Comparative study on geochemical characterization of the Carboniferousaluminous argillites from the Huainan Coal Basin, China

Abstract

Aluminous argillites were widely deposited in the Taiyuan Formation at the Huainan Coalfield at the southeast margin of the North China Plate. However, knowledge about their formation conditions and geochemical characterizations is not presently known. We recovered underground aluminous argillites at depths of 485-610 m from a borehole in the Zhangji Coal Mine and characterized their geochemical parameters, including major and trace elements, by X-ray fluorescence, inductively coupled plasma optical emission spectrometry, and inductively coupled plasma mass spectrometry. The provenance, climatic conditions during the weathering process of parent rocks, weathering extent, and depositional environments of Huainan aluminous argillites were investigated. Results show that Huainan aluminous argillites are depleted in alkalis and alkaline earth elements and enriched in Al, Fe, and Ti. The ratios of immobile trace elements such as Nb/Ta and Zr/Hf are similar in all the argillite samples. The NASC-normalized rare earth element (REE) patterns of the argillites show an enrichment of heavy REEs and depletion of light REEs, with positive Ce and negative Eu anomalies. The provenance analysis indicates that the studied aluminous argillites probably derived from the common parent rocks composed of felsic to intermediate igneous rocks. These argillites were presumably deposited under anoxic environments.

Geochemistry and multivariate statistical evaluation of major oxides, trace and rare earth elements in coal occurrences and deposits around Kogi east, Northern Anambra Basin, Nigeria

“…4). This reflects predominantly basalt to granite rocks as the source of the terrestrial sediments that form part of the coal (Amajor 1987;Chen et al 2016).…”

“…10). This indicates that both weathering of source rocks/materials and conditions surrounding the coal formations occurred in humid climatic environments (Chen et al 2016;Schellmann 1981).…”

“…The Si becomes unstable in rocks due to removal of silica rocks as weathering progresses. According to Chen et al 2016, the SiO 2 -Al 2 O 3 -TFe 2 O 3 (SAF) ternary diagram proposed by Schellmann (1986) can be used to quantify the degree of laterization. On the basis of the SAF Fig.…”

“…Provenance diagram of Al 2 O 3 versus TiO 2 in coal (after Amajor 1987) Provenance diagram of TiO 2 versus Zr in study area (afterHayashi et al 1997) marine or brackish water influences, saline lakes or inorganic matter enriched in algal remains(Stanislav et al 2010).According toChen et al (2016), Al 2 O 3 and TiO 2 in source rocks are preserved in the clastic sedimentary rocks…”

Geochemical evaluation of Campanian-Maastritchian clay-shale sediments of Patti formation, Southern Bida and Mamu Formation, northern Anambra basins

“…Provenance of the Clay-Shale deposit Sr/Ba ratio have proven to be a very important tool employed by previous studies to estimate paleo-salinity (Chen et al, 2016). Sr/Ba ratios >1, 0.5-1, and < 0.5 propose seawater, brackish water, and freshwater conditions, correspondingly ( Li et al, 2018).…”