X. Querol et al., GEOLOGICAL CONTROLS ON THE COAL QUALITY OF THE MEQUINENZA SUBBITUMINOUS COAL DEPOSIT, NORTHEAST SPAIN, International journal of coal geology, 29(1-3), 1996, pp. 67-91
Citations number
48
Categorie Soggetti
Mining & Mineral Processing","Geosciences, Interdisciplinary","Energy & Fuels
The results of geological, petrographical, geochemical and mineralogic
al studies, performed to determine the coal-forming paleo-environmenta
l conditions which gave rise to anomalous enrichments in organic sulph
ur, molybdenum and uranium in the Oligocene Mequinenza subbituminous c
oal deposit of northeastern Spain, are summarized. This paper demonstr
ates the major influence exerted by the paleohydrology of the depositi
onal framework on the early diagenetic evolution of the precursor peat
deposits. The S, Mo and U enrichments, the preservation of aragonite
and chlorophillinite, and the high degree of gelification of the Mequi
nenza coal are a consequence of alkaline syngenetic conditions in the
depositional environment. Similar conditions can be inferred for many
Mesozoic and Tertiary coal deposits in the Mediterranean region (Mallo
rca, Sardinia, Hungary, Bulgaria, Serbia, Greece and Turkey). However,
the source of sulphur may have been different and have included Trias
sic and Early Jurassic sulphate recycling scenarios or volcanic source
s, Whatever the source, sulphur enrichment is always influenced by the
alkaline depositional environments developed in basins generated duri
ng the Alpine Cycle in circum-Mediterranean mobile belts.