Supplemental Material: Detrital zircon geothermochronology reveals pre-Alleghanian exhumation of regional Mississippian sediment sources in the southern Appalachian Valley and Ridge Province

<div>Figure 4 is interactive. Hover over each sample set (right) to see stacked on composition-age fields (left) (A) 250–500 Ma and (B) 800– 1200 Ma. Layers may be viewed separately or in combination using the capabilities of the Acrobat (PDF) layering function (click “Layers” icon along vertical bar on left side of window for display of available layers; turn layers on or off by clicking the box to the left of the layer name). Figure 5 is interactive. Hover over the Th/U>75 (black-red) box and Th/U<75 (green) box in the lower part of the figure to view subset KDEs of each sample. Layers may be viewed separately or in combination using the capabilities of the Acrobat (PDF) layering function (click “Layers” icon along vertical bar on left side of window for display of available layers; turn layers on or off by clicking the box to the left of the layer name).<br></div>

Supplemental Material: Detrital zircon geothermochronology reveals pre-Alleghanian exhumation of regional Mississippian sediment sources in the southern Appalachian Valley and Ridge Province

<div>Figure 4 is interactive. Hover over each sample set (right) to see stacked on composition-age fields (left) (A) 250–500 Ma and (B) 800– 1200 Ma. Layers may be viewed separately or in combination using the capabilities of the Acrobat (PDF) layering function (click “Layers” icon along vertical bar on left side of window for display of available layers; turn layers on or off by clicking the box to the left of the layer name). Figure 5 is interactive. Hover over the Th/U>75 (black-red) box and Th/U<75 (green) box in the lower part of the figure to view subset KDEs of each sample. Layers may be viewed separately or in combination using the capabilities of the Acrobat (PDF) layering function (click “Layers” icon along vertical bar on left side of window for display of available layers; turn layers on or off by clicking the box to the left of the layer name).<br></div>

Supplemental Material: Detrital zircon geothermochronology reveals pre-Alleghanian exhumation of regional Mississippian sediment sources in the southern Appalachian Valley and Ridge Province

<div>U-Pb zircon data, U-Th/He data, and HeFTy models.<br></div>

Supplemental Material: Detrital zircon geothermochronology reveals pre-Alleghanian exhumation of regional Mississippian sediment sources in the southern Appalachian Valley and Ridge Province

<div>U-Pb zircon data, U-Th/He data, and HeFTy models.<br></div>

Quantifying shortening across the central Appalachian fold-thrust belt, Virginia and West Virginia, USA: Reconciling grain-, outcrop-, and map-scale shortening

We present a kinematic model for the evolution of the central Appalachian fold-thrust belt (eastern United States) along a transect through the western flank of the Pennsylvania salient. New map and strain data are used to construct a balanced geologic cross section spanning 274 km from the western Great Valley of Virginia northwest across the Burning Spring anticline to the undeformed foreland of the Appalachian Plateau of West Virginia. Forty (40) oriented samples and measurements of &gt;300 joint orientations were collected from the Appalachian Plateau and Valley and Ridge province for grain-scale bulk finite strain analysis and paleo-stress reconstruction, respectively. The central Appalachian fold-thrust belt is characterized by a passive-roof duplex, and as such, the total shortening accommodated by the sequence above the roof thrust must equal the shortening accommodated within duplexes. Earlier attempts at balancing geologic cross sections through the central Appalachians have relied upon unquantified layer-parallel shortening (LPS) to reconcile the discrepancy in restored line lengths of the imbricated carbonate sequence and mainly folded cover strata. Independent measurement of grain-scale bulk finite strain on 40 oriented samples obtained along the transect yield a transect-wide average of 10% LPS with province-wide mean values of 12% and 9% LPS for the Appalachian Plateau and Valley and Ridge, respectively. These values are used to evaluate a balanced cross section, which shows a total shortening of 56 km (18%). Measured magnitudes of LPS are highly variable, as high as 17% in the Valley and Ridge and 23% on the Appalachian Plateau. In the Valley and Ridge province, the structures that accommodate shortening vary through the stratigraphic package. In the lower Paleozoic carbonate sequences, shortening is accommodated by fault repetition (duplexing) of stratigraphic layers. In the interval between the duplex (which repeats Cambrian through Upper Ordovician strata) and Middle Devonian and younger (Permian) strata that shortened through folding and LPS, there is a zone that is both folded and faulted. Across the Appalachian Plateau, slip is transferred from the Valley and Ridge passive-roof duplex to the Appalachian Plateau along the Wills Mountain thrust. This shortening is accommodated through faulting of Upper Ordovician to Lower Devonian strata and LPS and folding within the overlying Middle Devonian through Permian rocks. The significant difference between LPS strain (10%–12%) and cross section shortening estimates (18% shortening) highlights that shortening from major subsurface faults within the central Appalachians of West Virginia is not easily linked to shortening in surface folds. Depending on length scale over which the variability in LPS can be applied, LPS can accommodate 50% to 90% of the observed shortening; other mechanisms, such as outcrop-scale shortening, are required to balance the proposed model.

Common Spring Types in the Valley and Ridge Province: There Is More than Karst

ABSTRACT The Valley and Ridge Province (V&R) of the central Appalachians is rich in springs that support ecosystems, provide local water resources, and export water from the region. Although there has been extensive research on springs in the province, the focus has been on chemically variable karst springs. The purpose of this work is to identify common spring types found in the V&R based on an analysis of three regions. Three types of V&R springs are included in this comparison, and their relationship to more general classification systems is included. Headwater springs, located near ridge tops and along ridge flanks, are typically small, may be ephemeral, have localized flow paths, and are associated with siliciclastic units. Karst springs, generally located in the valleys, include both the more chemically variable limestone springs and the more stable dolomite springs. Thermal warm springs, with temperatures higher than the mean annual air temperature, are less common than the other spring types; they may be large and are typically associated with major thrust faults. The temperature, chemistry, and locations of the springs are controlled by the structural geology and topography as well as the formations and lithologies through which the recharge water travels. There is overlap in the water chemistry and storm responses of the spring groups, but some general trends can be identified, such as lower pH in the headwater springs. The V&R springs are critical resources, but their sustainability, chemistry, and hydrology need to be considered within the local geologic framework.

A new species of stygobitic snail in the genus Antrorbis Hershler & Thompson, 1990 (Gastropoda, Cochliopidae) from the Appalachian Valley and Ridge of eastern Tennessee, USA

A new species of cave snail (Littorinimorpha: Cochliopidae) in the genus Antrorbis is described from the dark zone of two caves in the Appalachian Valley and Ridge province in eastern Tennessee, United States. The Tennessee Cavesnail, Antrorbis tennesseensis Perez, Shoobs, Gladstone, &amp; Niemiller, sp. nov. is distinguished from its only known congener, Antrorbis breweri, by the absence of raised tubercles on its finely spirally striate protoconch, and its unique radular formula. Moreover, A. tennesseensis is genetically distinct from A. breweri based on substantial divergence at the mitochondrial CO1 locus. This is the first cavesnail to be described from the Appalachian Valley and Ridge (AVR) physiographic province in the state of Tennessee, which previously represented a substantial gap in the distribution of stygobitic (i.e., aquatic, subterranean-obligate) gastropods.