Clastic grains exhibit approximately lognormal size distributions in most sedimentary rocks. These lognormal distributions are essentially random ones and reflect the fact that most processes of erosion, transportation, and deposition affect only the medians and sorting coefficients, but not the ...
[1] Grain-size analyses of the soils at Meridiani Planum have been used to identify rock sources for the grains and provide information about depositional processes under past and current conditions. Basaltic sand, dust, millimeter-size hematite-rich spherules interpreted as concretions, spherule fragm...
Summary values of local grain size (e.g., D84 or D50, the size at which 84% or 50% of measured b-axes are finer) have been estimated from photographs (so-called ‘photosieving’ methods) using semivariograms of image texture (e.g., Carbonneau et al., 2004, Verdú et al., 2005)...
Sign in to download full-size image Figure 12.27.Thin-section photomicrographs illustrating major reservoir porosity types found in Upper Jurassic reservoirs in the central Gulf Coast. (A) Primary intergranular porosity (8%) in sequence UJ III, Walker Creek Field, Columbia County, Arkansas. Ooids ...
Full size image The clastic nature of the most recent sediments in the area, i.e., the Quaternary and the Miocene sequences, enables the characterization of the clastic depositional systems using the GSD. Moreover, the study area ensures good spatial data coverage, with over 20,000 lithology...
Table 1 Characteristics of grain-size frequency curves of the main wells in the study area 566 地 球 学 报 第三十一卷 斌等, 2003)。从上面的分析来看, 研究区砂体成因较 复杂, 各井砂体粗、细粒混合, 且粗、细沉积物的含 量也存在差异。因此需首先判定这种混合沉积物 沉积时的具体水动力环境...
The link between grain-size components and depositional processes in a modern clastic lake. Sedimentology 59: 1050-1062.Xiao J L, Chang Z G, Fan J W, Zhou L, Zhai D Y, Wen R L, Qin X G (2012). The link between grain-size components and depositional processes in a modern clastic ...
GRAIN sizeHEAVY metalsENVIRONMENTAL degradationENVIRONMENTAL riskEOCENE EpochCLASTIC rocksANALYTICAL geochemistryANTHROPOGENIC effects on natureThis study describes the role of grain size in controlling the pollution levels in clastic sedimentary rocks, by presenting results from the Eocene sequence in NE T眉...
(G) Compressed and cataclastically deformed, showing intense grain-size reduction. Microfractures suggest that grain size reduction is related to grain crushing, but there is also textural evidence for pressure solution.(A) Figure 4a from Karner, S.L., Chester, F.M., Kronenberg, A.K., ...
Francus P. An image-analysis technique to measure grain-size variation in thin sections of soft clastic sediments[J]. Sedimentary Geology, 1998, 121: 289- 298.Francus, P., 1998. An image-analysis technique to measure grain- size variation in thin sections of soft clastic sediments. ...