The structure of the naturally occurring, iron-rich mineral Ca1.08(6)Mg0.24(2)Fe0.64(4)Mn0.04(1)(CO3)2 ankerite was studied in a joint experimental and computational study.
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— The matrix is the mud: physically deposited material that consists mostly of clay minerals and quartz. Cement is the chemically precipitated filling of original void spaces. Some sandstones lack any matrix; only mineral cement occupies the spaces among the framework particles.
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— The Upper Triassic Yanchang Formation is a major tight oil sandstone reservoir in the Ordos Basin with a thickness of approximately 1000–1300 m (Yang et al., 2015).From top to bottom, the Yanchang Formation was divided into 10 oil-bearing members: Chang 1–Chang 10 (Fig. 1 B).Chang 7 is the most important oil-generating …
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— Sandstone is typically a well-cemented rock, meaning that the sand grains are held together by some type of mineral cement, such as silica, calcium carbonate, or iron oxide. The degree of cementation can …
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tivity, allowing focus on the iron oxide mineral cement and evaluation of the parameters affecting the cementation pro-cess. Concretion cement can be hematite or goethite, and sometimes both. Large concretions (>5 cm diameter) commonly exhibit internal patterns including rinds, multiple layers, and bul-bous growth toward the interior (Fig. 1F).
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— The dolomite cement with a mosaic texture commonly fills intergranular pores of the sandstone (Fig. 7a, b), or occurs at the edge of clastic particles in the sandstone (Fig. 7c, d). Dolomite cement has a zigzag shape in all cases (Fig. 7c, d), and it shows orange-red cathodoluminescence and a zonal texture (Fig. 7e, f). The
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— Sandstone. Any sedimentary rock composed of stony grains between 1/16 mm and 2 mm in diameter that are cemented together is a sandstone.. Sandstone forms from beds of sand laid down under the sea or in low-lying areas on the continents. As a bed of sand subsides into the earth's crust, usually pressed down by over-lying sediments, it …
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The three, most common, chemical cements in sedimentary rocks such as sandstone are silica (quartz), calcium carbonate (calcite), and the iron oxides. -Calcite-cemented sandstones are typically light colored, react w acidic -Quartz-cemented sandstones are also light colored, but they do not visibly react with acids and the cementing material is ...
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— Clay minerals are one of the most important groups of minerals that destroy permeability in sandstones. However, they also react with drilling and completion fluids and induce fines migration during hydrocarbon production. They are a very complex family of minerals that are routinely intergrown with each other, contain a wide range of solid …
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— Diagenetic iron (oxyhydr)oxide minerals are common precipitates expected in CO2 reservoirs, and these minerals record fluid flow for application to carbon capture and sequestration (CSS). Multiple mineralogy and spectroscopy analyses on a pore to meter scale characterize a well-exposed, lithologically controlled, iron (oxyhydr)oxides reaction …
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— Box-like and spherical concretion rinds typically enclose a core of bleached, more friable sandstone. There is evidence of fracture control of the box-like concretions: …
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— Different contents of Fe-bearing minerals, including biotite, Fe-Ti oxides, pyrite, hematite, goethite, and chlorite that were formed or altered under different redox conditions, resulted in sandstone units with distinct colors. The red sandstone is hematite-rich, indicating a highly oxidizing environment.
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The term siliciclastic refers to sediments composed mostly of silicate minerals. The most common sedimentary rocks – including shale, sandstone, and conglomerate – form from siliciclastic sediments. Other …
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— Cements are post-depositional diagenetic products that fill voids between framework and matrix grains. Cementation can begin soon after deposition (commonly …
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— Note the replacement of early calcite cement by hematite in the Red Unit; (c) abundant iron cement (mainly hematite and goethite) impacts a floating grain texture in part of the Wajid Sandstone ...
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— Iron oxide cements have δ 56 Fe values that are typically negative and as low as −0.74‰. In contrast, iron oxide-stained Navajo Sandstone in close proximity to a rinded iron oxide concretion has δ 56 Fe values that are 0.9 to 1‰ greater than the δ 56 Fe value of the associated iron oxide concretion
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— Adding oil to a sandstone stops clay diagenesis if the sandstone is oil-wet but probably only slows clay reactions if the sandstone is water-wet. Sandstones tend to be more oil-wet as the Fe-bearing clay content of the sand increases and as oil becomes more enriched in polar compounds.
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Keywords: Sandstone; Siliceous cement; Carbonate cement; Ferruginous cement; Paleohydraulics; Geomorphology; Sandstone landforms Introduction Mineral cement is the most important intrinsic factor in estimating erosion rates in sandstone regions. Its composition is a function of mineral availability in the basin and burial/thermal history of …
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— Iron isotope compositions of oxide concretions in the Navajo Sandstone document reductive dissolution of early diagenetic oxides, aqueous transport, and finally …
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— We measured δ 56 Fe values of iron-bearing minerals from whole-rock Navajo Sandstone, concretionary iron oxide cements, iron oxide stains that are oriented in the direction of paleo-groundwater flow, iron oxide stains on the interior of rinded concretions, and ferroan carbonate cements. We have then combined these data with …
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— Sandstones of rift basins (arkoses) and collision-margin basins (litharenites) generally have only a few percent quartz cement; quartzarenites and other quartzose sandstones of intracratonic, foreland and passive-margin basins have the most quartz cement. Clay and other mineral coatings on detrital quartz grains and entrapment of …
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— The objectives of the paper are, for sandstones, to 1) summarise the main detrital grain types, 2) summarise the main diagenetic mineral cements, 3) summarise the main pore-types, 4) provide illustrative SEM-EDS images of sandstone end-member types, cements and pore-types, 5) detail the main processes that alter the key sandstone …
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— The formation of hematite and goethite concretions in different sedimentary rocks including sandstones is an important diagenetic process in the geologic history of the Earth. Its interpretation can also contribute to understanding the diagenetic history of Martian iron hydroxide concretions.A case study of iron-rich concretions from Estonian …
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Iron oxide (e.g. hematite, goethite) sandstone coloration and concretions are significant indicators of the mobility of iron in groundwater and host rock properties such as por …
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— The carbonate cements in tight sandstone reservoirs are diverse, complex, and important determinants of reservoir quality. This study provides a comprehensive analysis of the characteristics and formation mechanism of carbonate cement in the tight sandstone reservoirs of the Xu3 Member within the Xujiahe Formation in the depression …
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— Generally, iron oxide minerals occurred in the Paleozoic sequences as pore-filling cement with various sandstone types and are associated with clay minerals and occasionally with calcite cement.
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DOI: 10.1016/j.jseaes.2022.105099 Corpus ID: 245900191; Effect of authigenic clay minerals and carbonate cements on quality of tight sandstone reservoirs: insight from Triassic tight sandstones in the Huaqing area, Ordos Basin, Northern China
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— The main contents of this paper are as follows: (1) clarify the development characteristics and diagenetic evolution sequence of authigenic clay minerals and carbonate cements in the Ch6 3 tight sandstone; (2) characterize the pore and throat structure and clarify the main reason for the widespread development of micropore …
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cylindrical rinds of iron oxide that cement grain-supported sandstone, and iron oxide ce-ments fill the void space within some thick, tabular masses of channel sandstone. Thin …
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The most common mineral grains in sandstone are quartz, feldspar, and lithic fragments. Cement: The cement of a sandstone is the material that binds the sand grains together. The most common cements are silica, …
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