Stratigraphy Commons^™

The Global Stratotype Section And Point (Gssp) For The Base Of The Katian Stage Of The Upper Ordovician Series At Black Knob Ridge, Southeastern Oklahoma, Usa, Daniel Goldman, Stephen A. Leslie, Jaak Nõlvak, Seth Young, Stig M. Bergström, Warren D. Huff

Department of Earth, Environment and Sustainability Faculty Publications

The International Subcomission on Ordovician Stratigraphy (ISOS) of the International Commission on Stratigraphy (ICS) recently defined the base of the global Upper Ordovician Series to be at the first appearance datum (FAD) of the graptolite species Nemagraptus gracilis in the Fågelsång GSSP in southern Sweden. This designation recognized the tremendous utility for global correlation of the first appearance of a cosmopolitan taxon that occurs within a consistent succession of other first appearance datums (e.g., Finney and Bergström, 1986; Bergström et al., 2000). Current efforts by the ISOS have focused on subdividing the Upper Ordovician into three stages and choosing appropriate …

Condensed And Expanded Sections In The Lower Mesaverde Clastic Wedge, Campanian Of Wyoming: Evidence For Tectonic Rectification Of Sea Level, Matthew W. Botzler

OES Theses and Dissertations

The stratigraphy of the Cretaceous Western Interior basin indicates that sea level oscillated during the late Cretaceous. The oscillations were polyharmonic, with periods ranging from millions of years to hundred thousands and ten thousands of years. However, there is disagreement over the extent to which sea level change was global in nature and the extent to which it was driven by local uplift or subsidence (tectonism). In orogenic regions where subsidence, sediment supply, and eustatic variation are all affecting sea level, comparisons of high and low frequency cycles can help to sort out forcing mechanisms. Low frequency eustatic sea level …

Mapping Of A Detachment Fault In Kythera Island And Study Of The Related Structural Shear Sense Indicators, Antonios Marsellos

Geology Theses and Dissertations

Kythera Island is located on the prominent submarine horst between Crete and the Peloponnese in the southwestern part of the Aegean. The structure of Kythera is characterized by a pile of tectonic slices derived from different paleogeographic zones. The upper unmetamorphosed units comprise pelagic limestones and cherts of Pindos zone emplaced by thrusting in the Eocene on top of Tripolis zone neritic limestones. These units are separated from the lower metamorphosed unit of Phyllite-Quartzite (PQU) exposed in the northern part of Kythera by an extensional detachment fault of Late Miocene age. The lower tectonic unit of PQU was affected by …

Prevailing Weather Conditions During Summer Seasons Around Gangotri Glacier, Pratap Singh, Umesh K. Haritashya, K. S. Ramasastri, Naresh Kumar

Department of Earth, Environment and Sustainability Faculty Publications

Meteorological data collected near the snout of the Gangotri Glacier suggest that the study area receives less rainfall. The average seasonal rainfall is observed to be about 260 mm. The rainfall distribution does not show any monsoon impact. Amount of seasonal rainfall is highly variable (131.4-368.8 mm) from year to year, but, in general, August had the maximum rainfall. A verage daily maximum and minimum temperatures were 14.7 and 4.1°C respectively, whereas average mean temperature was 9.4°C. July was recorded as the warmest month. During daytime, wind speed was four times higher than that at night-time. The average daytime and …

Source Of Meta-Igneous Blocks And Structure Of The Colebrooke Schist In The Snowcamp Peak Area, Pickett Peak Terrane, Southwestern Oregon, Jennifer Katrib

Geology Theses and Dissertations

The Colebrooke Schist of the Pickett Peak terrane, southwestern Oregon, is the easternmost, structurally highest unit of the Late Mesozoic-Cenozoic Franciscan Accretionary Complex. The Colebrooke Schist consists of mostly transitional greenschist-blueschist-facies meta-sedimentary rocks with common blocks of meta-volcanics and serpentinites, rare talc-schists and meta-plutonic rocks. The Colebrooke Schist meta-volcanic blocks are greenstones, in many cases with visible relict pillow structures and relict igneous textures.
Fifteen meta-volcanic samples and one meta-plutonic sample were analyzed by XRF and ICP-MS and were plotted with analyses from Plake (1989) and Coleman (1972). The Colebrooke Schist meta-volcanic rocks plot in mid-ocean ridge basalt (MORB), island …

Transition From Contraction To Extension In The Northeastern Basin And Range: New Evidence From The Copper Mountains, Nevada, Jeffrey M. Rahl, Allen J. Mcgrew, Kenneth A. Foland

Department of Earth, Environment and Sustainability Faculty Publications

New mapping, structural analysis, and 40Ar/39Ar dating reveal an unusually well‐constrained history of Late Eocene extension in the Copper Mountains of the northern Basin and Range province. In this area, the northeast‐trending Copper Creek normal fault juxtaposes a distinctive sequence of metacarbonate and granitoid rocks against a footwall of Upper Precambrian to Lower Cambrian quartzite and phyllite. Correlation of the hanging wall with footwall rocks to the northwest provides an approximate piercing point that requires 8–12 km displacement in an ESE direction. This displaced fault slice is itself bounded above by another normal fault (the Meadow Fork Fault), which brings …

Quartzite Fabric Transition In A Cordilleran Metamorphic Core Complex, Allen J. Mcgrew, Martin Casey

Department of Earth, Environment and Sustainability Faculty Publications

Photomicrographs 143A-143F record fabric variations in quartzite with increasing structural depth in a > 1 km thick, amphibolite-facies, normal-sense shear zone in the East Humboldt metamorphic core complex, Nevada (Figure 143.1). This shear zone and the overlying detachment system unroofed an infrastructure of high-grade, migmatitic gneiss during Oligocene to early Miocene extension (Dallmeyer and others, 1986; Wright and Snoke, 1993; McGrew and Snee, 1994). Thermobarometric constraints from near the base of the mylonitic zone record deformation conditions of 550°- 620°C and 300-400 MPa (Hurlow and others, 1991). Sample WBC6 (l43A and 143B) characterizes the mylonitic zone, whereas sample 8706-1 (143C and …

Grand Tour-Part 2: Petrogenesis And Thermal Evolution Of Deep Continental-Crust: The Record From The East Humboldt Range, Nevada, Allen J. Mcgrew, Mark T. Peters

Department of Earth, Environment and Sustainability Faculty Publications

The northern part of the East Humboldt Range, Nevada, provides a rare opportunity to explore the petrogenetic environment of deep levels in the middle crust during both large-scale Mesozoic contraction and Cenozoic regional extension. On this segment of the field trip, we will explore evidence bearing on the character of the metamorphic and magmatic history of this terrane, and attempt to link these constraints to the rheology and tectonic evolution of the middle crust during the Mesozoic and Cenozoic.

The Grand Tour Of The Ruby-East Humboldt Metamorphic Core Complex, Northeastern Nevada: Part 1-Introduction & Road Log, Arthur W. Snoke, Keith A. Howard, Allen J. Mcgrew, Bradford R. Burton, Calvin G. Barnes, Mark T. Peters, James E. Wright

Department of Earth, Environment and Sustainability Faculty Publications

The purpose of this geological excursion is to provide an overview of the multiphase developmental history of the Ruby Mountains and East Humboldt Range, northeastern Nevada. Although these mountain ranges are commonly cited as a classic example of a Cordilleran metamorphic core complex developed through large-magnitude, mid-Tertiary crustal extension, a preceding polyphase Mesozoic contractional history is also well preserved in the ranges. An early phase of this history involved Late Jurassic two-mica granitic magmatism, high-temperature but relatively low-pressure metamorphism, and polyphase deformation in the central Ruby Mountains. In the northern Ruby Mountains and East Humboldt Range, a Late Cretaceous history …

Stratigraphy And Structure At The Southern End Of Lake Champlain In Benson, Vermont, Jennifer L. Granducci

Geology Theses and Dissertations

Detailed mapping and structural investigations in an area bound to the west by the Grenvillian basement of the Adirondack Mountains and to the east by the allochthonous slates of the Taconic Mountains led to the distinction of a Western Undeformed Zone and an Eastern Deformed Zone. The former is composed of the gently east-dipping shelf sequence of upper Cambrian to lower Ordovician clastics and carbonates which unconformably overlie the Precambrian basement. The latter is characterized by lower to middle Ordovician carbonates, striking roughly north-south and dipping predominantly to the east, which are overlain by well-cleaved shales and slates. The stratigraphic …

The Champlain Thrust System In Northwestern Vermont - Structure And Lithology Of The Taconic Foreland Sequence In The Highgate Center Quadrangle, Michael Roger Haschke

Geology Theses and Dissertations

The Champlain Thrust System, responsible for the final emplacement of the Taconic Allochthon, and which represents the surface trace of the main detachment under the Taconic suite, can be traced throughout the study area in northwestern Vermont, northward into southern Quebec. In the Highgate and St. Albans area this imbricated assemblage consists of 3 main carbonate thrust slices (Highgate Springs-, Philipsburg-, Rosenberg slice), each of which contain rocks deposited during some part of early Cambrian to medial Ordovician time. The Highgate Springs sequence comprises a mildly deformed early to medial Ordovician carbonate-shale succession. Late Cambrian to early Ordovician carbonates of …

The Origin And Evolution Of The Southern Snake Range Decollement, East Central Nevada, Allen J. Mcgrew

Department of Earth, Environment and Sustainability Faculty Publications

Regional and local stratigraphic, metamorphic, and structural constraints permit reconstruction of the southern Snake Range extensional deformational system in east central Nevada. The dominant structure of the range, the southern Snake Range décollement (SSRD), operated during Oligocene and Miocene extensional deformation to exhume a footwall of multiply deformed metasedimentary and plutonic rocks. Intrusion of three plutons (∼160 Ma, 79.1 ± 0.5 Ma, and 36 ± 1 Ma, respectively) and development of two cleavages preceded the onset of extensional deformation. Plastic deformation of lower plate metasedimentary rocks accompanied the early phases of regional extension and produced bedding-parallel grain shape foliations and …

A Paleoseismic Investigation Of The Mcgregor Fault, East-Central New York, Steven J. Tice

Geology Theses and Dissertations

The structural disposition and movement potential of the McGregor Fault System in Eastern New York State are reviewed from the perspective of a paleoseismic investigation. The McGregor Fault zone has been located beneath deltaic sediments west of West Glens Falls using commercial and residential bore hole data and microgravity surveys. A 34 m long trench was excavated in overburden near the western margin of the McGregor Fault zone to a depth of 3.2 m. Stratified fluvially deposited sediments were exposed which showed no evidence of earthquake induced deformation or offset. However, the overburden present here does not possess optimal qualities …

Regional Tectonic Deformation Of The Northern Oregon Coast As Recorded By Pleistocene Marine Terraces, Richard Alan Mulder

Dissertations and Theses

Pleistocene marine terraces of the northern Oregon coast are an important factor in understanding the tectonics and paleoseismicity of the central Cascadia subduction zone. The lowest marine terrace, tentatively correlated to 80,000 year old Whiskey Run terrace of southern Oregon, is intermittently exposed in the present day sea cliff along an 80 km section of coastline between Tillamook Head and Cape Kiwanda. Terrace sediments consist largely of fine material such as clay, silt and fine sand with several locations containing large amounts of gravel derived from nearby headlands and steep bedrock hills. The terrace sediments are interpreted to be deposited …

Slickenside Petrography: Slip-Sense Indicators And Classification, Young-Joon Lee

Geology Theses and Dissertations

Petrographic study has been carried out on slickenside thin sections, to find out reliable microstructures for determining the slip-sense of faults, and to classify slickensides morphologically. Thin sections are made cut parallel to the striation and perpendicular to the slip plane. Many useful slip-sense indicators are found in thin section even though such indicators may be absent in hand specimens. They are (1) off-set or bending of once-continuous bodies such as veins, layers, grains or twin lamellae, (2) crystal fibers growing nearly parallel to the slip direction, (3) extensional fractures aligned oblique to the slip plane, (4) S-C geometries in …

Significant Bedrock Features Of The Maine Coast : Boothbay To Calais, Carol White, A. M. Hussey Ii

Maine Collection

Significant Bedrock Features of the Maine Coast : Boothbay to Calais

Carol White and A.M.Hussey II

Planning Report # 85

A Report Prepared for the Maine Critical Areas Program, Maine State Planning Office, 184 State Street, Augusta, Maine 04333 (September 1989).

Contents: Introduction / Types of Significant Features / Description and Interpretation of Geologic Features / Overview of the Geology of Coastal Maine / Criteria for Significant Geological Localities / Inventory Methods / Area Descriptions / Site Descriptions / Conclusions and Recommendations / References

Ua66/8/2 Earthquake Risk Assessment For Warren County, Kentucky, Wku Center For Local Government, Nicholas Crawford, Thomas Tweddell, Shaun Winter, Peter Erlenbach, Amy Huot, Grant Whittle

WKU Administration Documents

Earthquake risk assessment report for Bowling Green and Warren County, Kentucky. Include illustrations and maps.

Contributions To The Quaternary Geology Of Northern Maine And Adjacent Canada, J. Steven Kite (Ed.), Thomas V. Lowell (Ed.), Woodrow B. Thompson (Ed.)

Maine Collection

Contributions to the Quaternary Geology of Northern Maine and Adjacent Canada

Bulletin 37 - Maine Geological Survey, Department of Conservation,

Augusta, Maine 04333 (1988).

Contents: Introduction / A GEOMORPHIC METHOD FOR RECONSTRUCTING PALEO ICE SHEETS, Part I: GLACIAL GEOLOGY. - T. Hughes and J. Fastook / A GEOMORPHIC METHOD FOR RECONSTRUCTING PALEO ICE SHEETS, Part II: GLACIOLOGY. - J. Fastook and T. Hughes / TILL STRATIGRAPHY AT THE BALD MOUNTAIN MINE SITE, NORTHERN MAINE - W. R. Holland and F. F. Bragdon / GLACIAL DISPERSAL FROM THE PRIESTLY LAKE AND DEBOULLIE PLUTONS, NORTHERN MAINE - E. F. Halter / GLACIATION …

Structural Geology Of The Northern Galice Formation, Western Klamath Mountains, Oregon And California, F. Ross Jones

Geology Theses and Dissertations

The Galice Formation is a thick, turbiditic flysch sequence that depositionally overlies the Josephine ophiolite in the western Klamath Mountains of northwestern California and southwestern Oregon. The Josephine ophiolite and Galice have been interpreted as the basement and sedimentary cover of a Late Jurassic back-arc basin that opened proximal to the continental margin. During the Nevadan orogeny (ca. 151-147 Ma), the ophiolite and overlying Galice sediments were thrust eastward beneath the continental margin along the regional Orleans fault. Two distinct Nevadan deformational phases are recognized in the Galice – an initial D1 or "main-phase" deformation and a later brittle deformation …

Geology, Geochemistry, And Geochronology Of The Lems Ridge Olistostrome, Klamath Mountains, California, Matthias Ohr

Geology Theses and Dissertations

The Lems Ridge olistostrome (LRO), located within the western Jurassic belt of the Klamath Mountains geologic province, is a melange unit showing a distinct block-in-matrix fabric. The conformable relationship to both an igneous basement and the overlying flysch of the Late Jurassic Galice Formation points to a sedimentary origin. The lack of pervasive deformation and the internal stratification also support a predominantly olistostromal origin of the LRO. The matrix of the LRO consists of pebbly mudstone which interfingers with tuffaceous greenstone and tuff-breccias. Subordinate beds of chert, argillite, and sandstone are also present. The matrix contains abundant ophiolitic clasts, fragments …

Dolomitization Of The Hatch Hill Arenites And The Burden Iron Ore, Peter Michael Hofmann

Geology Theses and Dissertations

The Taconic allochthon is a sequence of Cambrian or Precambrian to Ordovician rocks. It is composed of predominantly deep water argillaceous and subordinate arenaceous and calcareous rocks that were deposited on the continental rise and slope. During the Ordovician, sediments which were earlier deposited in the slope-rise environment were incorporated into the accretionary prism of an island arc that approached from the east, and subsequently overthrust the carbonate platform.
The Hatch Hill Formation is part of the Taconic sequence. It consists of dominantly black-gray slates, minor amounts of sandstones and carbonates. Previous workers have recognized the presence of dolomite and …

Chatham Fault Zone, Old Chatham-East Chatham, New York: Mesostructures And Microstructures: Their Spatial And Age Relationships, Jorge Mora M.

Geology Theses and Dissertations

Detailed studies in rocks of Mettawee (Late Precambrian? to Early Cambrian) and Walloomsac (Middle Ordovician) slates between Old Chatham and East Chatham, New York, have shown that these rocks were intensely deformed during the Taconic orogeny and a later deformation event(?). Two generations of structures are clearly recognized in the area. The first generation (G1) includes tight west-verging folds whose axial plane foliation is the regional foliation slaty cleavage (S1). These structures are considered synchronous with the regional metamorphism of the Taconic orogeny and correlative with those structures belonging to the D2 deformation event proposed by Ratcliffe (1979) and Rowley …

Stratigraphy And Structure Of The Miocene "Esmeralda" Formation In Stewart Valley, Mineral County, Nevada, Benjamin L. Clausen

Loma Linda University Electronic Theses, Dissertations & Projects

The Miocene rocks of Stewart Valley, eastern Mineral County, Nevada, consist of volcanic flows and breccias and fluvio-lacustrine sedimentary rocks. They are called the Esmeralda Formation because they contain lithologies similar to those of the Esmeralda type section 100km south; however, the rocks in Stewart Valley were probably deposited in a separate local basin. The lower part of this formation contains small lacustrine claystone deposits (unit 1) that interfinger with volcanic breccias and flows (unit 2). The main fluvio-lacustrine sequence is above the flows and·is divided by the author into five units based on lithology: sandstone and claystone in unit …

Structure And Tectonics Of The Keban Metamorphics In The Northern Margin Of The Bitlis Suture Zone, Southeastern Turkey, Gültekin Savci

Geology Theses and Dissertations

The study area near Keban consists of the allochthonous Keban division of the Keban-Malatya crystalline complex and the Yuksekova island-arc rocks of the Bitlis-Puturge Complex in the northern margin of the Bitlis Suture Zone. Detailed mapping shows that the Palaeozoic-Triassic Keban Metamorphics are composed of the following formations: (1) white, massive, karstic Kirklar Marble; (2) phyllitic psammite with calcschist interlayers Calik Formation; and (3) semi-crystallized gray Koyunatlayan Limestone. These formations define a tectonostratigraphy with the Kirklar Marble at the base and the Koyunatlayan Limestone at the top. The detailed lithological description of the Keban Metamorphic rock assemblages suggest that they …

The Pre-Tertiary Geology And Mesozoic Tectonic Evolution Of Eastern China, Southeast Asia And Adjacent Regions, Michael P. Klimetz

Geology Theses and Dissertations

Several orogenic belts transecting south-eastern Asia are the sites of former convergent plate margins although there have been varying interpretations of the collisional framework of individual continental blocks, styles of convergence at these zones and the timing of respective collisions. A comprehensive tectonic study of eastern China, Mongolia and the southern Soviet Far East indicates the collision of the South China Block with a combined North China-Northeast China Fold Zone Block in the late Triassic-early Jurassic, their collective suturing to Eurasia in the late Jurassic-early Cretaceous, followed by the Sikhote Alin-Japan Block in the mid to late Cretaceous. The evidence …

Structure And Stratigraphy Of West Haven, Vermont, Christoph K. Steinhardt

Geology Theses and Dissertations

Mapping and structural investigations in an area bounded to to the west by by Grenvillian basement and to the east by allochthonous rocks emplaced during the medial Ordovician Taconic Orogeny led to division of the area into a Western Undeformed Zone and an Eastern Deformed Zone. The former consists of a thin, undeformed shelf sequence of upper Cambrian to lower Ordovician (Canadian) clastics and carbonates, which unconformably overlie Grenvillian basement and dip gently to the east.
The Eastern Deformed Zone consists of early to medial Ordovician carbonates folded about northnortheast trending axes with east to southeast dipping axial surfaces, overlain …

Geological And Thermal Aspects Of The Southern San Joaquin Basin, California: Application Of The 40ar/39ar Stepwise Heating Technique To Detrital Microclines, Kenneth Bé

Geology Theses and Dissertations

The depositional history of the southernmost region of the trough-shaped San Joaquin Basin spans from Upper Eocene to Recent time. The stratigraphy reveals both a predominantly marine environment which persisted until the Upper Pliocene, as well as nonmarine environments along the basin's margins. Folds and faults within the basin have resulted directly from movements along the San Andreas fault. Although the exact time of origin of the Big Bend is unclear, this major feature in the San Andreas fault's geometry has played an important role in recent crustal tectonics of southern California. Significantly, the southern San Joaquin's depocenter has undergone …

Lithologic And Structural Controls On Karst Landforms Of The Mitchell Plain, Indiana, And Pennyroyal Plateau, Kentucky, Frederick Jennings Woodson

All-Inclusive List of Electronic Theses and Dissertations

Karst features in Harrison County, Indiana, and the Mammoth Cave region, Kentucky, are profoundly influenced by lithology and structure. In the Sinkhole Plain two classes of sinkholes, shallow solutional and deeper subsidence, differ in morphology, origin, age, distribution, and density. Distributions of the two kinds of sinkholes reflect the outcrop pattern of specific lithostratigraphic units. Broad shallow dolines (Ste. Genevieve-type sinks) develop on the Horse Cave Member of the St. Louis Limestone and on the Ste. Genevieve, Girkin, and Paoli Limestones. Innumerable steeper-sided subsidence and collapse depressions (St. Louis-type sinkholes) form on the Corydon Chert Member, lower St. Louis Limestone, …

Geology Of The Plutonic And Hypabyssal Rocks Of The Betts Cove Ophiolite Complex, Newfoundland, Bruce D. Idleman

Geology Theses and Dissertations

The Betts Cove ophiolite complex lies within the Dunnage Zone island arc terrain of central Newfoundland. It forms the base of the lower Ordovician Snooks Arm Group, which consists of mafic igneous rocks of the ophiolite and a thick sequence of volcanic and volcaniclastic rocks which conformably overlies it. The Snooks Arm Group is unconformably overlain by sub-aerial sediments and volcanics of the presumed Silurian Cape St. John Group.
The base o£ the ophiolite complex consists predominantly of ultramafic rocks. These are interlayered on a variety of scales, and show mesoscopic igneous structures which suggest that they were produced by …

Structural Studies Of The Ordovician Flysch And Melange In Albany County, New York, Frederick W. Vollmer

Geology Theses and Dissertations

The middle Ordovician rocks of the Albany 15 minute quadrangle comprise interbedded graywacke and shale, and in the east, coarse cobble or olistostromic deposits. The detrital composition, westward fining and regional westward transgression of these deposits indicate that these were sediments shed off the westward thrusting Taconic Allochthon. Primary sedimentary structures show that these rocks were deposited by turbidity currents flowing into a longitudinal trough, probably formed in response to increased load during overthrusting. Although strongly dependent on lithology, deformation intensity generally increases from west to east; from essentially undeformed bedded flysch through asymmetrically folded and thrust beds to highly …