Abstract The remote sensing of volcanic ash plumes from space can provide a warning of an aviation hazard and knowledge on eruption processes and radiative effects. In this paper new algorithms are presented to provide volcanic plume properties from measurements by the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS), the Advanced Along Track Scanning Radiometer (AATSR) and the Spinning Enhanced Visible and Infrared Imager (SEVIRI). A challenge of remote sensing is to provide near-real-time methods to identify, and so warn of, the presence of volcanic ash. To achieve this, a singular vector decomposition method has been developed for the MIPAS instrument on board the Environmental Satellite. This method was applied to observations of the ash clouds from the eruptions of Nabro and the Puyehue–Cordón Caulle in 2011 and led to a sensitive volcanic signal flag which was capable of tracking changes in the volcanic signal spectra as the plume evolved. A second challenge for remote sensing is to identify the ash plume height. This is a critical parameter for the initialization of algorithms that numerically model the evolution and transport of a volcanic plume. As MIPAS is a limb sounder, the identification of ash also provides an estimate of height provided the plume is above about 6 km. This is complemented by a new algorithm, Stereo Ash Plume Height Retrieval Algorithm, that identifies plume height using the parallax between images provided by Along Track Scanning Radiometer-type instruments. The algorithm was tested on an image taken at 14:01 GMT on 6 June 2011 of the Puyehue–Cordón Caulle eruption plume and gave a height of 11.9±1.4 km, which agreed with the value derived from the location of the plume shadow (12.7±1.8 km). This plume height was similar to the height observed by MIPAS (12 ± 1.5 km) at 02:56 GMT on 6 June. The quantitative use of satellite imagery and the full exploitation of high-resolution spectral measurements of ash depends upon knowing the optical properties of the observed ash. Laboratory measurements of ash from the 1993 eruption of Mt Aso, Japan have been used to determine the refractive indices from 1 to 20 µm. These preliminary measurements have spectral features similar to ash values that have been used to date, albeit with slightly different positions and strengths of the absorption bands. The refractive indices have been used to retrieve ash properties (plume height, optical depth and ash effective radius) from AATSR and SEVIRI instruments using two versions of Oxford-RAL Retrieval of Aerosol and Cloud (ORAC) algorithm. For AATSR a new ash cloud type was used in ORAC for the analysis of the plume from the 2011 Eyjafjallajökull eruption. For the first c . 500 km of the plume ORAC gave values for plume height of 2.5–6.5 km, optical depth 1–2.5 and effective radius 3–7 µm, which are in agreement with other observations. A weakness of the algorithm occurs when underlying cloud invalidates the assumption of a single cloud layer. This is rectified in a modified version of ORAC applied to SEVIRI measurements. In this case an extra model of a cloud underlying the ash plume was included in the range of applied models. In cases where the plume overlay cloud, this new model worked well, showing good agreement with correlative Cloud–Aerosol Lidar with Orthogonal Polarization observations.

Abstract Four case histories of textural and reservoir analyses of selected Paleozoic carbonate cycles and reef complexes of the Western Canada basin have been utilized in the formulation of a carbonate rock classification chart. This chart is presented to illustrate the relationships of grain, matrix, and cement variants of carbonate rocks, to porosity and permeability determinations, and should satisfy the requirements of an oil geologist or reservoir engineer. Large stratigraphic accumulations of oil have been discovered at or near the Paleozoic subcrop of the Mississippian “Midale” carbonate cycle in southeastern Saskatchewan. Apart from scattered, vuggy, algal encrusted strand-line deposits, most of the carbonates of the “Midale” producing zone consist of sorted, silt-sized material and skeletal or nonskeletal limestones which have a very finely comminuted, commonly dolomitized, limestone matrix with intergranular and chalky porosity. Effective reservoir porosity is controlled by the relative distribution, grain size, and sorting of this matrix. Major hydrocarbon (oil and gas) reserves have been found in the Mississippian “Elkton” carbonate cycle, both in the foothills belt and along the subcrop, in southwestern Alberta. Effective reservoir material of this cycle was found to consist mainly of the dolomitized equivalent of originally coarse, uncemented skeletal limestone, and skeletal limestone with a variable amount of generally porous, finely comminuted (granular) skeletal matrix. Primary porosity was very important in the control of dolomitization, which began with the replacement of this matrix by euhedral rhombohedrons, and finally affected the coarse skeletal material (now generally indicated by leached fossil-cast outlines). These porous dolomites grade laterally in a predictable way into tight, relatively nondolomitized, well sorted, coarse skeletal (locally oolitic) limestones with original high interfragmental porosity now completely infilled with clear crystalline calcite. This lithification by cementation took place early in the history of carbonate sedimentation of this area and before secondary dolomitization processes took effect. The transgressive, reef-fringed, limestone banks or platforms of the Upper Devonian Beaverhill Lake formation in the Swan Hills region of Alberta have been found to contain major reserves of oil and gas. Successive rims of organic lattice, stromatoporoidal and algal, atoll-like “buildups,” with granular matrix, separate generally medium to dark brown pelleted lime muds containing abundant amphiporids, and intercalated lighter colored lagoonal carbonates, from open marine shales and nodular, argillaceous, crinoid- and brachiopod-rich limestones. The most effective reservoir material along the reef fronts or terraces consists of vuggy organic lattice, algal encrusted amphiporids (minor developments), uncemented skeletal or nonskeletal limestone, and reworked stromatoporoidal, algal, and amphiporid material with intra- organic vugs, embedded in a porous, well sorted, micro to finely granular matrix. Matrix grain size and sorting studies are essential to exploration and secondary recovery problems, as the granular material grades laterally into chalky or micrograined limestones, which were laid down under lower energy conditions. Matrix granularity ratio outlines are considered to be superior to ecological maps (percentage of algal and stromatoporoidal material) in the prediction of shoal areas. The highly productive Nisku, regressive, dolomitized biostromal-evaporite complex of the Edmonton and Red Deer areas of Alberta, contains numerous stratigraphic and/or structural traps. Zonation of Nisku dolomites has been accomplished by crystal size and shape studies in combination with identification of vestiges of original organic structures and skeletal or nonskeletal grain outlines. The morphological expression of the underlying Leduc reef platforms and carbonate buildups in the Duvernay formation strongly influences facies variations of the Nisku carbonate-evaporite unit. An algal, stromatoporoidal, coralline, organic lattice chain associated with generally coarse, dolomitized, clastic carbonates with a porous, granular matrix is developed on the Rimbey-Meadowbrook trend, and forms a front to a shale- limestone facies deposited under open marine conditions to the northwest. To the east of this barrier, a complex pattern of fringing organic and clastic carbonate shoals separate locally silled, lagoonal deposits of evaporites and brown carbonate muds containing abundant secondary anhydrite-replaced amphiporids. The shoal and lagoonal carbonates throughout most of this area are overlain by anhydrite or anhydride dolomite sheets, which were precipitated in the wake of an overall regressive Nisku sea.

Abstract The Jurassic system in Saskatchewan is represented by four formations, herein described and named in ascending order, the Watrous, Gravelbourg, Shaunavon, and Vanguard formations. The Watrous formation is largely continental in nature, the overlying three formations are marine. Tentative correlations have been made with Jurassic formations in Montana and South Dakota. All formations overlap northward and westward onto the truncated surface of the Paleozoic, and are truncated northward from the International Boundarv by pre-Cretaceous erosion.