Stephen A. Kish

Fault-related rocks: Suggestions for terminology

Many traditional terms for fault-related rocks have undergone recent dynamic metamorphism under high-pressure discussions by various groups of specialists. A generally acceptable simplified framework encompassing these and associated structural terms is now needed for many geologic, engineering, and legal purposes. Such a framework is proposed here, focusing on a rate-of-strain versus rate-of-recovery diagram and relating this framework to the products of brittle and ductile deformation along faults.

Laboratory analog and numerical study of groundwater flow and solute transport in a karst aquifer with conduit and matrix domains.

New mathematical and laboratory methods have been developed for simulating groundwater flow and solute transport in karst aquifers having conduits imbedded in a porous medium, such as limestone. The Stokes equations are used to model the flow in the conduits and the Darcy equation is used for the flow in the matrix. The Beavers-Joseph interface boundary conditions are adopted to describe the flow exchange at the interface boundary between the two domains. A laboratory analog is used to simulate the conduit and matrix domains of a karst aquifer. The conduit domain is located at the bottom of the transparent plexiglas laboratory analog and glass beads occupy the remaining space to represent the matrix domain. Water flows into and out of the two domains separately and each has its own supply and outflow reservoirs. Water and solute are exchanged through an interface between the two domains. Pressure transducers located within the matrix and conduit domains of the analog provide data that is processed and stored in digital format. Dye tracing experiments are recorded using time-lapse imaging. The data and images produced are analyzed by a spatial analysis program. The experiments provide not only hydraulic head distribution but also capture solute front images and mass exchange measurements between the conduit and matrix domains. In the experiment, we measure and record pressures, and quantify flow rates and solute transport. The results present a plausible argument that laboratory analogs can characterize groundwater water flow, solute transport, and mass exchange between the conduit and matrix domains in a karst aquifer. The analog validates the predictions of a numerical model and demonstrates the need of laboratory analogs to provide verification of proposed theories and the calibration of mathematical models.

Coastal Response to Storms and Sea-Level Rise: Santa Rosa Island, Northwest Florida, U.S.A.

ABSTRACT Kish, S.A. and Donoghue, J.F., 2013. Coastal response to storms and sea-level rise: Santa Rosa Island, northwest Florida, U.S.A.. In: Brock, J.C.; Barras, J.A., and Williams, S.J. (eds.), Understanding and Predicting Change in the Coastal Ecosystems of the Northern Gulf of Mexico, Journal of Coastal Research, Special Issue No. 63, pp. 131–140, Coconut Creek (Florida), ISSN 0749-0208. The western panhandle coast of northwest Florida is wave dominated and microtidal. Major storms are infrequent but have a significant effect on coastal morphology. Santa Rosa Island, a 75-kilometer long barrier, is the major coastal feature of the region. The island is narrow, with an average width of 500 meters. During most of the historical period, prominent foredunes, ranging as high as 7 meters, have helped keep the islands sediment budget in near equilibrium. This investigation compiled and georeferenced nearly two dozen historical shoreline positions from surveys and aerial photos, dating from the 1850s to the present. Time intervals between shoreline positions ranged from 30 years to multiple datasets per year. The U.S. Geological Surveys Digital Shoreline Analysis System (DSAS) was used to analyze the shoreline data. Analysis of the dataset reveals that storms have heavily influenced shoreline position. Shoreline retreat during the period from 1851—present has averaged less than 1 meter per year. Periods of more rapid retreat have been associated with the occurrence of major storms. A six-decade period of relative quiescence during the mid-20th century resulted in modest advance of the islands coastline. A cluster of three major storms during the period 1995–2005 had a major impact on the morphology and stability of the island. Much of the foredune complex was lost and rates of coastal retreat increased significantly. The historical shoreline data therefore underscore the dominant influence of storm frequency and intensity in determining coastal change.

Laurentian magmatism of the southern Appalachian Blue Ridge: Post-Iapetan rifting

Tectonically significant postrift metaigneous rocks occur within three genetically distinct cover-rock sequences along a 400 km strike segment of the southeastern margin of Laurentia, in the southern Appalachian western Blue Ridge. These include (1) Neoproterozoic rift facies rocks, (2) lower Paleozoic drift facies rocks, and (3) unconformably overlying postdrift Paleozoic successor basin sequences. This region is divisible into two along-strike, ensialic, continental margin volcanic belts, separated by a probable Neoproterozoic transfer fault. To the northeast, igneous rocks are intrusive into sequences 1 and 2 above, whereas in the overlying successor basins on both sides of the transfer boundary, they occur predominantly as eruptive rocks. These igneous rocks can be separated into several suites that are distinct from the Neoproterozoic rift-related igneous rocks, based on stratigraphic position, geographic location, and composition. Mafic dikes and sills intrusive into the rift facies and mafic metavolcanic rocks of the Hillabee Greenstone represent low-K tholeiitic magmatism associated with derivation from a “depleted” mantle source, whereas most igneous rocks in the northeastern belt exhibit an alkaline basalt affinity. The successor basin sequences associated with the volcanic activity formed above extended and thinned continental crust, near and parallel to the southeastern Laurentian margin. This igneous activity can be constrained broadly between stratigraphic position and age of metamorphism (Middle Ordovician to earliest Mississippian time). Most likely this magmatic activity was associated with a destructive plate boundary during Paleozoic A-type subduction, but was largely decoupled from slab-derived magmatism, being instead more likely associated with backarc or pull-apart basin evolution.

The Significance of Rb-Sr Glauconite Ages, Bonneterre Formation, Missouri; Late Devonian-Early Mississippian Brine Migration in the Midcontinent

Rb-Sr mean model ages of

Spatio-temporal analysis of decadal-scale patterns in barrier island response to storms: Perdido Key, NW Florida

370 \pm 10 Ma

Deformed Hercynian granitic rocks from the Piedmont of South Carolina

for glauconites from the Cambrian lower Bonneterre Formation in southern and central Missouri (in contrast to mean model ages of