than 200 m of Max Meadows-type carbonate breccia. The breccias are derived from the lower Rome Formation of the hanging wall, which is thrust 12 km over younger Rome beds. The upper boundary of the fault zone is gradational, beginning with intact shales and dolostones that become progressively disaggregated by boudinage and disharmonie folding, grading into a thick zone of polymict breccia in contact with Rome shales in the footwall. The brecciation is thrust related and tied to a particular stratigraphie horizon. Extreme competency contrast between brittlely deformed dolostones and shales, and interlayered, plastically deformed calcitic laminites is inconsistent with the current mineralogy and suggests the presence of weak evaporite-rich layers during deformation. Within the fault zone, these weak beds grade into the breccia matrix. Boudinaged dolostones and shales form clasts in a breccia mixed by mesoscopic isoclinal folding. Raindrop prints, ubiquitous mudcracks, and evaporite crystal molds in the lower Rome Formation are consistent with evaporative depositional environments. The breccias also exhibit features of evaporite solution-collapse breccias, including sedimentary cavity fillings. Pétrographie evidence for vanished evaporites includes anhydrite inclusions, evaporite crystal molds, and chert nodules pseudomorphous after anhydrite. A sparry calcite mosaic that apparently replaced evaporite laminites also forms the breccia matrix. The evaporite hypothesis is supported by interbedded dolostone and anhydrite discovered in the subsurface at the base of the Rome. The Watauga Lake breccias are postulated to be the result of décollement thrusting within a dolostone-anhydrite sequence at the base of the Rome Formation, producing a polymict evaporite-matrix breccia, which after deformation, underwent local solution collapse and widespread replacement of anhydrite by calcite. The Max Meadows breccias have long been considered unique, but a review of published work shows that these rocks and occurrences at Watauga Lake are identical in many ways to Rauhwacken (cornieules) of Europe and similar carbonate breccias in Nevada, the northern U.S. and Canadian Rockies, Ireland, and southern England, all of which have been interpreted as deformed carbonate-evaporite sequences. There are also similarities to carbonate breccias in Nova Scotia, northern Michigan, and the foreland of the Canadian Rockies that are purely the result of evaporite dissolution. These comparisons show that, in a given occurrence, thick carbonate breccias with similar diagenetic histories may originate from either décollement thrusting, evaporite dissolution, or a combination of the two processes.

Abstract Outcrops of extensive Max Meadows tectonic breccia are along the bluffs overlooking New River at Pepper, Virginia (Fig. 1). A few feet (m) northeast of the New River bridge on Virginia 114 turn north into a dirt road. Parkin the wide area just onto the dirt road and do not block the driveway to the private house. Do not drive to the outcrops on the dirt road which is a railroad right of way. Walk northeast about 1,000 ft (300 m) to the railroad tracks along the dirt road.

ABSTRACT A laterally discontinuous sandstone at the south end of the Tellico-Sevier syncline in Blount County, Tennessee, was mapped in 1955 by Robert Neuman and in 1965 by Neuman and Willis Nelson of the U.S. Geological Survey as a “quartzite” that they considered to be the uppermost bed of the Bays Formation (Ordovician). On the basis of new mapping and conodont biostratigraphy, lithostratigraphy, and regional K-bentonite correlations, this sandstone, a distinctive quartz arenite, is reassigned to and correlated with the Clinch Sandstone (Silurian). At the Harrison Branch section (HBRA) in Blount County, in an exposure near the confluence of Harrison Branch and the Little Tennessee River, this sandstone underlies the Devonian Chattanooga Shale, and it overlies ~43 m of gray limestones and shales that are themselves above the red clastic and minor carbonate rocks of the Bays Formation. The limestones and shales between the Bays Formation and this sandstone crop out on a wooded hillside and were apparently not observed by Neuman and Nelson during their mapping of the region. We measured the HBRA section, collected 20 samples from the limestone interval, and processed them for conodonts. These limestones contain a definitive Late Ordovician (Katian) conodont fauna that includes Drepanoistodus suberectus , Plectodina tenuis , Panderodus gracilis , and Phragmodus undatus . On the basis of this fauna, the 40+ m of limestone between the youngest red beds of unequivocal Bays Formation (below) and the quartz arenite (above) can be assigned to the Ordovician P. tenuis zone or younger, making them correlative regionally with limestones of the Trenton Group. Using these new biostratigraphic data combined with existing tephrostratigraphic relations of Ordovician K-bentonites, we identify the overlying sandstone at the HBRA section as an erosional outlier of the Silurian Clinch Sandstone, and we correlate the Ordovician-Silurian-Devonian unconformities at these two localities, which are now better constrained, with unconformities A through F in the Silurian and Devonian of this region, as identified and described in detail at several exposures north and northwest of the Tellico-Sevier syncline, most prominently at outcrops near Wytheville, Seven Mile Ford, and Max Meadows in southwest Virginia, where Devonian strata unconformably overlie Ordovician strata.

Abstract Spruce Run Dam is located near Clinton, Hunterdon County, New Jersey, on Spruce Run, a tributary of South Branch, Raritan River. The dam will retain and supply excess flow for the off-river storage reservoir at Round Valley near Lebanon, New Jersey. The system, constructed by the State of New Jersey, will provide raw water for sale to cities within the State. The dam is earth fill with a select impervious core of weathered glacial drift. Random sections are of weathered shale; riprap is limestone from spillway excavation. The length of the dam, not including the overflow sections and two short dikes is 5400 feet and the height above natural flood plain averages 85 feet. Bedrock is primarily highly faulted, brecciated Kittatinny Limestone bounded on the northeast by older Hardyston Quartzite and on the west by younger Martinsburg Shale. A grout curtain was constructed which spans the limestone belt except for two short stretches where natural water table stands high. The cutoff trench features a concrete grout cap. The upper rock zone beneath much of the fill was blanket-grouted to minimize ground-water movement and sink-hole development. Actual grout quantities were less than estimated. Major construction was completed in 1963.