This unparelleled reference synthesizes the methods used in microfacies analysis and details the potential of microfacies in evaluating depositional environments and diagenetic history, and, in particular, the application of microfacies ...
Author: Erik Flügel
Publisher: Springer Science & Business Media
This unparelleled reference synthesizes the methods used in microfacies analysis and details the potential of microfacies in evaluating depositional environments and diagenetic history, and, in particular, the application of microfacies data in the study of carbonate hydrocarbon reservoirs and the provenance of archaeological materials. Nearly 230 instructive plates (30 in color) showing thin-section photographs with detailed explanations form a central part of the content. Helpful teaching-learning aids include detailed captions for hundreds of microphotographs, boxed summaries of technical terms, many case studies, guidelines for the determination and evaluation of microfacies criteria, for enclosed CD with 14000 references, self-testing exercises for recognition and characterization skills, and more
The Jacksboro Limestone is a member of the Graham Formation of the Virgilian (Upper Pennsylvanian) and is exposed only in and around the city of Jacksboro in central Jack County, Texas.
Author: Claudio Manuel Leyva
The Jacksboro Limestone is a member of the Graham Formation of the Virgilian (Upper Pennsylvanian) and is exposed only in and around the city of Jacksboro in central Jack County, Texas. The purposes of this investigation were to study the vertical and lateral microfacies changes that occur throughout the Jacksboro Limestone in its outcrop belt and to discuss its relationship as the basal regressive cycle in the Virgilian part of the Pennsylvanian, in particular: (1) to describe and classify the primary limestone lithofacies on the basis of carbonate rock textures, (2) to interpret, if possible, the depositional environment and physical energy of the environment, based on the carbonate rock textures and allochemical constituents, and (3) to describe the diagenetic properties and carbonate petrology of the Jacksboro Limestone. The primary sources of information for this investigation were samples collected in two large active limestone quarries, the Richards Pit and P & S Stone, as well as several other exposures located along a narrow northeast-southwest trending outcrop belt in the Jacksboro, Texas area. The basic criteria used to classify the limestone types were the classification systems of Folk (1959 and 1962) for thin sections and Dunham (1962) for hand specimens. Based on binocular and petrographic examination of polished surfaces and thin sections, the carbonate beds of the Jacksboro Limestone are composed of several limestone textures. These textures are often mud supported with various proportions of fossil allochems, but generally the carbonate mud content decreases, and the proportions of fossils become more diverse from the base to the top of the sections studied. The limestone textures exhibit faunal and floral constituents including: fusulinids, foraminifers, brachiopods, gastropods, and crinoids that are commonly associated, but phylloid algae dominates the bulk of the skeletal constituents, except in a few beds. Field and laboratory analysis indicates that the Jacksboro Limestone formed on the sea floor as mound of loose accumulation of detrital skeletal grains and chemically and biologically precipitated carbonate mud in a warm, shallow, relatively low energy, marine environment. In situ skeletal constituents and encrusting organisms existed but are not significant, thus the limestone mass is interpreted as a phylloid algal, bioclastic mound. Diagenesis of the carbonate sediments is widespread. Pressure solution, diagenetic minerals, and cementation are present but extensive. Recrystallization and dissolution are the most common alteration in the sediments; however, from a classification standpoint, this property does not alter the depositional texture of the limestone carbonate.
"The Antler Peak Limestone of north-central Nevada forms the marine transition of the Antler overlap sequence.
Author: Donald Chad Johnson
Category: Antler Peak Limestone (Nev.)
"The Antler Peak Limestone of north-central Nevada forms the marine transition of the Antler overlap sequence. In the Edna Mountains, the limestone consists of reef mounds that are in depositional contact with older, deformed Paleozoic rocks. These mounds developed on topographic highs on the Pennsylvanian shelf. The same general depositional sequence of carbonate facies can be recognized in the four measured sections of the Antler Peak Limestone in the Edna Mountains near Golconda Summit. Corals, fusulinids, brachiopods and bryozoans with their associated carbonate microfacies are used to make detailed correlations between the four sections. Silty zones can also be used to correlate the units from the Edna Mountains to the type section in the Battle Mountains. Ten carbonate microfacies and four subfacies were identified and compared to the standard microfacies of Wilson (1975) and Flugel (1982). Two diagenetic facies were also identified when diagenetic alteration has destroyed the microfacies. The age of the Antler Peak Limestone in the Edna Mountains is late Desmoinesian to Virgilian, based on the conodonts Streptognathodus excelsus, Adetognathus lautus and Gondolella elegantula. Different species of the same genus of conodont recovered from the type section at Battle Mountain indicate a slightly different biofacies from the Edna Mountain sections. Furthermore, the occurrence of Streptognathodus elegantulus in the type section indicates that the type section includes rocks that are late Desmoinesian to mid Virgilian in age"--Document.
This is also indicated by the occurrence of bioturbation throughout these sections.
Palaeoenvironmental and microfacies analyses of the upper Cenomanian-lower Turonian limestone beds (mid-Cretaceous) of the Sergipe Basin, northeastern Brazil, were carried out. Four lithologic units and four microfacies types (MFTs) were defined, and a facies model was established for the Sergipe Basin. The microfaunal content was analysed for biostratigraphical purpose and palaeoenvironmental interpretation. Stable isotope analyses (13C, 18O) were carried out in order to estimate the completeness of the stratigraphical succession and to correlate the sampled sections. The depositional environment of the upper Cenomanian-lower Turonian transition was that of a ramp with a gentle dip. The deepening of the basin from northeast to southwest is represented by two environments exposed in the study area: the mid ramp and outer ramp. The microfauna consists mainly of foraminifers, calcispheres, radiolarians and rare ostracods. In addition, roveacrinids can be used as a biostratigraphical tool. The planktonic foraminiferal assemblages of the northeastern and central parts of the basin suggest shallow to middle neritic environments under well-oxygenated conditions. This is also indicated by the occurrence of bioturbation throughout these sections. The low-diverse, sparse benthic microfaunal assemblages of the southwestern sections in addition to lamination structures, indicate oxygen-depleted conditions in middle to deep neritic environments. A stratigraphical gap in the southern Japaratuba area was detected by the d13C curve. The observed fluctuations in the carbon isotopic curve can tentatively be correlated throughout the studied areas and is in agreement with the biostratigraphy.
We distinguish informal lower and upper members within the Mississippian to Pennsylvanian Wahoo Limestone which overlies the Mississippian Alapah Limestone. Our upper Alapah corresponds to the middle Alapah of previous workers.
A well from the Lisburne field near Prudhoe Bay was examined in core, thin section, and on well logs for comparison with Wahoo Limestone in the Arctic National Wildlife Refuge (ANWR). Carbonate cycles (parasequences) are well developed in both areas but the greater abundance of terrigenous sediment and associated carbonate facies indicate that the study well is located in a more landward position on the Wahoo carbonate ramp, closer to a source of terrigenous sediment. This report presents the preliminary results of microfacies analyses that have been conducted on 424 of a total 1,115 thin sections from the study well. The stratigraphic nomenclature extended from ANWR (the type locality of the Wahoo Limestone) is different that the terminology previously used for the subsurface Lisburne Group near Prudhoe Bay. We distinguish informal lower and upper members within the Mississippian to Pennsylvanian Wahoo Limestone which overlies the Mississippian Alapah Limestone. Our upper Alapah corresponds to the middle Alapah of previous workers. Our lower Wahoo Limestone member corresponds to the upper Alapah of previous workers. Our upper Wahoo Limestone member corresponds to the previous Wahoo Limestone and is the major hydrocarbon reservoir at the Lisburne field, which is characterized by well-developed carbonate cycles (parasequences).