Arthur B. Busbey

Mapping micro-urban heat islands using LANDSAT TM and a GIS

Abstract LANDSAT TM satellite data and GIS software were used to map micro-urban heat islands in a portion of Dallas, Texas. Unsupervised classifications were performed on a LANDSAT subscene to extract tree cover information which was merged with TM band 6 data (thermal) to make a map showing the location of micro-urban heat islands and wooded areas. Results indicate the presence of micro-urban heat islands are resulting from the lack of tree cover related to newly developed residential neighborhoods, parking lots, business districts, apartment complexes, and shopping centers. All micro-urban heat islands were radiative in nature, with highest temperatures in the center.

Hydrocarbon potential of the Barnett Shale (Mississippian), Delaware Basin, west Texas and southeastern New Mexico

The Barnett Shale (Mississippian) in the Delaware Basin has the potential to be a prolific gas producer. The shale is organic rich and thermally mature over large parts of the basin. Depths to the Barnett range from 7000 ft (2133 m) along the western edge of the basin to more than 18,000 ft (5486 m) along the basin axis. The Barnett Shale began generating petroleum about 250 Ma and reached its maximum temperature about 260 Ma. Present-day thermal maturity is indicative of maximum burial and temperature. Wells in northern Reeves County are in the gas window based on measured vitrinite reflectance values and kerogen transformation ratios. The shale can be divided into an upper clastic unit and a lower limy unit by changes in resistivity. The lower unit can be subdivided into five subunits by distinctive well-log markers. Preliminary analyses suggest that intervals in the lower Barnett marked by high resistivity and high neutron porosity readings on well logs have high gas contents. Areas in which to focus the future exploration in the lower Barnett can be delineated by mapping a net resistivity greater than 50 ohm m. The Barnett Shale contains significant gas resources in the Delaware Basin. Realizing the potential of these resources depends on the current efforts to optimize drilling and completion techniques for this shale-gas play.

New material of Sebecus cf. huilensis (Crocodilia: Sebecosuchidae) from the Miocene La Venta Formation of Colombia

ABSTRACT Sebecus huilensis, an advanced sebecosuchian crocodilian, was first described by Langston (1965) based on a fragmentary lower jaw from the Miocene La Venta Formation of Colombia. New skeletal fragments from the same unit are referable to S. cf. huilensis and add to our knowledge of sebecosuchian cranial and postcranial anatomy. These fragments indicate that the skull was more laterally compressed than that of the Eocene S. icaeorhinus (based on comparison with the type of the latter). S. cf. huilensis is the first sebecosuchian for which a complete retroarticular process is known. The posterior portion of the retroarticular process is unlike that of any known crocodilian, with a ventral deflection of the medial edge, indicating significant changes in muscle size. A single, unusual osteoscute also may be referred to this animal, suggesting that sebecosuchians had some dermal osteoscutes. Comparison with the type of S. huilensis also suggests that Buffetaut and Hoffstetter (1977) may have been in e...

Possible new evidence for the origin of metazoans prior to 1 Ga: Sediment-filled tubes from the Mesoproterozoic Allamoore Formation, Trans-Pecos Texas

Possible new evidence for the origin of metazoans prior to 1 Ga comes from sediment-filled tubes preserved on a bedding-plane parting in a chert in the Allamoore Formation (Mesoproterozoic) in a talc quarry in the Millican Hills, near Van Horn, Trans-Pecos Texas. Available data for the Van Horn region indicate that the age of the Allamoore Formation is ∼1250 Ma. The sediment-filled tubes are most likely the feeding traces of animals grazing on algal mats in shallow subtidal or intertidal environments.

Using spot satellite data to map impervious cover for urban runoff predictions

Environment planners are constantly seeking rapid, accurate, and cost‐effective techniques to determine land cover information associated with water quality and quantity during runoff events in urban watersheds. Traditionally, this is accomplished with field surveys, aerial photographs, and/or generalized published maps. These techniques can be time consuming and labor intensive. In this study, SPOT, 10 meter‐panchromatic, satellite digital data were used to classify and map impervious cover in an urban watershed in Dallas, Texas (USA). Using the image‐derived impervious cover map and a hydrologic runoff equation, urban storm water volumes were predicted for 1990 and 1991 with an 85% accuracy when compared to actual runoff data obtained from a U.S. Geological Survey (U.S.G.S) stream gauge station.

Evidence for Late Cretaceous Volcanism in Trans‐Pecos Texas

Cretaceous basaltic pyroclastic strata have been discovered in a fault block on the southern edge of the Rosillos Mountains laccolith in the Big Bend area of Trans‐Pecos Texas. The sequence comprises base‐surge and pyroclastic‐fall deposits inferred to have accumulated on the flanks of a small phreatomagmatic volcano. A diverse assemblage of freshwater turtles (including Aspideretes), crocodile teeth, and dinosaur bones have been recovered from the uppermost part of the sequence. The fauna indicate a Late Cretaceous, probably Campanian age. An outward‐dipping normal fault bounding the pyroclastic strata on the southeast juxtaposes sediments of the Upper Cretaceous Javelina Formation in the hanging wall with pyroclastic rocks in the footwall, indicating the pyroclastic strata must be Maastrichtian or older. U‐Pb SHRIMP‐RG analyses of zircons separated from a basaltic block thrown out of the volcano yield an inferred igneous crystallization age of \documentclass{aastex} \usepackage{amsbsy} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{bm} \usepackage{mathrsfs} \usepackage{pifont} \usepackage{stmaryrd} \usepackage{textcomp} \usepackage{portland,xspace} \usepackage{amsmath,amsxtra} \usepackage[OT2,OT1]{fontenc} \newcommand\cyr{ \renewcommand\rmdefault{wncyr} \renewcommand\sfdefault{wncyss} \renewcommand\encodingdefault{OT2} \normalfont \selectfont} \DeclareTextFontCommand{\textcyr}{\cyr} \pagestyle{empty} \DeclareMathSizes{10}{9}{7}{6} \begin{document} \landscape

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U–Pb detrital zircon geochronology and Hf isotopic composition of Permian clastic rocks, Zhen’an basin, South Qinling belt: implications for the Paleozoic tectonic evolution of the Qinling orogenic belt

\end{document} Ma, consistent with the biostratigraphic and structural evidence. The pyroclastic strata in the fault block provide the first evidence for Late Cretaceous volcanism in the Trans‐Pecos region. Previously, the onset of igneous activity in the area was thought to be no older than 64 Ma. We speculate that the basaltic pyroclastic rocks represent an extension of the Upper Cretaceous Balcones magmatic province into Trans‐Pecos Texas.