Earth Sciences Commons^™

Comment On “Timing Of Mantle Upwelling: Evidence For A Passive Origin For The Red Sea Rift” By A. V. Mcguire And R. G. Bohannon, Timothy H. Dixon

School of Geosciences Faculty and Staff Publications

No abstract provided.

The Effect Of Tracking Network Configuration On Gps Baseline Estimates For The Casa Uno Experiment, S. Kornreich Wolf, Timothy H. Dixon, J. T. Freymuller

School of Geosciences Faculty and Staff Publications

Geodetic monitoring of subduction of the Nazca and Cocos plates is a goal of the CASA (Central and South America) Global Positioning System (GPS) experiments, and requires measurement of intersite distances (baselines) in excess of 500 km. The major error source in these measurements is the uncertainty in the position of the GPS satellites at the time of observation. A key aspect of the first CASA experiment, CASA Uno, was the initiation of a global network of tracking stations to minimize these errors. We studied the effect of using various subsets of this global tracking network on long (>100 …

First Gps Baseline Results From The North Andes, James N. Knellogg, Jeffrey T. Freymuller, Timothy H. Dixon, Ruth E. Neilan, Ropain U. Clemente, M. Camargo Sergio, Fernandez Ch. Benjamin, James L. Stowell, Anibal Salazai, Mora V. Jaime, Luis Espin, Vernon Perdue, Leonard Leos

School of Geosciences Faculty and Staff Publications

The CASA UNO GPS (Global Positioning System) experiment (January-February 1988) has provided the first epoch baseline measurements for the study of plate motions and crustal deformation in and around the North Andes. Two dimensional horizontal baseline repeatabilities are as good as 5 parts in 10⁸ for short baselines (100–1000 km), and better than 3 parts in 10⁸ for long baselines (>1000 km). Vertical repeatabilities are typically 4–6 cm, with a weak dependence on baseline length. The expected rate of plate convergence across the Colombia Trench is 6–8 cm/yr, which should be detectable by the repeat experiment planned …

Central And South America Gps Geodesy - Casa Uno, James N. Kellog, Tim Dixon

School of Geosciences Faculty and Staff Publications

In January 1988, scientists from over 25 organizations in 13 countries and territories cooperated in the largest Global Positioning System (GPS) campaign in the world to date (Table 1). 43 GPS receivers collected approximately 590 station-days of data in American Samoa, Australia, Canada, Colombia, Costa Rica, Ecuador, New Zealand, Norway, Panama, Sweden, United States, West Germany, and Venezuela. The experiment was entitled CASA UNO, an acronym for Central and South America – and uno is the Spanish word for one, designating first epoch measurements. The CASA UNO experiment was the first civilian effort implementing a global GPS satellite tracking network. …

Some Tests Of Wet Tropospheric Calibration For The Casa Uno Global Positioning System Experiment, Timothy H. Dixon, S. Kornreich Wolf

School of Geosciences Faculty and Staff Publications

Wet tropospheric path delay can be a major error source for Global Positioning System (GPS) geodetic experiments. We investigate strategies for minimizing this error using data from CASA Uno, the first major GPS experiment in Central and South America, where wet path delays may be both high and variable. We compared wet path delay calibration using water vapor radiometers (WVRs) and residual delay estimation, with strategies where the entire wet path delay is estimated stochastically without prior calibration, using data from a 270 km test baseline in Costa Rica. Both approaches yield centimeter-level baseline repeatability and similar tropospheric estimates, suggesting …

A Study For The Improvement, Restoration, And Protection Of Mill Pond, William B. Eviston, Thomas Crisman, Eric P. Ellingson

School of Geosciences Faculty and Staff Publications

No abstract provided.

Rupture Process Of The Macquarie Ridge Earthquake Of May 23, 1989, Jochen Braunmiller, John Nábělek

School of Geosciences Faculty and Staff Publications

Broadband body waves recorded at 15 digital seismic stations worldwide are used to study the rupture process of the May 23, 1989 Macquarie Ridge earthquake. The centroidal solution (strike 211°, dip 86°, rake 180°, and depth of 10 km below the seafloor) indicates shallow rupture with pure right-lateral strike-slip motion along the Pacific-Australia plate boundary, in agreement with motion predicted by plate tectonic models. The total seismic moment is 13.4×10²⁰ Nm, 80% of which was released in the first 24 s of the rupture process. Modeling favors a bilaterally propagating rupture with slightly different dip and rake for the …

Laboratory Studies Of Predatory Behaviour In Two Subspecies Of The Carabid Cave Beetle: Neaphaenops Tellkampfi, David M. Griffith

International Journal of Speleology

Comparative studies on the foraging behaviour of Neaphaenops tellkampfi tellkampfi and N. t. meridionalis demonstrated adaptation to different environments. The southern subspecies N. t. meridionalis, which is found in wet muddy caves where cave cricket eggs are unlikely prey, did not locate buried cricket eggs and dug fewer and less accurate holes in the lab than the nominate subspecies. N. t. tellkampfi, which reaches high densities in sandy deep cave environments where cricket eggs are the only viable prey, gained significantly greater weight than meridionalis when presented buried cricket eggs as prey. There was no difference with respect …

Troglobius Coprophagus, A New Genus And Species Of Cave Collembola From Madagascar, With Notes On Its Ecology, José G. Palacios-Vargas, Jane Wilson

International Journal of Speleology

Troglobius coprophagus n. g., n. sp. a cave Collembola from Madagascar is characterized by an elongate and serrate mucro, a non spines dens. Description and illustrations of the new genus and species are given. Some ecological data of this highly cave adapted species is also included.

Ultrastructure Des Sensilles Cylindriques, Mécanorécepteurs D'Un Crustacé Mysidacé Souterrain, Yves Crouau

International Journal of Speleology

The ultrastructural features of a new chordotonal sensillum in a cavernicolous Mysidacea is described. That sensillum and the other mechanoreceptor sensilla of the same Mysidacea are compared. 9 + 0 cilia show ultrastructural features which previously allowed us to establish a hypothesis with respect to the mode of functioning of chordotonal sensilla. That sensillum shows a pore at the tip of its external receptor.

Secondary Sympatric Occurrence Of Sibling Species Of Subterranean Shrimps In The Karst, M. Cobolli Sbordoni, M. Mattoccia, G. La Rosa, E. De Matthaeis, V. Sbordoni

International Journal of Speleology

Allozyme variation at 32 gene loci was studied in cave dwelling shrimps of the genus Troglocaris (fam. Atyidae). Populations were collected from several caves and wells belonging to different drainage systems in the Karst areas of NE Italy. Results suggest the existence of two sympatric, genetically distinct, biological species (provisionally indicated as species A and B in the T. anophthalmus complex) in the samples collected at the Duino Well, Sagrado and Comarie caves (Nei’s `D= 0.209). Samples from Gradisca and Aurisina are represented by only one (A) or the other (B) of the two species, respectively. Two remaining eastern populations …

Isopoda (Crustacea: Isopoda: Microcharon, Jaera, Proasellus) And Other Fauna In Hypogean Waters Of Southern Cyprus, Boris Sket

International Journal of Speleology

Springs and wells in SW and S part of Cyprus were briefly surveyed. Chlorinity was 0.1 - 0.8 p.p.t. Some isopods were found in collecting galleries of springs and in wells in calcarenites and in gravel deposits. These were Proasellus coxalis ssp. with some depigmented specimens, the probably stygobitic P. c. nanus ssp. n., poorly pigmented Jaera italica, and Microcharon luciae n. sp.; they were accompanied by the stygobitic amphipod Bogidiella cypria, by Turbellaria (Tricladida), by Copepoda (Cyclopoida), and rarely by some other animals (Pisidium sp., Oligochaeta). Only slightly depigmented Turbellaria Tricladida (cf. Dugesia sp.) occur in …

Two New Niphargus Species (Amphipoda) From Caves In Yugoslavia, Gordan Karaman, Boris Sket

International Journal of Speleology

Niphargus numerus sp. n. from the Čavlinska pećina near Obrovac (Dalmatia) and N. factor sp. n. from Vjetrenica (Hercegovina) are described. Both new species from Yugoslav caves belong to the N. transitivus aggregate of species.

Topographic And Volcanic Asymmetry Around The Red Sea: Constraints On Rift Models, Timothy H. Dixon, Erik R. Ivins, Brenda J. Franklin

School of Geosciences Faculty and Staff Publications

The Red Sea rift is asymmetric, with the locus of uplift and Tertiary volcanism in Saudi Arabia, 200–400 km east of the present rift axis. One model for this asymmetry involves simple shear extension on an east dipping, low-angle master fault that penetrates the lithosphere. Uplift and volcanism would mark the location where the fault enters the asthenosphere. However, observed seismicity, regional heat flow, and sedimentation are not in accord with this model's predictions. An alternate model involves interaction of upwelling asthenosphere in the early rifting stage with a nearby crustal weak zone such as a suture that controls rift …

Surface Sediments And Their Relationship To Water Quality In Hillsborough Bay, A Highly Impacted Subdivision Of Tampa Bay, Florida, J.O.R. Johansson, A.P. Squires

Reports

This paper will summarize the composition of surface sediment and sediment oxygen demand rated in Hillsborough Bay. Also, a first attempt is made to relate the nutrients released from these sediments to the phytoplankton, the dominant primary producers of the bay.

Distribution Patterns And Accumulation Rates Of Fine-Grained Sediments In Upper Tampa Bay, Florida, Gregg R. Brooks

Reports

Tampa Bay, a drowned river valley, is the largest estuary on Florida's west coast.

Surface sediments consist of a mixture of carbonate and terrigenous clastic sands and muds.

The objectives of this study are to determine accumulation rates and processes controlling the distribution patterns of fine grain sediments.

Casa Central And South America Gps Geodesy, James Kellogg, Timothy H. Dixon, R. Neilan

School of Geosciences Faculty and Staff Publications

In January 1988, scientists from over 25 organizations in 13 countries and territories cooperated in the largest Global Positioning System (GPS) campaign in the world to date (Table 1) [Neilan et al., 1988]. From January 18 to February 5, 1988, 43 GPS receivers collected about 590 station-days of data in American Samoa, Australia, Canada, Colombia, Costa Rica, Ecuador, New Zealand, Norway, Panama, Sweden, United States, West Germany, and Venezuela. The experiment was entitled CASA UNO, an acronym for Central and South America—and “uno” is Spanish for “one,” designating first-epoch measurements. The CASA UNO experiment was the first civilian …

Rakov Škocjan Karst Valley, Peter Habič, Rado Gospodarič

International Journal of Speleology

Geological, geomorphological and speleological description of the Rak Valley with several caves and natural bridges.

Trieste Karst: Geological And Stratigraphical Notes, Franco Cucchi, Nevio Pugliese, Furio Ulcigrai

International Journal of Speleology

Detailed geological and stratigraphical description of the Karst of Trieste.

Caratteristiche Mineralogiche Delle Grotte Del Carso Triestino, Graziano Cancian, Francesco Princivalle

International Journal of Speleology

Mineralogical description of terra rossa, alluvial sediments, guano deposits, oxides, carbonates and gypsum found in caves of the Trieste Karst.

I Campi Solcati Di Borgo Grotta Gigante Nel Carso Triestino, Franco Cucchi, Nadia Radovich, Ugo Sauro

International Journal of Speleology

Detailed description of the karren fields close to Borgo Grotta Gigante near Trieste, with very detailed maps, pictures and tables.

Škocjanske Jame Speleological Revue, Peter Habič, Martin Knez, Janja Kogovŝek, Andrej Kranjc, Andrej Mihevc, Tadej Slabe, Stanka Šebela, Nadja Zupan

International Journal of Speleology

Historical overview of the investigations and of the touristic display of the Skocjanske Jame cave with geological, geomorphological, sedimentological and speleogenetical outlines.

La Storia Della Speleologia Triestina In Relazione Al Problema Timavo, Fabio Forti

International Journal of Speleology

Historical overview of Speleological researches carried out to understand the Timavo problem near Trieste.

Lineamenti Geomorfologici Della Costa E Dei Fondali Del Golfo Di Trieste E Considerazioni Sulla Loro Evoluzione Tardo-Quaternaria, Ruggero Marocco

International Journal of Speleology

Description of geomorphology of the coasts and the seafloor of the Gulf of Trieste, with paleogeographical discussion on its Late Quaternary evolution.

Caratteri Generali Delle Morfologie Nelle Alpi E Prealpi Giulie E Nel Carso Triestino, Franco Vaia

International Journal of Speleology

The morphology of the Julian Alps and Prealps and of the Triestian Karst are here shortly described; the structures, which defined its origin and development, are also considered. We can notice some cliffs which follow one another from the State boundary to the Adriatic sea; they are made up by lithologic successions, which repeat themselves according to the latitude. Anyway we recognize a general outcropping of rock masses which are decreasing little by little southward as regards the altitude, the age and than the erodibility. There are some differences between the western (Carnian) and the eastern (Julian) bend of the …

The Cultural Eutrophication Of Koontz Lake, Indiana: Causes, Consequences, Correction, Willaim B. Eviston, Thomas Crisman

School of Geosciences Faculty and Staff Publications

No abstract provided.

Variation In Sulfur Dioxide Emissions Related To Earth Tides, Halemaumau Crater, Kilauea Volcano, Hawaii, Charles B. Connor, Richard E. Stoiber, Lawrence L. Malinconico Jr.

School of Geosciences Faculty and Staff Publications

Variation in SO₂ emissions from Halemaumau crater, Kilauea volcano, Hawaii is analyzed using a set of techniques known as exploratory data analysis. SO₂ flux was monitored using a correlation spectrometer. A total of 302 measurements were made on 73 days over a 90‐day period. The mean flux was 171 t/d with a standard deviation of 52 t/d. A significant increase in flux occurs during increased seismic activity beneath the caldera. SO₂ flux prior to the this change varies in a systematic way and may be related to variation in the tidal modulation envelope.

Effect Of Wet Tropospheric Path Delays On Estimation Of Geodetic Baselines In The Gulf Of California Using The Global Positioning System, David M. Tralli, Timothy H. Dixon, Scott A. Stephens

School of Geosciences Faculty and Staff Publications

Geodetic baseline measurements using the Global Positioning System (GPS) were acquired in the Gulf of California between Loreto and Cabo San Lucas in Baja California and Mazatlan on the mainland of Mexico. Tropospheric water vapor content was high during the experiment, typically yielding wet path delays in excess of 20 cm at zenith. Surface meteorological (SM) and water vapor radiometer (WVR) measurements were recorded at each site, providing independent means of calibrating the GPS signal for the wet tropospheric path delay. Residual wet delays at zenith are estimated as constants and also as first-order exponentially correlated stochastic processes. In addition, …

Evolutionary Genetics And Morphometrics Of A Cave Crayfish Population From Chiapas (Mexico), Valerio Sbordoni, Giuliana Allegrucci, Fabiola Baldari, Donatella Cesaroni

International Journal of Speleology

The recently explored Cueva de Los Camarones, in the remote village of Constitucion, Chiapas, Mexico, houses a unique highly variable population of Procambarus crayfish (Crustacea, Decapoda). Morphologically, a more or less clinal variation is revealed at several features such as the degree of rudimentation in both pigmentation and eye, and the elongation of body and appendages. Extremes are quite different, ranging from typical dark, thick, eyed individuals to light, elongated, microphtalmic phenotypes. Evolutionary relationships among individuals were investigated electrophoretically (25 structural gene loci) and morphometrically (12 characters) by means of multivariate analyses. Results from analysis of individual allozymic multilocus profiles …

Lake Apopka Trophic Structure Manipulation, Thomas Crisman, John R. Beaver

School of Geosciences Faculty and Staff Publications

No abstract provided.