Search

We review currently available Canadian and international lithostratigraphic and lithodemic schemes and find most of them inadequate for classifying intrusive and strongly metamorphosed rocks of Canada and beyond. A new system is proposed, one that unifies, complements, and extends components of the revised North American Stratigraphic Code, the British Geological Survey Rock Unit Classification System of 2021, and the International Stratigraphic Guide of 1999. This new Cooperative Lithodemic and Stratigraphic System (CLASS) is intended to serve as a practical guide to geoscientists who need to classify and report on lithodemic units in North America and has broad applicability to other jurisdictions. It is built with database management practices in mind and employs the concept of inheritance of root characteristics between seven formal rock unit ranks, which will allow incorporation of the scheme into compact object-oriented and relational databases designed for purpose. Broad application of CLASS, especially to historically problematic lithodemic units, should help to foster jurisdictional interoperability, data sharing, global compilations, and thematic studies. At the heart of this proposed system is a subdivision and accompanying nomenclature that allows classification of rocks into seven formal ranks. Following the well-established lithostratigraphic supergroup, group, subgroup, formation, member, submember, and bed approach, CLASS proposes three classes of lithodemic subdivisions for formally naming lithodemic rock units. [ABSTRACT FROM AUTHOR]

An integrated study of several methods to characterize a carbonate reservoir provides a comprehensive result on carbonate facies and diagenesis. Therefore, a study on the Tertiary carbonate reservoir at the East Arm of Sulawesi area, Banggai - Sula Basin, is intended to determine the Salodik Group carbonate reservoir facies and diagenesis. Moreover, the purpose of this study is to determine the intensity and implication of syn-depositional or post-depositional processes, and to provide the reservoir final properties values, such as porosity and permeability to classify the reservoir quality. The methods of the study are based on carbonate fieldwork mapping to obtain samples on distributed traverses. Further analyses are the laboratory works to determine facies and diagenesis features on a more detailed scale. This study shows several facies, dominantly classified into reefal packstone, planktonic foraminifera packstone-wackestone, large foram packstone-mudstone, skeletal packstone-wackestone, planktonic-large foraminifera packstone-wackestone, and large foraminifera-red algae packstone. The dominant diagenesis processes are cementation and dissolution. Moreover, meteoric vadose and meteoric phreatic are predominantly the main diagenesis environment of Salodik Group formations. Furthermore, the dominant diagenesis stage is Eogenetic. The post-depositional process or the diagenetic processes, provides a more significant impact on carbonate reservoir properties than the syn-depositional process as shown on lithofacies texture. However, in general, from the younger to the oldest formation of Salodik Group, this shows a decreasing trend of reservoir properties due to the dominant cementation process in the oldest formation. Overall, the reservoir quality referring to porosity value is classified as negligible to excellent. While, based on permeability data, it is classified as the tight to good reservoir. [ABSTRACT FROM AUTHOR]

Field data from recent geological mapping over a major part of the north-central Scandinavian Caledonides combined with published information give a detailed view of early Cambrian basin successions, comprising the Gärdsjön formation (Gf; Jämtland supergroup) in the Lower Allochthon and autochthonous equivalents (Dividal Group). The Gf comprises ten units of sandstone and siltstone or mudstone (Gf I—X, > 300 m thick). Green siltstones with red layers (Gf VI, c. 521 to 519 Ma) and green–grey siltstones at the top (Gf X, c. 516.5 to 513.5 Ma) are regional key horizons. Gf V, VI, VII, IX, and X deposition may be related to eustatic events. Restoration of Caledonian shortening reveals a major "Hornavan-Vattudal basin" (HVB; > 330 km NW–SE, > 400 km NE-SW) between the Grong–Olden culmination in the S and the Akkajaure–Tysfjord culmination in the N. Published zircon ages imply the latter separated the HVB from those shed from the Timan orogen in the N. The eastern basin margin straddles the present Caledonian erosional margin. Basement highs identified here within the Nasafjället, Bångonåive, and Børgefjellet "basement" windows define the western margin. They separate the HVB from the outer shelf towards the Iapetus Ocean in the W. The onset of sedimentation is time-related with E–W extension at c. 544–534 Ma. NNE–SSW-directed extension occurs after c. 518 Ma, perhaps related with Timan late-orogenic extension. The HVB is distinctly younger (c. 535–513.5 Ma) than Rodinia break-up and Iapetus ocean formation (> 550 Ma), comparable with post-rift basins in inner parts of modern passive margins. [ABSTRACT FROM AUTHOR]

The Amb Formation of the Permian age is exposed in the Salt Range in the upper Indus basin of Pakistan. This rock unit is mainly composed of sandstone and shale in which three facies (named AF1, AF2, AF3) and five microfacies were distinguished based on field and petrographic study, respectively. Porosity and permeability have changed and exhibit various diagenetic processes. Sequence stratigraphy identifies the zones of all upward concaving cycles and HST. The petrophysical study indicates good reservoir characteristics for the Amb Formation and this can act as reservoir rock in the petroleum system. Fossil assemblages, including Fusulina spp., identified during petrographic analysis indicate an Early Permian age of the Amb Formation in the study area. The multidisciplinary study carried out in the study area allowed us to reconstruct the depositional model for the Amb Formation which occurred in the middle to inner shelf and in a shallow marine environment. Interpretation of well logs of the Dhermund well show good reservoir properties of the Amb Formation including total porosity (13%), effective porosity (9.04%), volume of shale (14.54%), water saturation (34%), hydrocarbon saturation (65%), permeability (121.92 mD), total thickness of the formation (107 m) and net reservoir thickness (13.12m). This research approach of combined field and laboratory stratigraphy and biostratigraphy would be applied in other areas of exposure of the Amb Formation to unravel the age and depositional environment of this formation. [ABSTRACT FROM AUTHOR]

Copyright of Iraqi National Journal of Earth Sciences is the property of Republic of Iraq Ministry of Higher Education & Scientific Research (MOHESR) and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In the second half of the nineteenth century, geologists created the International Geological Congress (IGC) to achieve the methodological and terminological uniformity that they thought their science lacked. Their desire to standardize their practice and their use of the conference to do so was neither new nor unique. Although late nineteenth-century international conferences have been recognized as important arenas of standardization, relatively little is known of the ways in which conferences organized standardization negotiations. This article aims to fill this gap by exploring how the IGC practically and socially organized standardization work. It appears that the session hall was not the sole and not even the main stage of geological standard-setting. The standardization process was also enacted through comparative study and informal exchanges that regular visits to purpose-built comparative geological exhibitions made possible. Relying on a sophisticated apparatus of commissions and subcommittees, the IGC also socially organized standards negotiation beyond the space and time of the triennial sessions. By tracing the material, spatial and social practices engineered through the IGC to serve geological standardization, this article unboxes the conference process and in so doing enriches our understanding of the period's wave of standardization. [ABSTRACT FROM AUTHOR]

This paper examines the emergence of a new approach to stratigraphic complexity, first in geology and then, following its creative appropriation, in paleobiology. The approach was associated with a set of models that together transformed stratigraphic geology in the decades following 1970. These included the influential models of depositional sequences developed by Peter Vail and others at Exxon. Transposed into paleobiology, they gave researchers new resources for studying the incompleteness of the fossil record and for removing biases imposed by the processes of sedimentary accumulation. In addition, they helped reconfigure the cultural landscape of paleobiology, consolidating a growing emphasis on fieldwork and eroding the barrier that had been erected in the 1970s between "paleontology" and "paleobiology." This paper traces these developments, paying special attention to the simulation models of stratigraphic paleobiologist Steven Holland. It also considers how the integration of sequence and event stratigraphy and paleobiology has begun to influence long-running discussions of incompleteness and bias in the fossil record. [ABSTRACT FROM AUTHOR]

The graptolites of the Tøyen Shale Formation of Kinnekulle in Västergötland, south-central Sweden, are described for the first time and their biostratigraphic distribution is documented from drill core and outcrop material. The faunas indicate an age of mid to late Floian (Billingenian), thus showing a reduced biostratigraphic range of the Tøyen Shale as compared to other areas where this rock unit occurs. A considerable stratigraphic gap is apparent at its base, from the late Tremadocian to mid-Floian, as the limestones of the Ceratopyge acicularis trilobite Zone (late Tremadocian Bjørkåsholmen Formation) are followed by shales with a fauna of the Baltograptus jacksoni graptolite Biozone. Unverified records suggest that mid–late Ottenbyan (Hunnebergian) strata (Megistaspis planilimbata trilobite Zone s.l.) locally may be present in the uppermost Bjørkåsholmen Formation as identified herein. There is no indication that the Tøyen Shale reaches into the Dapingian, as Dapingian graptolites have not been recognized. The overlying limestones of the "Lanna Limestone" belong to the Megistaspis polyphemus trilobite Zone and the Baltoniodus triangularis conodont Zone, suggesting a gradual contact of the lithological units. [ABSTRACT FROM AUTHOR]

The Anthropocene has been observed as an opportunity to generate new legal imaginaries capable of revising incumbent assumptions of legal and political thought. What opportunities do such ambitions afford for communication between geological and legal thought? Responding to Birrell & Matthews attempt to 're-story a law for, rather than of, the Anthropocene,' I wish to describe some ways in which the Anthropocene Working Group, who are pursuing formalisation of the Anthropocene as an official geological unit, are involved in a similar exercise of re-storying geology. The Anthropocene theme is brought to bear as a geological reality through material practices of measurement and correlation, as well as through the invocation of previous judgements of the evaluative committees associated with the formalisation of new geological unit. This effort amounts to a redefinition of the practices of geological observation, i.e. what counts as geologically relevant and why. In keeping with the theme of an 'ethics of encounter', as encouraged by Birrell and Matthews, this article suggests that the AWG's effort provides a model with which the elaboration of 'laws for the Anthropocene' might correspond. [ABSTRACT FROM AUTHOR]

Municipal administrations in Italy must be provided with thematic maps and documentation which describe the geological, geomorphological, lithological, hydrogeological and hydraulic characters useful to manage spatial planning issues. Among these documents, a "Lithotechnical" (or "Lithological-Technical") map is drawn up, generally at the scale of 1:10,000, by organizing the geological formations into lithotechnical units according to their lithological and physicalmechanical properties. Often, this map also integrates the results of previous field and borehole investigations. However, this map is characterized by a certain degree of subjectivity because it is supported by few specific quantitative data. We present a new method for the regional scale engineering geological classification of sub-surface rock and soil masses obtained by integrating the geological map at the scale of 1:10,000 as a reference document, with a large set of data obtained through the collection and processing of new lithological and physical-mechanical observations and measurements of the outcropping geological formations. The adopted procedure involves both the extensive in situ use of the Schmidt's hammer and the execution of laboratory tests, such as the Slake Durability Test (Franklin & Chandra, 1972) and the determination of the rock unit weight. These tools and tests allow us to acquire a large set of quantitative in situ and laboratory data with known repeatability to obtain a regional scale GIS database providing the classification of the lithological and physical-mechanical characteristics of a wide range of geological formations. As a first step, each outcrop is classified according to a new engineering geological nomenclature system described by the code XXv[y]_[Z] whose values are obtained by integrating: i) a lithological parameter XXv evaluated from both typical characters of the geological formations under analysis and outcrop observations; ii) an engineering geological parameter [y] obtained by the results of the Slake Durability Test; iii) an engineering geological parameter [Z] (Rockmass Quality Index - RQI) evaluated at the outcrop scale on the basis of a large set of sclerometric measurements. The results of outcrop classification are stored into a point topology GIS dataset and are then processed and spatialized in order to assign the XXv[y]_[Z] code to the geological formations, thus obtaining the new engineering geological map. Within the framework of research agreements among Regione Toscana administration, the Consorzio LaMMA, the CNRIGG and the Department of Earth, Environmental and Physical Sciences of the University of Siena, the latter being the leader for their implementation, more than 300 geological formations were analysed and classified, and the new engineering geological GIS map was realized in Tuscany for the provinces of Arezzo, Florence, Lucca, Massa-Carrara, Pistoia, Prato and Siena (ca. 15,000 km2). [ABSTRACT FROM AUTHOR]