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Stratigraphy
Published in Dexter Perkins, Kevin R. Henke, Adam C. Simon, Lance D. Yarbrough, Earth Materials, 2019
Dexter Perkins, Kevin R. Henke, Adam C. Simon, Lance D. Yarbrough
Geologists investigate rock lithologies and stratigraphy using several approaches. The main kinds of stratigraphy fall into three areas: lithostratigraphy, biostratigraphy, and chronostratigraphy. Lithostratigraphy involves identification and classification of strata based on their lithologic (physical) characteristics. Biostratigraphy involves identifying and correlating rocks of similar ages based on the fossils they contain. Chronostratigraphy— closely related to biostratigraphy—involves rock age too, but the goal is to assign absolute ages to lithographic units. Thus, biostratigraphers may determine that one formation is older than another, and chronostratigraphers may be more concerned with how many million years ago a particular formation formed. Other kinds of stratigraphy, all closely related to the three main kinds, include chemostratigraphy (study of the variation in rock chemistry), cyclostratigraphy (study of variations in sedimentary rocks due to long-term climate cycles), magnetostratigraphy (study of variations in the magnetic fields recorded by rocks), and archaeological stratigraphy (study of the stratigraphy associated with archaeological studies).
Devonian-Carboniferous Boundary in the Neritic Facies Areas of South China from the Viewpoint of Integrative Stratigraphy
Published in Wang Naiwen, J. Remane, Stratigraphy, 2020
Wang Xunlian, Zhang Shihong, Xue Xiaofeng
Integrative stratigraphy attempts to make full use of stratigraphic data, including physical, chemical and biological, and specially emphasizes combined study by using all stratigraphical methods. In addition to biostratigraphy, lithostratigraphy, and chronostratigraphy, other methods, including event stratigraphy, sequence stratigraphy, ecostratigraphy, stable isotope stratigraphy, seismic stratigraphy, and magnetostratigraphy, have been employed more and more with success in practice. All these methods are complementary and could be tested and verified with each other, thus providing an effective tool for precise correlation.
Salt Insertions in Sedimentary Sequences: Impacts on Sediment Distortion and Sediment Fracturing
Published in Ian Lerche Ph.D., Kenneth Petersen, Salt and Sediment Dynamics, 2017
Figure 3.17 shows the stratigraphic occurrence of six negative δ13C events (Events 1–6) in two exploration wells (E and F) located approximately 15 mi apart in the Green Canyon Block, offshore Louisiana (Figure 3.18). Events 1–6 have been correlated between the wells, and age assignments for the events made by integrating high resolution isotope chronostratigraphy and calcareous nannofossil biostratigraphy (Wilhams and Trainor, 1987; Wilhams et al, 1988). Events 1–6 range in age from 1.3–1.8 Ma and are correlative between wells E and F within ±30,000 years.
Volcanoes buried in Te Riu-a-Māui/Zealandia sedimentary basins
Published in New Zealand Journal of Geology and Geophysics, 2020
Alan Bischoff, Andrea Barrier, Mac Beggs, Andrew Nicol, Jim Cole, Tusar Sahoo
The age of the volcanic rocks in the subsurface is rarely determined by radiometric dating and is primarily achieved by mapping chronostratigraphic surfaces that correlate seismic anomalies possibly of igneous origin with biostratigraphic markers identified in the drillholes. Chronostratigraphic mapping follows seismic and sequence stratigraphic principles such as stratal reflection relationships and depositional trends within seismic facies (e.g. Mitchum and Vail 1977; Hunt and Tucker 1992; Catuneanu 2006), giving time resolution in the order of few (<5 Myr), similar to the precision of radiometric ages. Interpretation of the environment in which the eruptions occurred was determined by plotting the location of volcanoes on paleogeographic maps of similar age (Arnot et al. 2016), and/or by calibration with paleoenvironmental data obtained from microfossils from drillholes across the studied areas.
High-resolution event stratigraphy (HiRES) of the Silurian across the Cincinnati Arch (USA) through integrating conodont and carbon isotope biochemostratigraphy, with gamma-ray and sequence stratigraphy
Published in GFF, 2020
Stephan C. Oborny, Bradley D. Cramer, Carlton E. Brett
Silurian strata of the Cincinnati Arch region of southern Ohio, eastern Indiana, and northern Kentucky have undergone extensive litho- and biostratigraphic analyses for well over a century (Orton 1871; Foerste 1896, 1897, 1905, 1906, 1917, 1929, 1935; Bowman 1956; Kauffman 1964; Rexroad et al. 1965; Horvath 1969; Berry & Boucot 1970; Droste & Shaver 1976, 1980, 1982; Flanagan 1986; Kleffner 1987, 1990, 1994). Though these studies were seminal in the correlation of strata throughout the region, precise chronostratigraphic relationships were frequently inhibited by rapid changes in facies, pervasive dolomitization, and an overall paucity of diagnostic faunas. As a result, several longstanding regional stratigraphic issues arose and a complicated and convoluted nomenclatural hierarchy was established for units throughout the tristate area. Recent litho-, sequence-, and biochemostratigraphic analyses of Rhuddanian through middle Sheinwoodian strata traversing the Cincinnati Arch resolved a number of these stratigraphic issues (Brett & Ray 2005; McLaughlin et al. 2008; Cramer 2009; Brett et al. 2012; McLaughlin et al. 2012; Sullivan et al. 2016; Waid 2018). However, points of disagreement remain between the sequence stratigraphic and biochemostratigraphic correlations of overlying Sheinwoodian through Homerian strata. Part of the challenge is that a nomenclatural divide exists across the Cincinnati Arch between the Appalachian and Illinois basins and our ability to fully ascertain the chronostratigraphic relationships of strata for this interval remains problematic.
An extended GIS-based Dempster–Shafer theory for play-based hydrocarbon exploration risk analysis under spatial uncertainty conditions, case study: Zagros sedimentary basin, Iran
Published in Georisk: Assessment and Management of Risk for Engineered Systems and Geohazards, 2019
Sahand Seraj, Mahmoud Reza Delavar
The chronostratigraphic chart of Fars domain (Figure 3) shows the age of the rocks strata of the study area in relation to time. The ultimate aim of chronostratigraphy is to arrange the sequence of deposition and the time of deposition of all the rocks within a geological region, and eventually, the entire geologic record of the Earth. It has five units which are the eonothem, erathem, system, series and stage. The Paleozoic is an erathem lasting from 541 to 251.902 million years ago, and is subdivided into six geologic periods (from the oldest to the youngest): the Cambrian, Ordovician, Silurian, Devonian, Carboniferous, and Permian. The Permian system in Fars area is coincidence with the Dehram group. Each group has several layers that are nominated as formations. The Dehram group has five formations which are depicted in Figure 3.