The Kope Formation is a rock unit that extends over southwest Ohio and adjacent areas of Kentucky and Indiana, USA. It is characterized by meter-scale cycles of mudstones and limestones where thick ...mudstone is sandwiched between thin limestone layers. Kope Formation mudstones are less durable than the mudstones in the area. They cause abundant slope failures in areas of their outcrops. This study evaluates chemical, mineralogical and textural properties of Kope mudstones to determine why it is less durable. The Two-cycle slake durability index (ID2) was measured on thirty mudstones belonging to three consecutive cycles of the Kope Formation. Chemical composition and mineralogy of Kope mudstones do not show significant relationship with the ID2. Instead, a relationship to fabric was found. Kope mudstones with two main fabric types were observed in the field; laminated mudstones and non-laminated mudstones. Detailed micro-fabric analysis on Kope mudstones was done using the scanning electron microscope. Laminated mudstones with turbostratic fabric showed higher ID2 and lower moisture content than the non-laminated mudstones with matrix fabric. The difference in the ID2 of laminated mudstones and non-laminated mudstones is statistically significant. Both mudstone types exist in many cycles of the Kope Formation. Thus, core samples should be selected from both types for preliminary tests in geotechnical practice, to obtain more accurate estimations of the geotechnical properties of the Kope mudstones. The results and data interpretations of this study can be correlated with the mudstones and shale in different areas of the world. Specifically, a great attention should be paid to the macro and micro textural properties of any rock type regardless of their classification.
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•The Kope Formation mudstones have two main types of fabric.•Laminated mudstones have turbostratic fabric and high slake durability index.•Non-laminated mudstones have matrix fabric and low slake durability index.•Laminated mudstones are more durable than non-laminated mudstones.
Kope cheese has been characterized based on gross chemical composition, free fatty acids (FFAs), organic acids (OAs), volatile compounds (VCs), and sensory attributes (SAs) during 187 days of the ...ripening period. C16:0, C18:1cisΔ9, and C14:0 were the most abundant FFAs. Lactic and acetic acids were the most prevalent OAs affecting sensory properties. principal component analysis (PCA) indicated that butanoic acid, butyl hexanoate, and 2,3‐butanediol were as key VCs. Protein contents, pH (based on FFA and OA), salt in the moisture (S/M), and water activity (aw) (based on VC and SA) were highly correlated with PC2, resulted in two distinct groups. Based on lipolysis and glycolysis studies, early‐ripened cheese samples showed lipolysis and lactate metabolism more intensely compared to medium and old‐ripened ones. Based on the data of VC and SA, the samples may be classified into three groups: (1) early‐ripened cheeses with a salty taste, waxy to cheesy odor, and rubbery texture, (2) medium‐ripened cheese with a sweet taste and cheesy odor, and (3) old‐ripened cheese with a bitter taste, cheesy to pungent odor, a firm and fragile texture. Textural attributes were highly correlated with proteolysis indices and pH. The results of sensory desirability indicated a significant correlation with pungency, bitterness, and OAs. The cheese samples ripened on the day 127 were selected as the most desirable product. Ripening time had a significant effect on the chemical composition, especially on S/M, pH, and aw parameters, which determine the pattern as well as the intensity of biochemical pathways and the final sensory attributes.
Practical Application
The current study intends to characterize and develop a standardized procedure for producing a traditional cheese called “Kope cheese” by determining the appropriate duration time for the ripening process, determining the main chemical/biochemical compounds that are highly correlated with its unique flavor and texture and distinguishing the key processing factors (such as curd salting, pH values during brining) that have to be altered or controlled carefully during the manufacturing process. The data would help cheese manufacturers determine the optimum time of ripening in order to achieve the best flavor and texture attributes in the final product.
The Upper Ordovician Cincinnatian Series is a critical upper Katian reference succession. Previously, six 3rd-order depositional sequences (C1 to C6) have been recognized and frequently used as ...regional time slices. Recent research, however, indicates a need for revision and additions, including the recognition of additional 3rd- and 4th-order sequences. We propose amendments based upon high-resolution correlations using a combination of regional disconformities, cycle stacking patterns, bioevents, marker beds, and chemostratigraphy. Several disconformities, including a large regionally angular mid-Richmondian unconformity, are newly recognized or reinterpreted. In addition, distinctive depositional patterns aid in the recognition of systems tracts, with a) thick proximal laminated peritidal facies representing early transgressive systems tracts (TSTs) or lowstands, in part (LSTs), b) shell-rich limestone packages representing later TSTs and overlain by c) more shale-prone highstand systems tracts (HSTs), themselves overlain locally by d) siliciclastic dominated falling stage systems tract (FSST) deposits that are commonly removed beneath substantial unconformities (sequence boundaries). At present, we recognize eight 3rd-order Cincinnatian sequences, designated C1 through C8, and 16 4th-order subdivisions and their component systems tracts. A younger (Hirnantian?) sequence may be present at some localities as the enigmatic Centerville Formation and/or basal Belfast Member of the Brassfield Formation. The implications of these new correlations and sequence interpretations include a new standard for relative sea-level changes and insights into basin dynamics. This framework also permits a more nuanced history of biotic changes that include geologically brief pulses of immigration associated with the transgressions of the C1 (lower Kope Formation), C5C (Clarksville Member of Waynesville Formation), and C7A (basal Whitewater Formation).
•Synthesis of Upper Ordovician (Cincinnatian) litho- and biofacies patterns•Revised model of cratonic, mixed siliciclastic‑carbonate sequences presented•Existing sequence stratigraphic framework for the Cincinnatian is strongly revised.•New framework recognizes 8 third-order and more than 16 fourth order sequences.•Provides new insights into temporal patterns of physical and biotic events
Species migration events are common features of the fossil record, but the impacts of immigration events vary. In this paper, the pattern and impact of two types of immigration events are compared: ...ephemeral invasion and biotic immigration events (BIMEs). Specifically, this study focuses on biotic patterns preserved in Edenian, Maysvillian, and Richmondian (Late Ordovician, Katian) age strata in the Cincinnati, USA region. New Edenian occurrences of rhynchonelliformean brachiopod taxa belonging to the classic “Richmondian Fauna” are documented, and the ecological and evolutionary impacts of these short-lived pre-Richmondian invasions and the sustained Richmondian Invasion are compared. The Richmondian Invasion produced substantial ecological changes and evolutionary impacts within the Cincinnatian paleocommunity; however, the ephemeral invasions that occurred in the Kope Formation did not produce a marked or lasting impact on ecological relationships within Cincinnatian paleocommunities. In each instance, an Edenian novel immigration or biotic event was limited in temporal duration and did not exceed the time to deposit a single sedimentary package. Although such ephemeral invasions do not result in community-scale changes, they nevertheless provide important information about basin connectivity, provide insight into abiotic environmental conditions, and can be useful stratigraphic indicators.
Hardgrounds from the Upper Ordovician strata of eastern Laurentia exhibit a wide range of morphologies, though the development of their complex surface topographies remains poorly understood. These ...early lithified seafloors, which can be laterally very extensive, may provide key information about basin dynamics and global ocean fluctuations. Based on spectacular exposures and newly-excavated material, we examined a suite of hardgrounds from the Upper Ordovician (Katian) of southern Ontario and the Cincinnati Arch region and documented the processes of genesis, development, and modification of simple, complex, and block hardgrounds. In this study, we used extensive field work, petrology, and cathodoluminescence to determine the evolution and shaping of hardgrounds as a result of intense submarine erosion and prolonged exposure of these surfaces and reveal a progression from simple to complex hardgrounds and ultimately to isolated cobble- to boulder-sized block hardgrounds. We survey the distribution of hardgrounds in a sequence stratigraphic framework to determine allocyclic controls on hardground development, highlight the important role that mixed siliciclastic-carbonate environments play in promoting the development of heterogeneous hardground topographies, and analyze the effects of high surface reliefs on local depositional and erosional regimes. In addition, we interpret the impact of increasingly abundant complex hardgrounds throughout the Ordovician on hard-substrate community diversification and their contribution to the Great Ordovician Biodiversification Event. We also discuss time-specific aspects of the Late Ordovician that made it a peak interval of hardground proliferation.
•Upper Ordovician hardgrounds have been studied from the eastern U.S. and Canada.•Complex hardground morphologies are controlled by extended exposure and erosion.•Block hardgrounds may result from erosion of lenticular beds or complex hardgrounds.•Complex hardgrounds indicate periods of sediment starvation and negative sedimentation at key sequence stratigraphic surfaces.•Heterogeneous hardground habitats promote the recruitment of diverse encrusting communities.
Based on δ13C data from two drillcores recovered from the Siljan district, we present a first continuous carbon isotope record of the upper Tremadocian–lower Katian limestone succession of central ...Sweden. New names for some isotopic carbon excursions from the Cambrian–Ordovician boundary through the basal Darriwilian are introduced. The Mora 001 core from the western part of the Siljan impact structure ranges through the Lower–Middle Ordovician, whereas the Solberga 1 core from its eastern part ranges through the Middle–lower Upper Ordovician. Upper Tremadocian and Floian units are extremely condensed and include extensive stratigraphic gaps. Multiple hardgrounds, sometimes with minor karstic overprint, imply recurrent periods of erosion and/or non-deposition. Like in other parts of Sweden, the Dapingian and Darriwilian succession is characterized by a relatively complete sedimentary record and low sedimentation rates.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, ODKLJ, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
A large colonial rugose coral was recently discovered as float partially buried beneath several inches of sediment in the Kope Formation of northern Kentucky. Corals are unreported in the Kope ...assemblage, not appearing until much later during the C4 and C5 sequences during the Richmondian Invasion, a period in which the area was inundated with invasive taxa migrating from the midcontinent. The slab contains the remains of several other species that are diagnostic of the Kope Formation, such as the brachiopods Sowerbyella rugosa and Zygospira cincinnatiensis. The large colonial rugose coral is composed of corallites ranging in diameter from 3 to 5 mm containing 10–14 twisting major septa with crenulated walls, which is consistent with Cyathophylloides cf. C. burksae.
New taxa or new occurrences in a well-sampled formation, such as the Kope Formation, are unexpected especially for large skeletonized taxa, and highlights the rarity of coral within the assemblage. The Richmondian Invasion is linked to a transgressive event that increased connectivity between marine biogeographic provinces, disrupted ecosystem structure as well as acted as a significant evolutionary driver during the late Ordovician in the Cincinnatian faunal assemblages. Isolated dispersal events may have brought planktonic larva onto the Cincinnati Arch much earlier during transgression in the C1 sequence. The failure of the coral to become established might be linked to the low abundance of larva entering the region or non-ideal environmental conditions. The discovery of this coral in the Kope Formation further indicates the occurrence of rare and ephemeral dispersal events that have recently been reported within brachiopods.
•Colonial coral are rare, but occur within the Ordovician Kope Formation.•Their presences highlight multiple faunal invasions prior to the Richmondian.•The colony size suggests low larval abundance resulted in the failed invasion.•Paleobiogeography can clarify the factors that determine the fate of an invasion.
The major glaciation at the end of the Ordovician is associated with the 2nd largest mass extinction event of the Phanerozoic. Growth of Late Ordovician ice sheets requires a dramatic cooling from ...the ‘greenhouse’ conditions that prevailed for most of the Ordovician, but when and how fast this cooling occurred are controversial issues. The controversy is due in large part to a lack of good geochemical constraints on the temperature history of the Katian (453–445.2Ma). To address this uncertainty, we measured phosphate δ18O values from 3 conodont species collected from sections in the midcontinent region of the United States that span an ~5.7m.yr. long interval covering most of the Katian. Results reveal a statistically significant offset in δ18O values between some taxa and show up to 2‰ differences among samples. However, there are no apparent long-term trends within or between sections; rather, values fluctuate around a δ18O mean of ~19‰ VSMOW. Our study provides the longest, relatively high resolution, species specific conodont record generated for this interval, and we found no evidence supporting progressive cooling during the Katian.
•The δ18OVSMOW values of Katian conodonts fluctuate around 18.9‰.•There is no evidence of cooling or glaciation during the sampled ~5.7m.yr. interval studied.•Temperatures remained relatively constant throughout most of the Katian.•Glaciation began either prior to the Katian or during the Hirnantian.•Statistically significant offset exits in δ18O for the conodont taxa analyzed.
Skeletal concentrations in mudstones may represent local facies produced by storm winnowing in shallow water, or time-specific deposits related to intervals of diminished sediment supply. Upper ...Ordovician (Katian) of the Cincinnati region is a mixed siliciclastic-carbonate succession including meter-scale cycles containing a shelly limestone-dominated phase and a mudstone-dominated phase.
The “tempestite proximality model” asserts that shell-rich intervals originated by winnowing of mud from undifferentiated fair-weather deposits. Thus shell beds are construed as tempestites, while interbedded mudstones represent either fair-weather or bypassed mud. Meter-scale cycles are attributed to sea-level fluctuation or varying storm intensity.
Alternatively, the “episodic starvation model” argues, on the basis of petrographic, taphonomic, and stratigraphic evidence, that, despite widespread evidence for storms or other turbulence events (e.g. tsunamis), winnowing alone could not generate shell beds where none had previously existed. Instead, variations in sediment supply are construed as the principal cause of shelly-mudstone cycles. Shell-rich deposits accrue during periods of siliciclastic sediment starvation and relatively shell-free mud accumulates during periods of sediment influx.
Tempestite proximality and episodic starvation models lead to contrasting predictions about proximal-to-distal facies patterns. These are: (i) large versus small volumes of distally-deposited, bypassed mud; (ii) proximal grainstones and distal packstones versus distal grainstones and proximal packstones; and (iii) proximal versus distal amalgamation and condensation of shell beds.
In this paper, these predictions are tested by (i) comparing meter-scale cycles from different horizons and depositional environments through the lower Cincinnatian succession (Kope through McMillan Formations representing deep subtidal through intertidal environments), and (ii) correlating intervals and individual meter-scale cycles from the Fairview Formation of the Cincinnati Arch (shallow subtidal) north and west into the Maquoketa Shale (deep subtidal) in subsurface of Ohio and Indiana. Both approaches show patterns consistent with episodic starvation, not winnowing, including: (i) small differences in stratigraphic thickness indicate small volumes of bypassed mud; (ii) discrete distal deep-water grainstones that splay proximally into bundles of thinner shallow-water packstones alternating with shelly muds show that grainstones formed from a lack of, rather than removal of mud; and (iii) distal shell‐bed amalgamation and condensation (and corresponding proximal splaying) of shell beds shows a proximal source of mud.
Thus, winnowing by storms or other turbulence events did not generate shell beds or cycles from undifferentiated sediments despite abundant evidence for storm deposition. High-resolution correlations imply that the shell-bed and mud-bed hemicycles reflect simultaneous basin-wide changes in sedimentary style rather than contemporaneous facies belts that track sea level. In this sense, shell-rich and mud-rich hemicycles are “non-Waltherian” facies.
► Cycle correlation in Cincinnatian supports condensation origin for shell beds. ► Storms altered shell beds and muds, but did not generate them. ► Limestone and mudrock phases of m-scale cycles are independent depositional systems. ► Limestones fan out proximally, not distally. ► Grainstone is more characteristic of deep-water than shallow-water environments.
The effect of ripening time on the microstructural, physicochemical and rheological characteristics of traditional Kope cheese ripened in clay pots was investigated. The moisture content, pH and ...total nitrogen (TN)/dry matter (DM) of the cheese decreased, and DM, fat in DM and water‐soluble nitrogen/TN increased during this period. Storage and loss moduli increased, while loss tangent decreased; as a result, the elasticity characteristics were greater than the viscous characteristics of the samples. Microstructure images showed that the size of pores and casein network density increased significantly during ripening and, after 90 days, the structure of many pores became very similar to each other.
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