Implications of Current House of Representatives Action to Amend the Foreign Tax Credit as Applied to Foreign Source Petroleum Income

The tax treatment of foreign-source income of U.S. oil companies is under a multi-faceted attack which arises largely from a number of serious misconceptions

Panel Discussion: American Tax Credits and Foreign Taxes and Royalties

This panel discussion primarily focuses on U.S. tax policy with regards to international oil companies

Cation distribution and valence in synthetic Al-Mn-O and Fe-Mn-O spinels under varying fO2 conditions

The spinel-group minerals, found in a range of igneous rocks, are resistant toweathering and can incorporate several multivalent elements, meaning they have the potential to provide insight into the redox conditions of parental magmas. Naturally occurring spinel can contain varying quantities of Mn, an element which occurs terrestrially and extra-terrestrially as Mn2+, Mn3+, Mn4+ and Mn5+. However, a lack of information on the effects of oxygen fugacity (fO2 ) on: (1) Mn valence state and cation distribution; and (2) on spinel-melt partitioning means that the potential for a Mn-in-spinel oxy-barometer remains largely untested. Here, we use electron probe microanalysis, micro-focus X-ray Absorption Near Edge Structure (XANES) spectroscopy and single-crystal X-ray diffraction (SC-XRD) to investigate cation distribution and valence state in spinels in the Al-Mn-O and Fe-Mn-O systems synthesized at ambient pressure under varying fO2 conditions. In contrast to previous studies, we find that the spectral resolution of the Mn K-edge XANES spectra is insufficient to provide quantitative data onMn valence state and site occupancy, although it does verify that Mn is incorporated as both Mn2+ and Mn3+, distributed over tetrahedral and octahedral sites. Combination of data from XANES and SC-XRD refinements can, however, be used to model Mn, Al and Fe valence and site occupancy. It would be expected thatMn-Fe spinels have the potential to record fO2 conditions in parental melts due to changes to the octahedral site under conditions that were more reducing. However, decoupling the effects of temperature and oxygen fugacity on the TFe3+-TMn2+ exchange in the Mn-Fe spinels remains challenging. In contrast, little variation is noted in Mn-Al spinels as a function of fO2 , implying that crystal chemistry and cation site geometry may significantly influence cation distribution, and by inference, crystal-melt partitioning, in spinel-group minerals

An integrated study of geochemistry and mineralogy of the Upper Tukau Formation, Borneo Island (East Malaysia): Sediment provenance, depositional setting and tectonic implications

An integrated study using bulk chemical composition, mineralogy and mineral chemistry of sedimentary rocks from the Tukau Formation of Borneo Island (Sarawak, Malaysia) is presented in order to understand the depositional and tectonic settings during the Neogene. Sedimentary rocks are chemically classified as shale, wacke, arkose, litharenite and quartz arenite and consist of quartz, illite, feldspar, rutile and anatase, zircon, tourmaline, chromite and monazite. All of them are highly matured and were derived from a moderate to intensively weathered source. Bulk and mineral chemistries suggest that these rocks were recycled from sedimentary to metasedimentary source regions with some input from granitoids and mafic-ultramafic rocks. The chondrite normalized REE signature indicates the presence of felsic rocks in the source region. Zircon geochronology shows that the samples were of Cretaceous and Triassic age. Comparable ages of zircon from the Tukau Formation sedimentary rocks, granitoids of the Schwaner Mountains (southern Borneo) and Tin Belt of the Malaysia Peninsular suggest that the principal provenance for the Rajang Group were further uplifted and eroded during the Neogene. Additionally, presence of chromian spinels and their chemistry indicate a minor influence of mafic and ultramafic rocks present in the Rajang Group. From a tectonic standpoint, the Tukau Formation sedimentary rocks were deposited in a passive margin with passive collisional and rift settings. Our key geochemical observation on tectonic setting is comparable to the regional geological setting of northwestern Borneo as described in the literature

Lithostratigraphy, palynostratigraphy, and sedimentology of the Northern Skeena Mountains and their implications to the tectonic history of the Canadian Cordillera

The Skeena Mountains of north-central British Columbia contain exposures of more than 4500 m of Jura-Cretaceous strata deposited in the Bowser Basin. These strata were deposited as a result of tectonism that formed the Canadian Cordillera, and serve as a record of the tectonic history of the Cordillera. The strata of the north-central Bowser Basin have been the subject of an integrated lithostratigraphic, palynostratigraphic and sedimentologic study in order to better understand the depositional history of the basin and the tectonic history of the Cordillera. The study area is in the northern Skeena Mountains, approximately coincident with boundaries of the Groundhog coalfield. Four hthostratigraphic units are exposed in the study area. The upper three units, consisting of over 2000 m of strata, are well exposed, and are formally named herein, from oldest to youngest, the Currier, McEvoy and Devils Claw Formations. Underlying the Currier Formation is the informally named Jackson unit, which comprises the oldest exposed strata in the study area. Together, the Jackson unit and Currier Formation comprise the Bowser Lake Group. The McEvoy and Devils Claw Formations unconformably overlie the Bowser Lake Group and correlate with the Skeena Group. Palynostratigraphy has been used successfully to correlate and date the sediments. Marine macrofossils are rare above the Jackson unit, necessitating use of palynomorphs to date the strata. Recovery of palynomorphs from anthracite rank coal measures has proven possible by extended treatment in Shulze's solution. The Currier Formation is suggested to be Late Jurassic (Oxfordian to Kimmeridgian or Tithonian) in age. The overlying McEvoy and Devils Claw Formations are entirely Cretaceous in age. The McEvoy Formation extends from the late Barremian or Aptian to the middle or late Albian, and the Devils Claw Formation spans the middle or late Albian to the Cenomanian. Two sedimentologically distinct deltaic sequences have been interpreted from the lithofacies associations. Both delta sequences probably accumulated in relatively shallow water, suggesting shallow shelf deposition. The older deltaic sequence occurs in the Currier Formation, and is analogous to facies of the modern Mississippi delta. The younger deltaic sequence encompasses strata of the McEvoy and Devils Claw Formation, and is more analogous to the coarse grained delta of the Copper River. The two delta sequences are separated by a hiatus of 20 to 35 million years. Sediment provenance, interpreted from paleocurrent data and clast lithologies, appears to have remained the same during deposition of both deltaic sequences. Paleocurrent indicators point to a source to the east-northeast, and the dominance of chert suggests a dominantly sedimentary source terrane, likely the Cache Creek Group. North American provenance is consistent with paleocurrent indicators and clast lithologies. The tectonic history of the Cordillera is related to the depositional history of the Bowser Basin. Subsidence, as indicated by sediment accumulation, occurred during the Middle and Late Jurassic and probably decreased near the end of the Jurassic, leading to a period of tectonic quiescence in the Cordillera. Subsidence resumed near the end of the early Cretaceous, leading to another period of deltaic sedimentation. This second deltaic sequence, represented by strata of the McEvoy and Devils Claw Formations, is coarser than the Late Jurassic delta, which suggests a more rugged and proximal source area.Science, Faculty ofEarth, Ocean and Atmospheric Sciences, Department ofGraduat

Competition in the Field Market for Natural Gas

Acknowledgements-- Introduction-- Chapter I. Production, Consumption, and Prices of Natural Gas-1920-1955-- Chapter II. Structure of the Field Market for Natural Gas-- Chapter III. Other Factors Pertaining to the Comptetiveness of the Market-- Conclusion-- Note

Lithofacies, provenance, and diagenesis of jura-cretaceous strata of the Northern Bowser Basin, British Columbia

Lithofacies, provenance, and diagenetic studies of more than 3 km of Late Jurassic to mid-Cretaceous silicilastic sediments exposed in the northern Bowser Basin (northern British Columbia) record the tectonic development of the Canadian Cordillera. Strata are divided into the undivided Bowser Lake Group and overlying Currier, McEvoy, and Devils Claw formations Lithofacies include marine mudstone, coarsening upward mudstone, fining upward sandstone, coarsening upward sandstone, chert pebble conglomerate, and coal. Common lithofacies associations are interpreted as a progression (from older to younger) of shallow marine, lower delta plain, upper delta plain, and alluvial braid-plain depositional environments. A subsidence model based on sediment compaction and isostatic load accounts for the necessary accommodation space. The composition of the sandstone suggests an obducted island arc and oceanic crust asprovenance. Three petrofacies have been identified by modal analysis of framework grains. Petrofacies 1(P1), which occurs in undivided Bowser Lake Group and Currier Formation strata, (QtFL = 34-14-52;QmFLt = 9-14-77) is volcanic lithic rich with subequal to minor chert, minor monocrystalline quartz(generally <10%), and 10-25 % feldspar. Petrofacies 2 (P2) occurs in lower McEvoy Formation, and has higher concentrations of chert reflecting a recycled component in the sandstones, but also retains significant portions of volcanics (QtFL = 62-5-33; QmFLt = 5-5-89). Petrofacies 3 (P3) occurs in the upper McEvoy and Devils Claw formations, and is chert rich like P2, with less volcanic lithics and a small but significant portion of metamorphic lithic fragments (Qt =64 %, F=5%, L=31 %; Qm=7%,F=5%, Lt= 88 %). Paleocurrent directions indicate transport from northeast to southwest. Microprobe analysis of detrital chromian spinel accessory grains demonstrates alpine type peridotite occurs in the provenance. No spinels typical of mid-ocean ridge or Alaskan type complexes were found. The petrofacies and chromian spinel chemistry are consistent with a provenance from island arc and marginal basin lithosphere obducted onto the western margin of North America. Diagenetic history of the sediments provides insight into depositional and post depositional processes in the basin. Seven stages of cement paragenesis are recognized in the sandstones: 1) chlorite; 2) illite; 3) kaolinite; 4) dead oil; 5) quartz; 6) chlorite dissolution; and 7) calcite. Estimated precipitation temperatures begin below 80°C for chlorite, and increase to approximately 100°C to200°C for quartz, and to above roughly 200°C for calcite. Fluid inclusions in quartz cements support such temperature estimates. The succession of cements is interpreted to record replacement of original connate seawater by acid pore waters derived from organic matter maturation that were forced out by compaction of the interbedded muds. Carbon isotopes in carbonate concretions from the mudstones are consistent with formation during a late stage of methanogenesis. Oxygen isotopes from the same concretions suggest pore fluids in the muds at the time of formation were meteoric to brackish waters typical of cool temperate climates. Organic maturation was modelled by using vitrinite reflectance values from interbedded coals and mudstones, and assuming progressive heating as inferred from the sandstone cement paragenesis. Results of the model indicate that a high paleogeothermal gradient, similar to some back arc basins, best explains the diagenetic history of the northern Bowser Basin. Constraints from the lithofacies, provenance, and pore water evolution studies suggest the Bowser Basin began as a deep marine basin which was filled by sediment derived from island arc and marginal basin crust obducted earlier onto the western margin of North America.Science, Faculty ofEarth, Ocean and Atmospheric Sciences, Department ofGraduat