China
Africa
Explore chapters and articles related to this topic
Urban Geologic Mapping
Published in Daniel T. Rogers, Urban Watersheds, 2020
Facies are the characteristics of a sedimentary rock mass that reflects its depositional environment. Facies analysis or cross-dating is a technique used to help understand sedimentary environments and the processes leading to the origin of their sediments (Anderton 1985). Facies analysis can be performed when two or more stratigraphic columns are developed for different locations within a given area. Facies analysis is conducted to: Evaluate the completeness of sedimentary deposits at any one locationIdentify any gaps in the depositional recordReconstruct the geologic history of a regionIdentify or confirm the historical occurrence of geological processes within a given regionReconstruct a succession of eventsCreate a vertical succession of depositional record
Minerals, rocks and sediments
Published in Richard J. Chorley, Stanley A. Schumm, David E. Sugden, Geomorphology, 2019
Richard J. Chorley, Stanley A. Schumm, David E. Sugden
A facies is a spatially distinguishable and limited part of a stratigraphic time unit, differing from other areal parts of the same unit in some physical and/or chemical (i.e. lithofacies) and/or organic (i.e. biofacies) sense. Time units are bodies of sedimentary rock, perhaps with areal variations in facies, laid down within a given time interval (Figure 4.16). Rock units are continuous bodies of uniform facies not necessarily all deposited within a given restricted time interval. A time-rock unit is a rock body of uniform facies laid down within a given time interval. Because of regular lateral changes in the loci of given types of sedimentation (e.g. migration of shorelines or river channels), sedimentary facies changes which are observed laterally are often found to form a vertical sequence through time (Figure 4.17). This principle is expressed as Walther’s Law which implies that each distinctive sedimentary environment possesses its own characteristic and ordered suite of facies, recognizable both spatially and in vertical section. In Figure 4.17 a regression of the sea has produced a prograding (forward-building) shoreline and an offlapping sedimentary sequence of which certain vertical sections mirror the character and order of the facies changes observed in the spatially disposed surface outcrops.
Sedimentary Rocks
Published in F.G.H. Blyth, M. H. de Freitas, A Geology for Engineers, 2017
F.G.H. Blyth, M. H. de Freitas
The succession of sediments illustrated in Fig. 6.5 records an orderly sequence of events in which shallow water deposits grade into deeper water sediments, succeeded by shallow water and continental deposits. In this example the shallow water sediments (conglomerates, gravels and coarse sands) can be grouped as an association of similar materials (i.e. a facies, p. 113). Other groupings can be made of the sediments accumulated in deeper water, deltas and on land. The facies to which a deposit belongs will indicate the other types of sediment with which it may be associated. For example, a foundation engineer building on alluvium may assume that this facies will contain gravel, sand and clay, and possibly conglomerate, and that care must therefore be taken to ascertain the presence of clay even though sand and gravel may be the only deposits visible at ground level.
Geochemical evaluation of hydrocarbon generating potential and thermal stress experienced by Patala Formation, Salt Range, Upper Indus Basin, Pakistan
Published in Petroleum Science and Technology, 2023
Arif Nazir, Abid Ali, Zahid Ali, Munawar Iqbal
Coal is considered better source of energy with worldwide distribution (Lechner et al., 2016). Pakistan has a vast amount of coal reserves and has a vital character in the country's development (Ahmad et al., 2015). Patala Formation (coal) is about 5 to 9 meters thick, dark gray shale, quartz sandstone, silt, marl and limestone carbonaceous shale while it is located on the eastern flanks, middle salt zone. The Patala Formation is present on the eastern flanks, middle salt zone and rises to the west in the limestone unit of Lockhart and Hangu formations. This formation has reasonable exposure in the Salt Range, Kala Chitta Range, Kohat and Hazara regions (Kadri, 1995). The organic matter content, sedimentary facies, and reservoir environment are useful in selecting formations to investigate hydrocarbons (Maravelis et al., 2015).
Characteristics of paleoenvironmental changes from Badaowan formation to Sangonghe formation in Tuziakne Ditch, northwest margin of Junggar Basin, China
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2021
Chong Feng, Guoxiang Wang, Hua Cai, Teng Li, Yinlan Nie, Muchuan Yang, Shuaikang Zhou, Tong Wu
The sedimentary structure and grain size characteristics can further reflect the types of sedimentary facies. 1) Braided river (arid braided river): huge gravels (Figure 8a), fuzzy imbricated sedimentary structure (Figure 8b) and cross bedding composed of gravels (Figure 8c), which are typical characteristics of braided river channel sedimentation. On the section, the conglomerate lens (Figure 8g) were also found with opposite lamination tendency, which is a typical sedimentary feature of braided river central beach. Grain size analysis of S7 and S8 samples shows that they have river sedimentary features during flood period (Type 3 and Type 4 in Figure 6). 2) Stable channel braided river (wet braided river): large sandstone lens with convex bottom and flat top (Figure 8d), channel cross bedding sand formed by unidirectional circulation (Figure 8e), climbing ripple cross bedding formed under stable embankment environment (Figure 8h), and flood plain fine-grained sediments in the upper part of the “binary structure” of a complete river (Figure 8f); according to the characteristics of cumulative probability curve of grain size, Samples S1, S3, S4, S5, S6 and S11 are sandstones (Type 1 of Figure 6) deposited in the environment of stable channel braided river (wet braided river). 3) Lake: thick horizontal bedding mudstones with obvious characteristics (Figure 8i). 4) Underwater distributary channel of delta front: thin sand body composed of siltstones and fine sandstones, with well sorted and fine-grained grain size characteristics (Type 2 in Figure 6).
Evidence for non-marine Jurassic to earliest Cretaceous sediments in the pre-breakup section of the Mentelle Basin, southwestern Australia
Published in Australian Journal of Earth Sciences, 2020
C. C. Wainman, I. Borissova, D. L. Harry, R. W. Hobbs, D. J. Mantle, A. Maritati, E. Y. Lee
A measured section was compiled using sedimentological data and high-resolution photographs collected on core from ∼334.70 through to 512.98 mbsf (Figure 5). Macroscopic characteristics including bedding thickness, lithology, clast population, colour, sedimentary structures, diagenetic constituents, bioturbation intensity, bedding contacts, and macrofossil types were obtained from shipboard observations. Where appropriate, microscopic characteristics from smear slides and thin-sections obtained from set intervals were incorporated into the measured section. The limited recovery of core prevented determination of true bedding thickness. Measured sections were divided into facies based on grainsize and sedimentary structures that reflect depositional processes. Facies found in close association with one another were grouped into facies associations, and their depositional environments were then interpreted.