Metamorphism of mineral matter in coal from the Bukit Asam deposit, south Sumatra, Indonesia

Clay Mineralogy of Coal-Hosted Nb-Zr-REE-Ga Mineralized Beds from Late Permian Strata, Eastern Yunnan, SW China: Implications for Paleotemperature and Origin of the Micro-Quartz

“…Factors affecting formation of ordered I/S include temperature, fluid chemistry, time, source material composition, and permeability of the host rock [48,51,52]. In the present study, the latter three factors are unlikely to be the main controls on the ordering of I/S because most of the studied samples are mudstones derived from the same phase of alkaline volcanism with same magma source in the earliest Late Permian [1,2].…”

“…In addition to the sharp decrease of contents of kaolinite and berthierine, the ordering of their structure also starts to become poor (reflected by the broad peaks at 7 and 3.5 Å), along with an increase in the contents and ordering of I/S in X-11 to X-16 (Table 1; Figures 3, 4 and 7). The changes in contents and crystal ordering may reflect the re-forming of clay minerals under conditions that allow for the poorly-ordered kaolinite and berthierine to form [51]. While in the presence of K released from volcanic ashes, the conversion of well-ordered kaolinite to disordered kaolinite and I/S would have happened under hydrothermal conditions [51].…”

“…The changes in contents and crystal ordering may reflect the re-forming of clay minerals under conditions that allow for the poorly-ordered kaolinite and berthierine to form [51]. While in the presence of K released from volcanic ashes, the conversion of well-ordered kaolinite to disordered kaolinite and I/S would have happened under hydrothermal conditions [51]. The colloidal/infilling minerals which were precipitated from hydrothermal fluids revealed in part 4 and a previous study [2] suggest that hydrothermal fluids influenced the studied samples during diagenesis.…”

Potensi batubara untuk pengembangan gasifikasi bawah permukaan : Studi kasus Desa Macang Sakti, Provinsi Sumatera Selatan

“…Cekungan Sumatera Selatan merupakan salah satu cekungan yang penting dalam keterdapatan minyak dan gas bumi serta batubara (Amijaya and Littke, 2006;Susilawati and Ward, 2006;Daulay dan Santoso, 2008;Sosrowidjojo dan Saghafi, 2009;Badan Geologi, 2009;Susilawati dkk., 2015;(Friederich dkk., 2016). Direktorat Jenderal Minerba dan Batubara (2015) Cekungan ini berada pada suatu daerah tektonik aktif, sehingga lapisan pembawa batubara pada umumnya dipengaruhi oleh pelipatan, patahan, dan aktivitas intrusif dan ekstrusif.…”

On the fundamental difference between coal rank and coal type

“…between intrusions and coal seams (Gurba and Weber, 2001;Kisch and Taylor, 1966;Kwiecinska et al, 1992;Ward et al, 1989) to extensive areas of higher-rank coal within otherwise lower-rank coal deposits (Creaney, 1980;Daulay and Cook, 1988;Snyman and Barclay, 1989;Susilawati and Ward, 2006). Tectonically-driven geothermal fluids may also play an important role in coalification (Bayan and Hower, 2012;Gresley, 1896;Han et al, 1996;Hower and Gayer, 2002;Hower et al, 1993;Oliver, 1986Oliver, , 1992Ruppert et al, 2010;Uysal et al, 2000;Yang et al, 1996; among others).…”