Ankerite

About: Ankerite is a research topic. Over the lifetime, 859 publications have been published within this topic receiving 23960 citations.

Mineralogical Characteristics of Early Permian Paragonite-Bearing Coal (No. 3) in the Jinyuan Mine, Tengxian Coalfield, Shandong Province, Eastern China

Abstract: The Early Permian coal is of great value in the Tengxian Coalfield, Shandon Province, Eastern China. This work deals with the new data focusing on mineralogical characteristics in the Early Permian Shanxi Formation No. 3 coal from the Jinyuan Mine. The Jinyuan coal is a low ash and highly volatile A bituminous coal. Minerals in the No. 3 coal mainly comprise of kaolinite, ankerite, illite, calcite, siderite, and quartz, with varying compositions of trace amounts of pyrite, jarosite, bassanite, anatase, and rutile. According to mineral assemblage in the coal plies, three Types (A to C) can be identified in the No. 3 coal. The dominant minerals in Type A are poorly-ordered kaolinite, illite, quartz, pyrite, and jarosite. Type B is mainly composed of well-ordered kaolinite, illite, siderite, ankerite, and calcite. Type C, with just one sample (JY-3-7c), which contains high proportions of calcite (54%) and ankerite (34%). Terrigenous minerals are elevated in coal plies that typically have relatively high contents of ash yield. The formation of syngenetic pyrite was generally due to seawater, while the sulphate minerals (jarosite and coquimbite) were derived from the oxidation of pyrite. Epigenetic vein-like or fracture-fillings carbonate minerals (ankerite, calcite, and siderite), kaolinite, and pyrite, as well as authigenic quartz were derived from the influx of hydrothermal fluids during different periods, from the authigenic to epigenetic. The paragonite in the coal may have been formed by the precipitated from Na-rich hydrothermal fluids. No effects of magmatic intrusion on mineralogy were investigated in this research.

Discussion of Hydrothermal Sedimentary Sequence in Baiyinchagan Sag of Erlian Basin,Inner Mongolia

Abstract: The lower Cretaceous hydrothermal sedimentary rocks had been found in Baiyinchagan sag of Inner Mongolia Erlian basin in recent years. The hydrothermal sedimentary rocks were rich in special minerals including clay sized albite,ankerite,natrolite,franquanite,barite,etc.,and were only developed in semi-deep to deep lacustrine facies.The hydrothermal sedimentary rock can also be characterized by its log response with extremely high GR( GR = 700 ~1 100 API),which is 2 ~ 4 times that of natural gamma value of normal argillaceous,and remarkably fluctuation in resistivity logging from as high as 2 000 Ω·m to 0.2 Ω·m. By the petrologic characteristics of the hydrothermal sedimentary rocks,the detailed analysis of single well core,combined with the corresponding logging response features,four hydrothermal actives can be recognized in Tenggeer-Douhongmu formation in the study area. One hydrothermal process will form a low natural gamma value lithologic section-the peak shape high natural gamma value cyclic deposition. A complete hydrothermal process consists of three stages: 1Early overflow process which precipitate low GR dolomitic or zeolitic fine grain rock with dolomite and zeolite laminae,zebra or interface layer. And 2Jet flow process with increasingly active hydrotherm. The laminae or interface layer of dolomite and zeolite will be deformed or even disrupted and result in dolomitic fine grain rock and clastic rock consisting of dolomitic or zeolitic intraclasts. After the energy of hydrotherm exhausted the hydrothermal activity will return back. 3Sluggish overflow stage and results in argillaceous dolomite rock and partial dolomitic mudstone with extremely high GR response.

Rift valley sedimentation and diagenesis, Tanzanian Examples - A review

Abstract: The main diagenetic events of polyphase rift valley successions are controlled by provenance geology, tectonic evolution and subsidence, weathering related to different episodes of fresh water flushing, and topographic and climatic effects. Based on the Tanzanian examples as case studies and comparisons with published studies on rift valley sedimentation and diagenesis, the main diagenetic phases of Tanzanian rift valley successions can be presented: 1. Early diagenetic precipitation of evaporites, hematite and calcrete along with feldspar dissolution, and in some cases formation of pore-filling clay minerals, zeolites and feldspar, may take place. 2. Middle diagenetic formation of albite, zeolites, chlorite, recrystallization of calcite and some quartz precipitation have been reported from several rift valley settings. Continuous subsidence results in enhanced recrystallization of calcite, with a trend towards larger crystal size and more poikilotopic configurations, and new generations of quartz and clay minerals such as e.g . illite. The precipitation of dolomite, ankerite and siderite have commonly been observed during this stage. 3. Late diagenetic processes is related to uplift and renewed tectonic activity. Under such conditions new generations of hematite, calcite and clay minerals were formed, partly as a result of feldspar dissolution caused by meteorically-induced fresh water flushing.

Corrosion of glass used for radioactive waste disposal – state of the art

Abstract: Iron corrosion products of the steel canister in the nuclear waste container are highly silica sorptive materials and very much expected to delay formation of the protective layer (gel) on the nuclear glass interface. This study is focusing on the role of the iron carbonates (ankerite), which is probably one of iron corrosion products and already exists in the clay structure of the disposal depth. French SON68 inactive reference glass (alternative to the R7T7- type) samples are planned to leach in different series of experimental models with dissimilar quantities of natural ankerite. All batch experiments will be cultivated in synthetic Callovo-Oxfordian groundwater; where different pH (4-9) values and temperatures (35, 50, 90 °C) are considered. In this paper the state of the art of the radioactive waste glass corrosion in the circumstances of deep geological disposal were extensively studied.