An application of the Hypothesis of Punctuated Aggradational Cycles to the Upper Silurian-Lower Devonian carbonate sequence (Tonoloway and Keyser formations) at seven localities in central Pennsylvania reveals that the interval is entirely divisible into as many as 22 PACs which are correlative throughout the study area. Of these 22 PACs, 5 groups of PACs of similar facies are recognized in the interval. These groups of PACs are initiated and terminated by major deepening events which produce the primary surfaces of correlation in the interval. Paleoenvironments develop episodically throughout the interval, each punctuation event initiating and terminating a unique spectrum of small-scale environments. The Tonoloway portion of the interval represents a sequence of tidal-flat PACs. The transition to the shelf environments of the Lower Keyser Formation occurs episodically through 2 PACs consisting of nearshore, subtidal facies. The Upper Keyser is a shallowing sequence of PACs representing the episodic return from shelf to tidal-flat facies. Correlations reveal that as much as 13.5 meters of stratigraphic section, representing seven PACs, is missing at the Tonoloway-Keyser formation boundary at Tyrone, Pennsylvania. This missing section is interpreted to be the result of non-deposition because of differential uplift to the north of a proposed crustal-block boundary, represented by the Tyrone-Mt. Union lineament, while the basin to the south was differentially subsiding and PACs 1-7 were being deposited. Recognition of two paleoisotopographic surfaces (sea-level surfaces) at the base of PAC 1 and the top of PAC 22 facilitates the discernment of 17.5 meters of stratigraphic thickness difference attributable to differential subsidence between Tyrone and Cessna, Pennsylvania. / Earth and Environmental Science / Accompanied by one .pdf file: 1) Goodman-Supplemental-1986.pdf

The Triassic Brunswick Formation is an important aquifer in south­eastern Pennsylvania and northern and central New Jersey, an area where rapid development is producing increased groundwater use. In order to prevent groundwater mining, it is necessary to have knowledge of the rate of groundwater recharge. Based on streamflow data during periods of baseflow recession, Moody and Associates, Inc. (1975) estimated the average annual recharge rate for the Brunswick Formation to be between 300,000 and 400,000 gallons/day/square mile. In this study the groundwater recharge rate for the Brunswick Forma­tion was calculated by the baseflow recession and hydrologic budget methods using streamflow and climatic data from three small water­sheds. The baseflow recession method yielded annual groundwater recharge rates which ranged from 441,000 gallons/day/square mile to 663,000 gallons/day/square mile. Annual groundwater recharge rates calculated using the hydrologic budget method ranged from 321,000 gallons/day/square mile to 424,000 gallons/day/square mile. Based on the results of both methods, the average annual recharge rate is 447,000 gallons/day/square mile. Although the baseflow recession method yielded reasonable annual recharge rates, it does not produce accurate results for shorter time periods. Monthly groundwater recharge rates calculated using the hydrologic budget are much more representative of actual seasonal variations than those calculated using the baseflow recession method. The primary advantage of the baseflow recession method is that it is simpler to use and requires much less data. The results of this study illustrate that groundwater recharge is controlled by both the hydraulic characteristics of the aquifer and climatic conditions. During the winter months, when there is a precipitation excess, the hydraulic characteristics of the aquifer determine the maximum potential recharge rate. However, during the summer months when there is less precipitation and greater evapotranspiration, the maximum potential recharge rate is not attained. / Earth and Environmental Science / Accompanied by one .pdf file: 1) Sacks-Supplemental-1986.pdf

The determination of the aquifer parameters of transmissivity and storativity from pump test data of a two layer confined aquifer system is not possible due to the indeterminacy of the discharge from each aquifer to the pumping well bore. To resolve this theoretical problem and analyze pump test data from a groundwater system in the Triassic Brunswick Formation of northeastern Montgomery County, Pennsylvania, the Darcy Weisbach model of turbulent flow in pipes or conduits was coupled with the Theis model of confined aquifer flow to produce a mathematical model that simulates the distribution of discharge within a pumping well bore and the accompanying distribution of hydraulic head throughout the two aquifer layers. Two analytic models and one finite difference model were developed, tested and applied to the analysis of the study area pump test data. Analysis of the models showed that approximations of the transmissivities of the two aquifer layers could be determined from pump test data via a method similar to the Jacob straight line method. The models demonstrated that the distribution of discharge between the two aquifer layers is a variable function of time, that the change in the distribution of discharge over time is small in reference to the initial distribution and decreases in magnitude over time. Model simulation runs based on the transmissivity (T) calculation and a range of storativities (S) and boundary conditions yielded a good fit to pump test drawdown data for lower aquifer layer values of 4900 gal/ft/day (T) and 5.SE-6 (S) and upper aquifer layer values of 400 gal/ft/day (T) and lE-4 (S), plus a single barrier boundary in the lower aquifer located 2500 feet updip from the pumping well. The simulation results provide theoretical evidence in support of the interpretation of the study area groundwater system as a two layer system. The models demonstrated theoretically that two layer aquifer systems can produce distributions of drawdown data in observation wells that appear to evidence non-Theisian conditions, though in fact the individual layers are Theisian aquifers. As such, pump test data from Triassic Brunswick aquifers that exhibit non-Theisian distributions of drawdown may result from the distribution of pump discharge within the pumping well bore to vertically separated Theisian aquifer layers. / Earth and Environmental Science

The redox states of phases in primitive meteorites provide constraints for the composition of the early nebu­lar gas in which the planets and asteroids formed. The bulk composition nebula from solar spectra abundances and equilibrium condensation theory predicts that oxygen was bound up in CO at high temperatures so that the H2/H20 ratios of the early solar nebula were high (100-2000) and thus the nebular gas was very reducing. Equilibrium calcu­lations and experimental extrapolations of fO2-composition equilibria for primitive, Ca, Al-rich inclusion (CAI) and chondrule phases in the Allende CV3 carbonaceous chondrite show a range of oxidation states, with fassaite, a Ti-rich clinopyroxene, possibly equilibrating with the inferred reduced nebular gas while other phases and components equilibrated with more oxidized gases, 1 to 4 orders of magnitude more oxidized than the inferred, reduced nebular gas. Intrinsic oxygen fugacity (IOF) measurements using the double-cell, solid electrolyte technique developed by Sato (1971) and modified by Ulmer et al., (1976) were taken for whole rock samples of one olivine porphyry and two CAI in the Allende meteorite at temperatures of 800°to 1150° C. Results show their oxidation states to be 5-8 orders of magnitude more oxidized than the inferred nebu­lar gas at these temperatures. Melilite separates from the two CAI gave IOF measurements 8-10 orders of magnitude more oxidized than the calculated, reduced nebular gas and act as a strong oxidation buffer to the redox state of Ti3+-rich fassaite in the whole rock samples. The high oxidation state of melilite is due to its equilibration at high temperatures (>700°C) with a relatively oxidized gas and is also due to its high oxygen exchange and diffusion rates (Hayashi and Muelenbachs, 1986). IOF measurements of fine-grained alteration mineral clumps in one CAI yield an oxidation state more oxidized than the whole rock CAI IOF but more reduced than melilite from the same CAI. IOF measurements show that melilite and alteration minerals are in disequilibrium with respect to fO2 yet these phases are close to equilibrium with respect to oxygen isotope composition. CAI alteration minerals have cores of a Ti­rich phase which is reduced and inferred to be fassaite. IOF experiment results indicate either heterogeneity in the composition of the nebula across time and/or space or disequilibrium between primitive material and the nebu­lar gas. / Earth and Environmental Science

Application of the PAC Hypothesis to the deep shelf carbonate facies of the lower New Scotland Formation (Lower Devonian) results in the complete division of this interval into IO PACs that may be correlated throughout the Hudson Valley of Eastern New York State. These deep water PACs primarily consist of terrigenous black shale alternating with limestone beds, the black shale being concentrated at the bases of PACs. Sedimentological analysis suggests that the shales represent "background" deposition of fine suspended sediment and the limestones are event deposits, possibly turbidites and/or tempestites. In contrast to PACs recognized in much shallower facies, a shallowing-upward motif is absent in lower New Scotland PACs. The absence of a shallowing facies pattern suggests that abrupt base-level rises had little direct depth related impact on the deep lower New Scotland shelf. Instead facies change within these PACs was an indirect response related to the supply of transported carbonate sediment into the deep shelf. Comparative analysis of the magnitude of facies change at the base of each lower New Scotland PAC indicates that the sequence of PACs in the study interval is the result of 1 major punctuation event followed by 10 minor punctuation events. General vertical patterns of facies change from PAC to PAC suggest that the deepest point in the lower New Scotland is reached at the base of PAC 7. Lateral facies analysis within PACs leads to the recognition of a proximal to distal trend from Kingston to Callanan Quarry (south to north), a distance of approximately 50 miles. Lower New Scotland PACs at Kingston are characterized by relatively shallower facies, while at Callanan Quarry, these PACs are characterized by deeper, more basinal facies. The lateral persistence of the 10 New Scotland deep water PACs over 50 miles precludes an autogenic origin of these cycles. Rather, accumulation of the deep shelf facies of the lower New Scotland, like the shallower facies of the Kalkberg, Coeymans, and Manlius Formations was principally controlled by small-scale base-level fluctuations as predicted by the PAC hypothesis. / Earth and Environmental Science / Accompanied by one .pdf file: 1) Side-Supplemental-1987.pdf

A long, narrow, straight belt of closely spaced Bouguer gravity contours and lithologic boundaries coincides with the Martic shear zone, southeastern Pennsylvania. The most likely cause of the steep gravity gradient is sought by checking the influence of the density of surface lithologies, mass distribution associated with the topography, and the isostacy model. 15-20 km difference in crustal thickness across the Martic Zone is calculated using Sharma's data and maximum depth equation. Based on a shear zone geometry, gravity anomaly parallelism, and crustal thickness contrast, the Martic Zone is proposed to be the western boundary of the Piedmont terrane. The Martic Zone is compared with other areas such as the San Andreas Fault and the Alpine Fault to evaluate possible plate boundary features. This tectonic interpretation of the Martic Zone may contribute to a new view on the central Appalachian orogenic belt. / Earth and Environmental Science

Basalt from the Cohassett flow of the Columbia River Basalt Group (Southeast Washington) was reacted with synthetic Hanford groundwater in Dickson rocking autoclaves at 200° and 300°C, 30 MPa, with initial water:rock mass ratios of 50. During the experiments fresh solutions were re-injected into the reaction cells using a high-pressure chromatography pump. The re-injection experiments are intermediate between closed-system Dickson experiments and flow-through tests in that the fluid and solids can remain in contact for extended periods of time before the solution is replaced. This allows more time for equilibrium to be approached. Data from these experiments suggest the following interpretations: (1) After re-injection many solution parameters quickly (hrs-days) return to near pre-injection values. (2) The redox buffer capacity of the basalt was not exceeded, i.e. fO2 values remained near magnetite-hematite, although nominal water:rock mass ratios as high as ca. 140 were achieved by re-injection. (3) After re-injection the stable high-temperature pH value was only slightly less than the initial pH value, particularly at 300°C. (4) The silica concentration stabilized near apparent quartz saturation in one 300°C experiment, rather than the cristobalite saturation value found in closed-system experiments. (5) Ca­Na-K, quartz, and alpha-cristobalite geothermometer values from the re-injection experiments more closely model the actual experiment temperature than do values from closed­ system Dickson experiments. (6) Short-term relationships between cations appeared to be controlled by ion-exchange between the solutions and secondary clay minerals. Reaction products identified from the re-injection experiments include: Fe-smectite, illite, hematite, very minor cristobalite and possibly Ti-maghemite at 300°C, plus K-spar and analcime in 200°C and variable temperature (300° to 200°C) experiments. / Earth and Environmental Science / Accompanied by one .pdf file: 1) Gardiner-Supplemental-1988.pdf

The hydrothermal stability of copper has been studied to assess its suitability as a container material for disposal of nuclear waste in the proposed repository site at Hanford, Wa. The experiments were conducted using titanium reaction cells at 200° and 300°C, 30 MPa, using Dickson rocking autoclaves for up to 3000 hours. Three of the experiments contained a quartz normative Columbia River Basalt (RCE-3), synthetic low salinity groundwater (ca. 400 mg/L Cl-), and "purified" copper powder. The results of these experiments prompted a fourth to determine the suitability of titanium as a reaction cell. The results of the copper bearing experiments suggest that: (1) the use of copper as a container material would not significantly alter basalt-water reactions in the short term; (2) care should be taken to minimize oxygen contamination of the copper as this could adversely affect the redox conditions in the repository; (3) copper does not appear to affect the solution pH although any small changes would have been masked by reactions with the titanium reaction cell. The data from the titanium cell experiment showed significant differences (in comparison to similar previous gold cell experiments) in calculated high temperature pH values and dissolved sulfide concentrations; chloride concentrations were also slightly different. The results of this experiment suggest that titanium is not inert and should probably not be used in experiments containing low ionic strength solutions. / Earth and Environmental Science

Re-examination of the Rosemont Fault (southeast Pennsylvania Piedmont) using the ductile shear zone approach reveals a large (1.5-3.0 km wise) ductile shear zone. The Rosemont shear zone strikes parallel to the Rosemont fault line (N30-40°E) and is moderate to steeply dipping. Numerous perpendicular transects across the Rosemont zone reveal a complex geometry. Unlike a classic tabular-shaped shear zone the boundaries of the Rosemont zone are not parallel. The eastern boundary strikes approximately N35°E and is very steeply dipping (70-90°E) while the western boundary has a similar strike but a variable dip between 40-60°E. In cross-section the Rosemont zone has a semi-wedge shape that widens in the upward direction. The variability i the horizontal width of the zone as well as the orientations of the boundaries are most likely the result of large competency difference between different lithologies associated with the Rosemont zone. Consistent dextral shear sense was determined using 1) asymmetric tails around porphyroclasts in thin-section, 2) numerous small (meter scale) parasitic shear zones with obvious right lateral displacement, and 3) dextral transposition of earlier structures into the zone as seen on the regional scale. Correlation of a sliver of mafic gneiss with the Wilmington Complex supports a model of dextral displacement with a minimum offset of 20 kilometers. Six phases of deformation were recognized. The first phase was a postulated overthrusting of the Wilmington Complex onto the Wissahickon Group. This thrusting event was followed by four phases of transcurrent ductile shearing and finally a weak phase of reverse ductile displacement possibly as a result of uplift. Retrodeformation of the largest ductile structures (phase 5: Martic zone; phase 3: Rosemont zone) suggests that the Baltimore Gneiss was once adjacent to the Wilmington Complex. / Earth and Environmental Science / Accompanied by one .pdf file: 1) Valentino-Supplemental-1988.pdf

Over one hundred and fifty basanite features are located in a 12.1 square kilometer (4.73 square mile) area on the north rim of the Grand Canyon National Monument, at the southern edge of the Toroweap Valley. Thirty-six of these were analyzed to determine their origin. The features, previously described as "Pressure blisters" (Hamblin and Best, 1970), are believed to be direct mantle orifices that have erupted under an ash or lava cover. Green and red colored peridotite xenoliths of varying dimensions are found enclosed within these features on the Toroweap Valley as well as on the adjacent cinder cone Vulcan's Throne. The unique red coloring, observed primarily in forsteritic olivine (Fo90-92), is believed to be a result of precipitation of a ferric rich phase within individual olivine grains. Results obtained from a theoretical single-pyroxene geothermobarometer (Mercier, 1980) suggest pressures of at least 15 kilobars and temperatures of at least 940°C, corresponding to a depth of origin of at least 52 kilometers for the Toroweap Valley features. A genetic model developed suggests that the basanite lava carrying green colored olivine originated from a magma chamber at least 52 kilometers below the ground surface, transected a shallower magma chamber in which red colored xenoliths are suspended and punctured the crust in the Toroweap Valley. / Earth and Environmental Science