Lignite oxidation under the influence of glacially derived groundwater: The pyropissite deposits of Zeitz-Weißenfels (Germany)
Abstract The Middle Eocene lignites of the Zeitz-Weißenfels coal mining area in central Germany hosted one of the most economically successful lithotypes of lignite deposits utilised in the paraffin industry of the 19th century, i.e. the pyropissite deposits. However, due to their economic significance, these rare lithotypes were almost completely mined out, such that presently only a few remnant deposits are known. Apart from the Zeitz-Weißenfels coal mining district, other pyropissite deposits were also encountered in other lignite mines, for instance, in the Hessian and Subhercynian Basins. Pyropissite is a whitish and bitumen-rich variety of soft brown coal (lignite) lithotypes, dominated by a homogeneous matrix with loosely embedded organic and inorganic components. Fresh exposure of pyropissite at Grana was logged and studied petrographically and geochemically, along with samples obtained from archival collections. Results were compared with those from the 19th and 20th century to derive general conclusions regarding origin and formation of pyropissite. Microscopically, the main constituent of this special lignite lithotype is amorphous to detrital in appearance. According to W. Schneider the term xanthinite is applied to this component, which forms the groundmass of the pyropissite. It contains high proportions of liptinitic substances with contributions of formless huminitic material and minor amounts of mineral matter. Geochemically, pyropissite is characterised by an increased H/C atomic ratio and a very high content of bitumen (in terms of toluene-soluble components) as well as low-temperature carbonisation tar. The obtained data revealed that the extraordinarily high content of liptinite and the paucity of huminitic material of the pyropissite deposits of the Zeitz-Weißenfels coal mining area are not related to primary depositional processes but rather are the result of dissipation of high condensed huminites and the consequent enrichment of liptinitic substances. The mechanism involves oxidation by groundwater and is related to glaciation processes operating during the Pleistocence. Such glacially derived processes also account for both vertical and horizontal distributions of the pyropissite. Thus, recent research activities may also serve as an innovative inspiration to fundamental understanding of the formation of lignites with extremely high liptinite content. Highlights Pyropissite is a whitish and bitumen-rich soft brown coal lithotype. According to W. Schneider the microscopical groundmass of pyropissite is termed xanthinite. Pyropissite can develop due to glacigenous alteration.
유료 다운로드의 경우 해당 사이트의 정책에 따라 신규 회원가입, 로그인, 유료 구매 등이 필요할 수 있습니다. 해당 사이트에서 발생하는 귀하의 모든 정보활동은 NDSL의 서비스 정책과 무관합니다.
원문복사신청을 하시면, 일부 해외 인쇄학술지의 경우 외국학술지지원센터(FRIC)에서
무료 원문복사 서비스를 제공합니다.
NDSL에서는 해당 원문을 복사서비스하고 있습니다. 위의 원문복사신청 또는 장바구니 담기를 통하여 원문복사서비스 이용이 가능합니다.
- 이 논문과 함께 출판된 논문 + 더보기