Detailed field and petrographic study of the Precambrian Rough Ridge Formation of the Packsaddle Schist documents a more complex tectonic history for the Llano Uplift than has previously been reported. The Rough Ridge Formation was affected by two metamorphic events and four phases of deformation. Mineral assemblages in pelitic and mafic lithologies are characteristic of the amphibolite facies, and the presence of cordierite in preference to almandine indicate low pressure during part of the metamorphism. Inclusions of staurolite in a Mn-rich garnet, coupled with the absence of staurolite elsewhere in the rock suggest that pressure may have ranged from medium to low during metamorphism. Textures indicate that post-tectonic recrystallization occurred as a consequence of either slow cooling or of reheating after dynamothermal events. The first phase of deformation (D1) was a complete transposition of original sedimentary layers, with a pervasive foliation (S1) forming parallel to the axial planes of isoclinal folds. D2 is characterized by small folds and a crenulation cleavage S2. D3 formed a crenulation cleavage S3. D4 formed the prominent folds in the area, with a pervasive axial planar cleavage S4. Isolated occurrences of a pre-S1 metamorphic foliation are evidence of still earlier deformation. In one pelitic unit, oriented inclusions show that garnet growth was post-D2, while cordierite growth was post-D4. Growth and recrystallization of micas, quartz and feldspar span all the deformations. The timing of deformation events is bracketed by the pre- to syn-tectonic intrusion of the 1167 +/- 15 m.y. old Red Mountain Gneiss, and the post-tectonic intrusion of a 1080 +/- 15 m.y. old melarhyolite dike. The results of this study demonstrate that rocks of the Llano Uplift have undergone a complex tectonic and metamorphic history similar to that seen in other Grenville Age rocks of North America. / text

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Hydrocarbon producing, deep-water Cisco sands along the Eastern Shelf were studied in the vicinity of Flowers "Canyon Sand" Field to develop a depositonal model explaining their origin, geometry, and style of deposition. Regional correlations and subsurface mapping indicate that producing sands were deposited within the Swastika lithogenetic unit, which contains a network of shelf-margin fluvial/deltaic, slope, and basin depositional systems deposited between transgressive Gunsight and Ivan Limestones. The sands are not "Canyon", but Virgilian in age. During Swastika time a wedge of sediments up to 1100 feet thick was deposited in the study area in response to westward progradation of shelf-margin deltas. Standard mapping techniques and detailed correlations using nearly 700 well logs and the examination of 3 cores indicate that this wedge can be divided into three principal systems: (1) a sand-dominated turbidite, basin and lower slope system, which constitutes the reservoir facies, (2) a shale-rich prodelta/slope system punctuated by slope channel filled gullies, and (3) a sand-dominated shelf-margin fluvial/deltaic system. Ten deltaic lobes, averaging 2 miles in diameter, were recognized. These lobes may have been deposited during a lowstand of sea level. Elongate/lobate geometry and rapid shifting of lobes indicate high depositional rates. Shelf-margin instabilities associated with deltas led to prodelta/slope slumping, gully formation, and generation of turbidity currents. Turbidity currents generated by the earliest deltas to breach the shelf break were of sufficient magnitude to erode a broad, shallow inner-fan valley at the base of the slope. This valley initially focused turbidity currrents onto a base-of-slope terrace, which was mapped on top of the Gunsight Limestone, and formed by differential compaction over a subjacent Canyon delta or carbonate buildup. Low gradients associated with this terrace gave rise to a sediment trap. Nearly all existing production in Flowers Field is established above this terrace. Turbidites deposited within this phase of Swastika evolution display characteristics of an elongate/radial type fan deposit. Continued deltaic progradation filled the inner-fan valley. Once this valley was breached, a network of small channels originating as gullies along slopes in front of the advancing Swastika delta system transported sediment down the slope to form an aggrading/prograding wedge of turbidite and volumetrically less significant grain flow deposits. This change in depositional style led to superposition of what is best classified as an elongate/debris apron type system over the earlier elongate/radial deposits. A critical conclusion is that no single channel developed into a large canyon feeder system, which resulted in facies relationships that differ from commonly accepted models calling on a prolonged point source. Given the importance of turbidite sands in many petroliferous basins, application of the delta-fed model to appropriate turbidite systems can improve exploration strategies. / text

This paper presents a zonation of the Austin chalk and the Burditt marl, divisions of the Austin group in the Jonah quadrangle, Williamson County, Texas. The Austin chalk consists of the Inoceramus subquadratus Schlüter faunizone, Gryphaea wratheri Stephenson faunizone, Inoceramus undulatoplicatus Roemer faunizone, Hemiaster texanus Roemer faunizone, Exogyra laeviuscula Roemer faunizone, and the Exogyra tigrina Stephenson epibole. The Burditt marl contains the Ostrea centerensis Stephenson faunizone. The Austin-Taylor contact has been traced from the southeastern to the northeastern corner of the area. The relations of the Taylor marl and some of the Terrace gravels are discussed. The outcrop, lithology, and paleontology of the Eagle Ford shale, which underlies the Austin group, are also included. / text

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In the last few years, the City of Dallas has witnessed a substantial increase in the level of citizen participation in land-use decisions. A little known provision of the Texas Civil Statutes allows cities to divide their town into 'Neighborhood Zoning Areas' to provide another method for citizen review of zoning applications. The purpose of this thesis is to examine present methods for soliciting citizen comments, examine the quality of land-use decisions and to determine successes and failures 'Neighborhood Councils' have had in three other cities.The literature concerning present neighborhood involvement in the zoning appeals process is sketchy and somewhat contradictory. Therefore, the experience of Portland, Oregon; Dayton, Ohio; and Washington, D.C. was analyzed to determine how well subordinate governmental units function in other cities. The information received in the case studies was limited due to several factors, but all three city staffs gave hearty endorsement to their particular systems. No negative consequences of using this particular system was noted.A review of Plan Commission voting records revealed that the quality of land-use decisions made through the zoning appeals process needs to be improved.Citizen attitudes were examined to determine whether a neighborhood advisory council would increase citizen input or merely interject an anti-development bias into the zoning appeals process. Three neighborhood representatives were interviewed and all demonstrated that they were capable of negotiating and possessed a good perspective of neighborhood planning issues. Creation of neighborhood advisory councils would possibly correct the existing imbalance between developer interests and neighborhood interests.Whether neighborhood advisory councils will ever be initiated in Dallas is difficult to predict. One recent City Council recommendation directed the staff to explore ways to encourage negotiations between neighborhoods and developers. A proposal to form neighborhood advisory councils could grow out of this recommendation. / Department of Urban Planning