Physical Stratigraphy Research Articles

Petrography, Diagenesis, and Depositional Setting of Glenn (Bartlesville) Sandstone, Berryhill Unit, Glenn Pool, Oklahoma: ABSTRACT

Petrography and physical stratigraphy of the (Bartlesville) sandstone in the 160-acre Berryhill unit, Glenn Pool, were established from 10 cores and more than 60 modern well logs. The reservoir mostly is sublitharenite to litharenite; lithic constituents chiefly are metamorphic rocks and rip-up clasts. Principal diagenetic minerals are kaolinite, chlorite, and illite. This evidence and data from the regional and local stratigraphic framework indicate that sands were upper delta-plain deposits. Logs of the closely spaced wells show moderately complex short-distance change in geometry of the sandstone and attendant reservoir heterogeneity. All this information is integral in ongoing plans for enhanced recovery and in current research on enhancement of well logs by s gnal processing. End_of_Article - Last_Page 498------------

Glacial and Postglacial Physical Stratigraphy and Chronology, North Willow Creek and Cataract Creek Drainage Basins, Eastern Tobacco Root Range, Southwestern Montana, U.S.A.

Glacial and Postglacial Physical Stratigraphy and Chronology, North Willow Creek and Cataract Creek Drainage Basins, Eastern Tobacco Root Range, Southwestern Montana, U.S.A.

Glacial and Postglacial Physical Stratigraphy and Chronology, North Willow Creek and Cataract Creek Drainage Basins, Eastern Tobacco Root Range, Southwestern Montana, U.S.A.

Glacial and Postglacial Physical Stratigraphy and Chronology, North Willow Creek and Cataract Creek Drainage Basins, Eastern Tobacco Root Range, Southwestern Montana, U.S.A.

Neogene Vertebrate Paleontology and Stratigraphy of Nepal

ABSTRACT
 For the past 150 years, the Siwalik Group, a Miocene through Pleistocene molasse along the flank of the Himalaya has been studied intensively stratigraphically and paleontologically in both India and Pakistan. This work recently has been extended into Nepal, where a presumably complete Siwalik section is present, and a modest number of vertebrate fossils have been found. All but one of Nepalese Siwalik vertebrates hare been collected along the southern edge of the Dang Valley in western Nepal. Two assemblages are now known. The older is of presumed Miocene age and likely equivalent to the fauna of the Chinji Formation in Pakistan. The other is of late Pliocene to early Pleistocene age and similar to the Indian Pinjor fauna.
 In addition, Plio-Pleistocene vertebrates have been reported from fluvial intermontane deposits in the Kathmandu Valley.
 As studies of radiometric dating, magnetostratigraphy, physical stratigraphy and fossil distributions are extended into Nepal, the place of the Nepalese Siwaliks and basin deposits will become increasingly clear.

Early acquisition of characteristic magnetization in red beds of the Moenkopi Formation (Triassic), Gray Mountain, Arizona

Four discrete magnetizations associated with events occurring during deposition, early diagenesis, recent weathering, and cloud to ground lightning have been identified in rocks of the Moenkopi Formation at Gray Mountain, Arizona. A paleomagnetic study of more than 800 samples tied closely to the physical stratigraphy of the Moenkopi indicates that most of the magnetization remaining after partial alternating field and thermal demagnetization was acquired during and shortly after deposition. Directions of this remaining (characteristic) magnetization, in both normally and reversely magnetized rock, are closely similar to directions reported for the Moenkopi elsewhere on the Colorado Plateau. Sampling across the Moenkopi Formation at Gray Mountain has revealed two reversed magnetozones separating three normal magnetozones. Generally sharp boundaries of the magnetozones, their close concordance with physical stratigraphic units, and the rarity of anomalous directions of magnetization within the magnetozones indicate that most of the secondary components of the characteristic magnetization were acquired within 104–105 years after deposition. A conglomerate test based on siltstone clasts in sandstone shows highly scattered but not completely random directions of magnetization following partial thermal demagnetization. A secondary Triassic normal magnetization appears to be superimposed on some of the clasts, as suggested by the approximate coincidence of the resultant magnetic vector from the clasts with a Triassic normal direction. A fold test based on samples from highly deformed silty clay stone and sandstone in an intraformational landslide shows that these rocks acquired most of their stable magnetization before folding. A component of Triassic normal magnetization acquired after deformation also occurs in some of these rocks.

Craters as “fossils”: The remote dating of planetary surface materials

The need to determine relative ages of materials and surfaces on moons and planets other than the Earth has resulted in the development of dating techniques that are based on the density or the morphology of craters and that supplement the classical techniques of physical stratigraphy. As is the case with the fossil-based relative time scale on Earth, crater-based relative ages can, in principal, be calibrated with radiometric ages of returned samples. Relative ages determined by crater density or crater morphology rest on a small number of basic assumptions concerning the morphology of fresh craters, the randomness of crater-formation processes, and the rates and areal constancy of crater-degradation processes. The validity of these assumptions varies from planet to planet. Despite the problems and controversies that inevitably accompany the development of major new techniques, the basic principles underlying the use of craters to determine relative ages are well established and logically sound.

Middle Devonian Bentonite in Michigan Basin: DISCUSSION

We agree with Baltrusaitis that the thin bentonite bed that he has described as the Kawkawlin Bentonite in the Michigan basin and the Tioga Bentonite Bed that others have described in New York and in the Appalachian and Illinois basins represent one and the same ashfall. However, contrary to his view, we believe that the bentonite bed described by Droste and Vitaliano on the flank of the Michigan basin in northern Indiana is also the Tioga and thus is equivalent to the Kawkawlin. The relations of the northern Indiana bentonite bed to standard conodont zones, the bed's position in a Middle Devonian physical stratigraphy thoroughly studied throughout Indiana, and the mineralogy and petrography of the bentonite all seem to indicate that the northern Indiana bentonite should not be considered as a lower (than Tioga and Kawkawlin) bentonite that would have no known equivalent elsewhere.

Correlation and Paleogeography of Upper Part of Helderberg Group (Lower Devonian) of Central Appalachians

Physical stratigraphy and environmental relations in the upper part of the Helderberg Group have clarified the interpretation of biostratigraphic data in a previously enigmatic area of Appalachian Lower Devonian correlation. The Licking Creek Limestone, a marine carbonate shelf facies, is subdivided and its members (lower, Cherry Run Member; upper, Little Cove Member) are traced along the eastern outcrop belt from south-central Pennsylvania southward to central Virginia. Toward the northwest the Cherry Run increases in thickness and intertongues with the lower two thirds of the Shriver Chert, an offshore calcareous cherty silt and mud which occupies the depositional basin axis. The Little Cove rises stratigraphically toward the northwest and is traced into the upper part f the Shriver Chert. Lithologic and faunal differences of the equivalent units are caused by the differing, but time-equivalent, adjacent environmental settings (shallow shelf-basin axis). Lithostratigraphic evidence indicates that the upper contact of the Licking Creek-Shriver strata rises in the section in a northwesterly (basinward) direction and that the Licking Creek of the eastern outcrop belt intertongues with the lower two thirds of the Shriver in its type area. Biostratigraphic evidence indicates that faunal elements are added to the upper part of this interval as the contact rises. This evidence also suggests that the Licking Creek of the eastern outcrop belt and the lower two thirds of the Shriver are Helderbergian and the upper third of the Shriver is Deerparkian. Paleogeographic reconstruction of these correlations shows that (1) shoreline and facies boundaries are slightly oblique to the outcrop belt; (2) shallow carbonate facies tended to migrate westward (basinward) during this time, indicating a regressive trend just prior to Oriskany Sandstone deposition; and (3) the basin margin pre-Oriskany unconformity does not extend over large areas of the depositional basin itself. These conclusions are of potential significance for gas exploration in the upper Helderberg and overlying Oriskany Sandstone in relating subsurface stratigraphic facies and structure to the observed surface trends and correlations.

Petroleum Related to Middle and Upper Devonian Deltaic Facies in Central Appalachians

Strata of the Devonian subaerial and prodelta complex are preserved in 110,000 sq mi (260,000 sq km) of the Appalachian basin. Petroleum is obtained only from the western half, principally from higher permeability marine sandstones, although some is from prodelta dark shales. Absence of production in the east presumably is due to the escape of hydrocarbon from folds which bring potential reservoir strata to outcrop level. Outcrops along the Allegheny Front from Maryland to Virginia were studied to interpret physical stratigraphy and environments of deposition and to understand better the factors controlling petroleum occurrence. The deltaic clastic sediment came from an eastern quartzose source located in latitude from New York to Virginia. Depositional patterns of petroliferous sands resulted from gradual infilling of a subsiding basin, interrupted by rather abrupt eastward transgressions, which produced nearly synchronous, winnowed sands traceable across many counties. The earliest prodelta (Needmore Shale of Onesquethaw Stage) was derived from an upland near Baltimore. Cazenovia Stage deltaic siltstones and sandstones accumulated in Pennsylvania and New York. In late Tioughnioga time the winnowing zone extended to West Virginia (Clearville Siltstone) while terrestrial redbeds were accumulating in the Catskill Mountains. Early in the Taghanic, hundreds of feet of eustatic sea level rise shifted the shorelin scores of miles eastward. Throughout the rest of the Late Devonian the shoreline prograded generally westward, with fairly sudden eastward shifts of tens of miles during times of eustatic sea level rise. Younger petroliferous sandstones of the Cassadaga and Bradford stages accumulated in the western part of the basin during winnowing that accompanied shoreline shifts. Maximum westward encroachment of the subaerial Catskill delta was during Bradford times, followed by Early Mississippian transgression which produced Pocono Group sandstones. Eustatic sea level changes leave sedimentary imprints which should be traceable for long distances in shallow marine sediments. Specific correlations from Virginia to New York are developed by matching times of sea level fluctuation.

Petroleum Related to Middle and Upper Devonian Deltaic Facies in Central Appalachians: ABSTRACT

Strata of the Devonian subaerial and prodelta complex are preserved in 110,000 sq mi (260,000 sq km) of the Appalachian basin. Petroleum is obtained only from the western half, principally from higher permeability marine sandstones, although some is from prodelta dark shales. Absence of production in the east presumably is due to the escape of hydrocarbon from folds which bring potential reservoir strata to outcrop level. Outcrops along the Allegheny Front from Maryland to Virginia were studied to interpret physical stratigraphy and environments of deposition and to understand better the factors controlling petroleum occurrence. The deltaic clastic sediment came from an eastern quartzose source located in latitude from New York to Virginia. Depositional patterns of petroliferous sands resulted from gradual infilling of a subsiding basin, interrupted by rather abrupt eastward transgressions, which produced nearly synchronous, winnowed sands traceable across many counties. The earliest prodelta (Needmore Shale of Onesquethaw Stage) was derived from an upland near Baltimore. Cazenovia Stage deltaic siltstones and sandstones accumulated in Pennsylvania and New York. In late Tioughnioga time the winnowing zone extended to West Virginia (Clearville Siltstone) while terrestrial redbeds were accumulating in the Catskill Mountains. Early in the Taghanic, hundreds of feet of eustatic sea level rise shifted the shorelin scores of miles eastward. Throughout the rest of the Late Devonian the shoreline prograded generally westward, with fairly sudden eastward shifts of tens of miles during times of eustatic sea level rise. Younger petroliferous sandstones of the Cassadaga and Bradford stages accumulated in the western part of the basin during winnowing that accompanied shoreline shifts. Maximum westward encroachment of the subaerial Catskill delta was during Bradford times, followed by Early Mississippian transgression which produced Pocono Group sandstones. Eustatic sea level changes leave sedimentary imprints which should be traceable for long distances in shallow marine sediments. Specific correlations from Virginia to New York are developed by matching times of sea level fluctuation.

Space-time relations of Cenozoic silicic volcanism in the Great Basin of the western United States

Physical stratigraphy and more than 250 K-Ar dates demonstrate a definite space-time pattern of Cenozoic silicic volcanism in the Great Basin. Known vent areas of voluminous ash flows and approximate source areas for sheets provide the control points. Volcanism began about 40 m.y. ago and volcanic rocks are most abundant in east-central Nevada. The locus of activity then shifted outward toward the margins of the Great Basin. Silicic activity ceased in east-central Nevada about 25 m.y. ago and by 20 m.y. ago was restricted to the margins of the basin. Intensity has decreased progressively for the last 10 m.y. East-central Nevada is less seismic and possibly has a thicker crust than the rest of the basin. The outward migration of volcanism may have been the result of convection within the mantle with a rising current centered on the east-central part of the Great Basin.

Late Cenozoic Crustal Movements in the Sierra Nevada of California

The geometry of the late Cenozoic uplift of the Sierra Nevada is determined from the record of Tertiary river channels and volcanic rocks and from gross physiography of the range. This geometry is described by means of a structure contour map. Fossil mammals, some spore-pollen data, physical stratigraphy, K-A dates, and physiography indicate that the last major uplift began during Pliocene time and that the eastern escarpment developed subsequently by downfaulting of the area to the east. The simple geometry of movements over a large area in the Sierra Nevada, contrasted with the complex pattern of movements to the east and west during the same interval, seems likely to be a direct expression of processes that have produced crustal material during the rise of the Sierra.

Space, Things, Time, and Events--An Essay on Stratigraphy

This paper is an attempt to analyze meaning of basic concepts of stratigraphy. It is, by its very nature, personal and subjective interpretation, even if throughout whole essay deliberate effort has been made to maintain an objective and unbiased attitude and rigorous and exacting method in analysis of somewhat complex problems involved. The first part of essay deals with concepts of stratigraphy, space, locality, material things, formations, time, events, simultaneity, and succession. This part lays down basis, and states premises, on which second part of essay is built up by simple process of deductive reasoning. The fundamental premises set forth are: (1) stratigraphy is the study of shape, dimensions, and spatial relations of of and of space-time relations of which of represent; (2) bodies of rock or formations are purely three-dimensional material things divorced from idea of time; (3) means both date and duration, first concept being fundamental one, as second concept can be expressed n terms of first one, whereas reverse is not true; (4) is system of imaginary infinitesimal world-wide instants in space-time continuum, constituting kind of frame in which we locate of external world; (5) of geology are happenings in external world; (6) there are two kinds of events: instantaneous and (7) bodies of rock, though purely material things, are record of past lithogenetic flow and (8) time relationships between lithogenetic flow can be classed as simultaneous, partly simultaneous, successive, or subsequent. The second part of essay deals essentially with concepts of correlation, time-table, key-events, relationship between stratigraphy and zones, stages, time-rock units, and time-units. A strict deductive reasoning, based on premises set forth in first part of essay, leads me to conclude that (1) means the establishment of temporal relations between and that this can only be achieved indirectly, by means of linking connecting unrelated events; (2) geological is tabular statement of chronological order in which took place; (3) key-events of time-table are and (4) we can correlate se imentary flow represented by of rocks with unrelated paleontological of time-table only by means of linking event: fossil content of of rock. This leads naturally to regard zones as events of historical paleontology, and to define as the life-range of or of group of associated species, and to accept Oppel's definition of as grouping of However, same deductive reasoning shows that present concept of stage transcends Oppel's definition and has developed into correlation concept, with net result that is now conceived as image of a dynamic as opposed to mere association of static species in successive zones. A as correlation concept, is recorded life range of whole dynamic fauna, which though diversified in phyla and classes, unevenly distributed in space and time, and undergoing changes with passing of time, yet forms coherent whole, congruent totum characterized by state of evolution once given and never repeated. Both concepts, those of and stage, are, therefore, concepts of historical paleontology and not concepts of historical stratigraphy. Pursuing subject further, same deductive thinking leads me to conclusion that what many stratigraphers call time-rock units are, in truth, zone event-stratigraphical units, i.e., concept that ties together number of past through their results (rocks), with given event, also through its results (fossils). And pushing argument still further, to its ultimate end, I see no intrinsic difference between so-called time-units and paleobiological To my way of thinking, Tremadocian Age and Tremadocian Stage, for instance, are interchangeable expressions, because both concepts are based not on pure time, but on succession of paleontological events. To summarize this abstract: physical stratigraphy is science that deals with spatial relationship of material things; historical stratigraphy deals with spatial and temporal relationships of events.

Response Model Design for a Rhythmic Delta-Platform Domain, Devonian Catskill Complex of New York: ABSTRACT

Investigation of the physical stratigraphy of the Middle and Upper Devonian of southeastern New York has shown that this sequence of the Catskill Deltaic Complex might be separated naturally into a set of sedimentary domains. The North Point (lowermost Upper Devonian), one of these domains, is characterized by rhythmic patterns in sediment color, texture, and petrology; sedimentary structures; sediment transport directions; lithologic sequences; and lithosome geometries. The rhythmically recursive sequence of the North Point consists of (in ascending order): (A) polymictic conglomerate, (B) gray conglomeratic subgraywacke, (C) gray subgraywacke, (D) red subgraywacke, (E) red siltstone, (F) red mudrocks, (G) olive mudrocks, (H) gray mudrocks, and (I) sub-protoquartzite. Various physical and statistical models of source, distribution, accumulation, and modification realms of the process-response system of the North Point were simulated on an electronic computer. The algorithm for a model of the process-response system of a rhythmic sequence, obtained by integration of relative aspects of these models, may be approximated by six sub-sets of equations; each sub-set is an attempt to characterize the status of process elements in the development of a response phase. Translated into operational format these phases are: (1) early regressive phase (units A, B,); (2) middle regressive phase (B, C); (3) late regressive phase (D, E); (4) paralic stability phase (E, F); (5) early transgressive phase (G, H); and (6) late transgressive phase (H, I). The general aspect of this model is coarse-grained sediments (A, B, C) passing upward into finer sediments (E, F, G, H), forming a platform sequence which is rhythmically recursive. Homogenization at the strand zone and re-organization on the distal portion of the platform produces an inverted sequence (fines grading upward to coarser units). This model recognizes two components of subsidence, local and regional, as dominant process elements of the accumulation realm. The regional component is decomposed into he effects produced by compaction of the underlying sediment pile and those produced by subsidence of the Devonian sub-basin. The local component results from surface and near-surface compaction of sediment deposited during phases 3, 4, and 5 (units E, F, G, H) of a rhythmic sequence. The algebraic sum of the interaction of these two process elements may have profound effects on the character and mode of the response, producing transgression in one part of the domain, while regression or stability characterizes another part. Within the framework of this model the rhythmic character of the North Point is thought to be the response to the interaction of: (1) source contribution activity; (2) design of transport and dispersal systems; (3) influence of sub-basin and platform dynamics on the character and mode of the accumulation; (4) modification of the accumulation by processes such as compaction, erosion, diagenesis, and structural adjustments. End_of_Article - Last_Page 336------------

Physical Stratigraphy

It is proposed to discuss the physical aspects of the stratigraphy before entering into a discussion of the cultural remains of the Cattle Point site. The reasons for this are manifold. First, the differentiation of the strata on a purely physical basis will give us some idea of the different occupations of the site. Second, the widely differing nature of the layers offers some opportunity of dating the cultural remains in terms of strata which show time and content differences. Third, the shell and animal remains of the strata provide still another basis for differentiating the archaeological remains of the site. These reasons, and many more which will come out in the following discussion, serve as adequate cause for considering the physical aspects of the strata before the cultural.In the three main areas of the site which were excavated we find distinct stratification. There exists a correlation between all three areas of the site as well.

Physical Stratigraphy

The accompanying Figure 26 was made by the writer from Newell's field notes and profiles. These profiles summarize the potential stratigraphy within the excavated leg of the mound in terms of the actual sequence of construction. (All remarks hereafter on the construction of “the mound” must be taken to apply only to the excavated eastern leg, subject to possible correction if and when the other leg is examined.) It will be shown that not all these stages of construction have determinable cultural significance; that is, some show no apparent differences in the associated cultural material and can be grouped into what we shall call “phases” of occupation.The reader should first examine NewelFs contour map of the site (Fig. 4), showing the peculiar L-shape of the complete mound, the grid system of numbered squares, and the position of the numerous house outlines.