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Knowledge-Based Module for Site Characterisation
Published in Nebojša Kukurić, Development of a Decision Support System for Groundwater Pollution Assessment, 2020
Rock types are described, especially with respect to their hydrogeological characteristics. This topic is also meant to be a reminder on basic classification and characteristics of rocks. Although at a first glimpse superfluous, the Topic is important, especially for the users with a nongeological background. Knowledge on rocks origin, genesis and composition is crucial for understanding aquifer evolution and nature. The nature and distribution of groundwater systems are controlled by lithology, stratigraphy (sedimentary rocks) and structure of the geological deposits. For the sedimentary unconsolidated rocks and soil, texture is an important parameter for lithological characterisation. Colour can be used as indicator of similarities or differences among the lithological units. Deposits of the sedimentary rocks of different age and lithology form so-called lithostratigraphic units. If the GWS contains lithostratigraphic units, their spatialdistribution has to be determined.6 Finally, various structures that occur in soil and rocks could substantially influence the spatial distribution of GWS units, as well as groundwater flow and contaminant transport within the system.
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).
Stratigraphy and Sedimentation
Published in Supriya Sengupta, Introduction to Sedimentology, 2017
The ‘material units’ and the ‘temporal and chronostratigraphic units’ of Table 8.2 correspond respectively to the observable and inferential units of the conventional scheme. Of the material units, again the lithostratigraphic units are used for categorising and ranking of deposits of sediments in the field. The fundamental lithostratigraphic unit, called a formation, is defined as ‘a body of rock identified by lithic characteristics and stratigraphic position; it is prevailingly, but not necessarily tabular and is mappable at the earth’s surface or traceable in the subsurface.’
Middle Jurassic–Lower Cretaceous stratigraphy of the northern Great Australian Superbasin: insights from maximum depositional age constraints from the U–Pb detrital zircon record
Published in Australian Journal of Earth Sciences, 2022
E. K. Foley, E. M. Roberts, R. A. Henderson, C. N. Todd, E. M. Knutsen, C. Spandler
Knowledge of how stratigraphic units correlate in time and space is integral to basin studies. Robust chronostratigraphic controls greatly assist in deciphering geological histories from basinal records. Examples of this include the precise age assignment of paleontological discoveries (e.g. Kowal-Linka et al., 2019; Langer et al., 2018), improved appreciation of the configuration of aquifer (e.g. Smith et al., 2017) and hydrocarbon reservoir units (e.g. Lewis & Sircombe, 2013; Yang et al., 2018), and clearer insight into the paleogeographic evolution of continents (e.g. Brennan et al., 2021; Foley, Henderson et al., 2021). Similarly, the correlation of stratigraphic units over large distances, such as across the succession related to the Cretaceous Western Interior Seaway of North America (e.g. Eldrett et al., 2015) or along the east Gondwana margin (Adams et al., 2011), is greatly advanced by chronostratigraphic control. This approach has proven more rigorous and less prone to potential error than correlation based on lithostratigraphy or even sequence stratigraphy, particularly when applied in a non-marine context, where biostratigraphic age control is limited (e.g. Wainman & McCabe, 2020).
Geoheritage importance of stratigraphic type sections, type localities and reference sites—review, discussion and protocols for geoconservation
Published in Australian Journal of Earth Sciences, 2019
M. Brocx, C. Brown, V. Semeniuk
Stratigraphy is the descriptive science of strata (Hedberg, 1976; Murphy & Salvador, 1999; Salvador, 1994), and within this, the disciplines of lithostratigraphy and volcanic stratigraphy provide a rich history of planet Earth in its layered sedimentary and volcanic development (Boggs, 1987; Cas & Wright, 1988). Biostratigraphy, the science that deals with distribution of fossils in the stratigraphic record and the organisation of strata into units on the basis of their fossil content (Hedberg, 1976), is included here because, first, paleontological components that define biostratigraphy reside in sedimentary sequences and, second, record the evolution of Life and the response of life forms to changing environments and climate. In recent years, Global Boundary Stratotype Section and Point (GSSP) has been established as an internationally agreed upon reference point on a stratigraphic section to define the lower boundary of a stage on the geological time-scale (Cohen, Finney, Gibbard, & Fan, 2013; Remane et al., 1996).
Paired δ13Ccarb and δ13Corg records of the Ordovician on the Yangtze platform, South China
Published in Australian Journal of Earth Sciences, 2018
B.-Y. Li, D.-W. Zhang, X.-Q. Pang, P. Gao, D.-Y. Zhu, K.-Z. Guo, T.-Y. Zheng
In the Qiliao section, the Lower Ordovician is conformable with the upper Cambrian Maotian Formation dolomites, and the Upper Ordovician is conformable with the lower Silurian Longmaxi Formation black shales (Figure 2). The total thickness of the Ordovician is 463.8 m. The Ordovician can be subdivided, from bottom to top, into the Nanjinguan, Fenxiang, Honghuayuan, Dawan, Shihtzupu, Pagoda, Linhsiang, and Wufeng formations. The Lower Ordovician includes the Nanjinguan, Fenxiang, Honghuayuan, and lower Dawan formations, the Middle Ordovician consists of the upper Dawan and Shihtzupu formations, and the Upper Ordovician covers Pagoda, Linhsiang, and Wufeng formations. The Qiliao section is paleogeographically located on the same carbonate platform as the widely studied Yichang area (Chen et al., 2000, Chen et al., 2006; Rong, Chen, & Harper, 2002; Yang et al., 1975; Zhan & Jin, 2007; Zhang et al., 2010), which can provide lithostratigraphy, biostratigraphy, and chronology data for improving the stratigraphic division and correlation. The eight formations at the Qiliao section, from oldest to youngest are: