1、附 录ACoal forming environments and their relationship to tectonic activity in the Cevennes Stephanian coal basinDennis L. Nielson GammaThe Stephanian C6vennes coal basin is located in the southeastern part of the French Massif centra1Previous studies focused on its stratigraphy，sedimentary petrology，
2、coal chemistry ， coal petrology and structural geology. The aim of this study is to highlight the relationships between the tectonic patterns and the sedimentary environments of coal formations in the late Hercynian interm ontane basins of the Massif central in France , resemble the Tertiary coal ba
3、sins in China where the occurrence, distribution and the thickness of the coal seams are essentially controlled by early tectonic activity 1.Regional framework of Cevennes coal basin The coal measures are up to 2500 m thick and outcrop in the northern part of the basinMesozoic strata cover the steph
4、anian series in the southern basinThe two main faults Villefort and Crvennes borde the 50km2 wide coal basinThe basin is divided into a western (study area)and an eastern subbasinsThe western subbasin was investigated in this study is divided with three areas，respectively from north to south：La Vern
5、arede graben， Portes horst and La GrandCombe graben，by the Paulin and Chamarit faultsThis paper focuses on the characteristics and distribution of the coal and clastics distribution in the northwestern part of the Crvennes coal basin，their palaeoenVimnmentale setting and their relationships with the
6、 early tectonic activity 2.Stratigraphic famework The Stephanian series of the basinfill sequence are dominated by detrital rocks including conglomerates or breccias，coarse and fine grained sandstones，sihstones，mudstones and coal seams The depositional sequence canbe divided into six lithostratigrap
7、hic units from bottom to top ： Strriles infde La ForSt unit； Ricard unit； Strriles supde La Foret unit； GrandBaume unit； Luminieres unit； Champclauson unitThe stratigraphic framework is a result of the distribution of various depositional environments and their mutual relationships Besides the margi
8、nal faults，intrabasinal faults such as the Peyraube fault and Malperthus fault also controlled the distribution of units，and the development of asymmetric grabenTh at the distribution of the coarsegrained bodies an d coal seams，in both the lower and the upper parts of the sequence are related to the
9、 marginal and intrabasinal faultingThe important mineable coal seams are concentrated in the middle part of the sequence 3.Coal bearing sequences in the Cevennes basin The analysis of coal bearing sequences presented here is based on a large amount of geologiical field sections drill cores and well
10、logs complemented by sections in ancient mining galeriesThe paleogeographical and paleoen vironmental interpretations were performed using farther inform ation derived from thin section observations and statistical processing of sedimentological dataCorrelations within the basin are discussed using
11、poor biostrati graphical data and genetic stratigraphy induced sequences.31 The first stage：deposition of the Strriles infde la Foret unit The Strriles infde la Forget unit form ed at the beginning of the opening of the sub-basinMainly alluvial fan systems started at the center of the La Grand-Combe
12、 grabenThe near-fan and middle-fan deposits are dominated by breccias，conglomerates and coarsegrained sandstones，containing gneiss and quartz fragments with a maxdiameter up to 40 cmNear-and middlefan mainly developed in the west part of the study area，close to the marginal Villefort fault and advan
13、ced eastwardThe far-fan was dominated by sandy and muddy sedimentsIn the eastern basin alluvial fans are poorly developed，and consist of finegrained sediments，except close to the Peyraube fault where some small fan conglomerate bodies were depositedDuring this stage，the Peyraube fault and together w
14、ith the western marginal faults，controlled the distribution of the various sediments 32 The second stage：deposition of the Ricard unit The deposition still occurred in the La Grand-Combe graben，but extended both towards eastwards and west-mentwardThe fan conglomerate，well-developed along the western
15、 margin，drew back to the Villefort fault，with decreasing of both deposition area and thickness of the seriesThe farfan，composed of sandy sediments，developed at the eastern and western margins of the La Grand-Combe graben and widened along a NESE directionIn the central part of La Grand-Combe graben，
16、swamps developed in forefan plain position，with peat enrichment in the central part of the swampThe peat enrichment zone is just covering the underlying extra-thick fan-conglomerate of the Strriles infde la Foret unitThe corresponding thick coal seams thin rapidly an d pinch out both eastwards and westwards and also split westwards，along the Peyraube fault, which controlled the development of the coal enri
