3,810,557 research outputs found
Breccia beds in the Khuff (Permian-Triassic) in Ras Al Khaimah, United Arab Emirates: collapse or transgressive origin?
No full textThe laterally extensive, so-called mid-Bih breccia beds occur in carbonate su ccess ions of the Upper Permian-Lower Triassic Khuff-equivalent Bih Formation in Ras Al Khaimah, United Arab Emirates
(UAE). These carbonates have been deposited on a stable platform setting at the passive margin of the Neo-Tethys Ocean. The breccia beds have previously been interpreted to be formed by dissolution
of sulphate beds by groundwater followed by collapse of overlying carbonate beds (Strohmenger et al., 2002; Fontana et al., 2010). Contrary to this earlier interpretation, we present several lines of field, petrographic, isotopic and fluid inclusion evidence suggesting that the "breccias" are intraformational conglomerates representing a major marine transgressive surface
The partitioning and distribution of zinc, nickel, chromium and copper in western Lake Erie sediments.
No full textPrevious research on trace metals in aquatic sediments have employed nonselective extractants which do not address the partitioning of trace metals. Partitioning data is important in environmental geochemistry because it can reveal a great deal of information about the source and distribution of the trace metals. A sequential extraction procedure was designed to examine the partitioning of anthropogenically derived Zn, Ni, Cr, and Cu in western Lake Erie sediment. The <63 micron size fraction of twenty surficial sediment samples were subjected to a three step extraction procedure that examined trace metals: (1) adsorbed on the surface of sediment grains and/or bound to carbonates, using 1.0M Na-Acetate; (2) bound to organic matter, using 0.1M Na-pyrophosphate; and (3) bound to Fe-Mn oxides, using 1.0 M Hydroxylamine hydrochloride. (Abstract shortened by UMI.) Source: Masters Abstracts International, Volume: 39-02, page: 0459. Adviser: Ihsan Al-Aasm. Thesis (M.Sc.)--University of Windsor (Canada), 1998
Carbon-sulphur systematics and geochemistry of the Duvernay Formation of central Alberta.
No full textThe Upper Devonian Duvernay Formation represents one of the most important sources of conventional oil within the Western Canada Sedimentary Basin. It is an organic-rich, basinal shale and limestone sequence within the Upper Devonian Woodbend Group. Several lithofacies from the Duvernay Formation have been identified in this study. This study concentrated on the shales and mudstones of the Duvernay Formation. The terrestrial material is probably derived from the area to the north or northwest. The major diagenetic processes that affected shales and mudstones lithofacies are cementation, dolomitization and pyritization. Minor processes include physical compaction, dissolution, anhydritization and fracturing. Framboidal pyrite, non-ferroan calcite cement and matrix dolomite are of early diagenetic origin. Bacterial sulphate reduction is the main process of bacterial reduction. (Abstract shortened by UMI.)Dept. of Earth Sciences. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis2001 .G365. Source: Masters Abstracts International, Volume: 40-06, page: 1477. Advisers: Ihsan Al-Aasm; David T. A. Symons. Thesis (M.Sc.)--University of Windsor (Canada), 2001
An isotopic and fluid inclusion study of the Rock Canyon Creek, fluorite-REE deposit, southeastern British Columbia.
No full textThe Rock Canyon Creek fluorite-REE deposit is hosted by a Cambro-Ordovician to Devonian carbonate-dominated sedimentary sequence in southeastern British Columbia. Five types of dolomite have been identified: (1) microdolomite; (2) replacement, non-ferroan dolomite; (3) saddle dolomite I, (4) coarse, ferroan dolomite, and (5) saddle dolomite II. Some Ordovician microdolomite falls in the isotopic range of typical Ordovician marine carbonates. Non-ferroan dolomite, which predates mineralization, is more depleted in 18O and 13C than microdolomite. The precipitation of saddle dolomite I, which predates mineralization, is related to veins and vugs. Geochemical and petrographic evidence suggest that saddle dolomite I and non-ferroan dolomite were precipitated from a hot, slightly saline fluid. Pervasive coarse ferroan dolomite occurs in most host rocks to the fluorite-REE mineralization. Saddle dolomite II occurs in open space associated with fluorite and quartz, has similar isotopic compositions to ferroan dolomite and is suggested to have precipitated from the same fluid as that which precipitated ferroan dolomite. (Abstract shortened by UMI.)Dept. of Earth Sciences. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis2000 .Z56. Source: Masters Abstracts International, Volume: 39-02, page: 0464. Advisers: I. S. Al-Aasm; I. M. Samson. Thesis (M.Sc.)--University of Windsor (Canada), 2000
Clay mineralogy, hydrochemistry and sedimentological history of the quaternary sediments of the St. Clair delta area (Michigan, Ontario).
No full textThe St. Clair River delta, the largest in the Great Lakes area, is located astride the border between Michigan, United States of America (U.S.A.), and Ontario Canada. It resembles a classic river-dominated delta system, with a typical "birds foot" morphology The St. Clair River delta consists of six islands from west to east: Seaway, Bassett, Squirrel, Walpole, the artificial Pottowatamie, and St. Anne. This study is performed on three continuous vertical sediments cores The cores were taken along a north-south transect of Walpole island. The St. Clair River delta is composed of a premodern and modern sediments. Sediments of the premodern delta were deposited from 3 500 to 5 000 B.P. at an elevated lake level. The sedimentation of modern sediments started about 3 500 B.P. and continues to this day. Beneath the delta, lacustrine and sediments are found. The clay minerals of the day fraction are determined to identify the glacial detrital sources, the sedimentary processes and the past environmental changes. Two sites for shallow groundwater sampling were selected in the centre of Walpole Island to evaluate the environmental impact of the landfill and surficial disposal. (Abstract shortened by UMI.)Dept. of Earth Sciences. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1997 .M63. Source: Masters Abstracts International, Volume: 39-02, page: 0467. Advisers: I. S. Al-Aasm; W. H. Blackburn. Thesis (M.Sc.)--University of Windsor (Canada), 1998
Petrology, geochemistry and diagenesis of the Middle Devonian Slave Point Formation, Hamburg Field, northwestern Alberta.
No full textThe Middle Devonian carbonates of the Slave Point Formation, Hamburg Field, northwestern Alberta, are composed mainly of stromatoporoid floatstones and rudstones which were deposited in open and restricted marine platform environments. This study is aimed at evaluating the diagenetic history of the Slave Point carbonates, with particular emphasis on dolomitization and porosity evolution. Carbonates of the Slave Point Formation have undergone a complex diagenetic history, represented mainly by cementation and dolomitization. All lithofacies are fractured and variably dolomitized. Dolomitization ranges from isolated fabric-selective dolomite rhombs, through to pervasive dolomitization. Diagenesis occurred during shallow to deep burial, with a proposed interlude of hydrothermal alteration. Four different types of dolomite have been identified: (1) matrix dolomite, (2) pseudomorphic dolomite, (3) pervasive dolomite, and, (4) saddle dolomite. Most primary porosity has been reduced by calcite cementation and compaction although minor amounts are retained. Secondary porosity makes up the reservoir porosity and includes intercrystalline, vuggy/moldic and fracture porosity; however, it is occluded to a certain extent by saddle dolomite and late stage calcite cements. (Abstract shortened by UMI.)Dept. of Earth Sciences. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1998 .C58. Source: Masters Abstracts International, Volume: 39-02, page: 0460. Adviser: Ihsen Al-Aasm. Thesis (M.Sc.)--University of Windsor (Canada), 1998
Sedimentology, dolomitization and diagenetic fluid evolution of the Middle Devonian Sulphur Point Formation, northwestern Alberta.
No full textThe Middle Devonian carbonates of the Sulphur Point Formation, Rainbow South Field, northwestern Alberta, are secondary gas-producing fractured and brecciated limestones and dolostones. These rocks have undergone complex diagenetic changes, represented mainly by multiple generations of calcite cementation and dolomitization. Calcite cements include isopachous (marine), drusy (shallow burial), equant (intermediate burial) and blocky (deep burial) varieties. Four types of dolomite have been identified: dolomicrite, matrix dolomite, saddle dolomite, and fracture-lining dolomite. Dolomicrite (2--20 mum) replaced both micrite and calcite cement in the mud-supported facies prior to early compaction. Matrix dolomite formed during intermediate burial. The precipitation of saddle dolomite (0.5--2.0 mm) is genetically related to fractures and breccia zones where it partially to completely occludes the fractures, breccias and vugs that were developed through the dissolution of the earlier matrix dolomites. Fracture-lining dolomite (0.2--1.0 mm) was the last dolomite phase to precipitate, and is intimately associated with blocky calcite, quartz, sulphide mineralization, and pyrobitumen. (Abstract shortened by UMI.)Dept. of Earth Sciences. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1999 .L66. Source: Masters Abstracts International, Volume: 39-02, page: 0461. Adviser: Ihsan S. Al-Aasm. Thesis (M.Sc.)--University of Windsor (Canada), 1999
Sedimentology and dolomitization in the upper Mississippian Turner Valley carbonates, Quirk Creek, Alberta, Canada.
No full textThe Mississippian Turner Valley Formation at the Quirk Creek field is composed of a shallowing-upward sequence of shallow platform to restricted lagoon and sabkha carbonates with a thickness of 115 m. Major diagenetic events include: cementation, compaction, silicification, anhydritization, and dolomitization. The most important of all diagenetic events involves a continuous spectrum of early to late dolomitization. Four types or generations of dolomite are identified: microdolomite, patchy dolomite, pervasive matrix dolomite and coarse dolomite. Microdolomite (4-10 m) is dense, and locally occurs only in sabkha lithofacies. Patchy dolomite (20 to 200 m) floats between skeletal grains, and is distributed along dissolution seams and early stylolites (\delta\sp{18}O, 0.79 to 3.52 per mil PDB). Pervasive matrix dolomite or masssive dolomite (20 to 300 m) is the most abundant type of dolomite with predominantly reservoir porosity. Megadolomite (0.5 to 2 mm) consists of coarse, euhedral rhombs and moldic-dolomite. It replaces massive dolomite and crosscuts late stylolites. Megadolomite has higher Fe, Mn, and radiogenic Sr (0.70836 to 0.70875) and lowest \delta\sp{18}O 2.12 to 6.47 per mil PDB), suggesting formation in a later and deeper burial environment. The reservoir porosity of the Turner Valley Formation is mainly controlled by the degree of dolomitization. The most abundant porosity is presented in carbonates with a dolomite component of 70% to 95%. The potential reserves could be found in these carbonates. (Abstract shortened by UMI.)Dept. of Geology and Geological Engineering. Paper copy at Leddy Library: Theses & Major Papers - Basement, West Bldg. / Call Number: Thesis1993 .L844. Source: Masters Abstracts International, Volume: 32-02, page: 0568. Adviser: I. S. Al-Aasm. Thesis (M.Sc.)--University of Windsor (Canada), 1993
Fracture mineralization and fluid flow evolution: an example from the Permian-Triassic carbonate successions of United Arab Emirates
No full textFractures are often the primary conduits for pore fluids, and thus have an important impact on the diagenetic and reservoir quality evolution of the host rocks. Therefore, fluid flow can be used to
develop conceptual models for the spatial and temporal distribution and connectivity of reservoir porosity and permeability on a regional and basinal scale. In the context of the hydrocarbon-rich Middle East, the Permian-Triassic Khuff Formation hosts huge gas accumulations in the subsurface of the Arabian Plate. Reservoir properties of this formation are strongly influenced by depositional facies and diagenetic evolution (Ehrenberg et al., 2007; Fontana et al., 2010; Moradpour et al., 2008). In the Emirate of Ras Al Khaimah (RAK), in the northeast of the United Arab Emirates (UAE), there are excellent outcrops of the Permian-Triassic rock sequence, which is partly correlatable with the Khuff Formation (Strohmenger et al., 2002; Maurer et al., 2008, 2009). In this study, which involves fieldwork,
petrographic, fluid inclusion and isotope (0, C and Sr) investigations, outcrops of Permian-Triassic carbonate rocks have been studied to relate fracture mineralization to tectonic history of the area
A dozen years of American Academy of Sleep Medicine (AASM) International Mini-Fellowship: program evaluation and future directions.
No full textUNLABELLED: Sleep medicine remains an underrepresented medical specialty worldwide, with significant geographic disparities with regard to training, number of available sleep specialists, sleep laboratory or clinic infrastructures, and evidence-based clinical practices. The American Academy of Sleep Medicine (AASM) is committed to facilitating the education of sleep medicine professionals to ensure high-quality, evidence-based clinical care and improve access to sleep centers around the world, particularly in developing countries. In 2002, the AASM launched an annual 4-week training program called Mini-Fellowship for International Scholars, designed to support the establishment of sleep medicine in developing countries. The participating fellows were generally chosen from areas that lacked a clinical infrastructure in this specialty and provided with training in AASM Accredited sleep centers. This manuscript presents an overview of the program, summarizes the outcomes, successes, and lessons learned during the first 12 years, and describes a set of programmatic changes for the near-future, as assembled and proposed by the AASM Education Committee and recently approved by the AASM Board of Directors. CITATION: Ioachimescu OC; Wickwire EM; Harrington J; Kristo D; Arnedt JT; Ramar K; Won C; Billings ME; DelRosso L; Williams S; Paruthi S; Morgenthaler TI. A dozen years of American Academy of Sleep Medicine (AASM) international mini-fellowship: program evaluation and future directions
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