固体沥青在喷出岩中是很少见到的。发生这种矿化的地区是由上石炭纪的喷出沉积岩的两组岩系组成的。下部岩系通常发育着成互层的透镜体夹层,其岩性为黑色页岩、泥质碳酸盐页岩、合沥青的碳质页岩以及紫红色的凝灰岩、凝灰质砂岩和凝灰熔岩。这些岩石常挤压成为褶皱,并夹有喷出的流纹斑岩岩墙。后者部分地转为上复层。 Solid bitumen is rarely seen in shotcrete. The area where this mineralization occurred consisted of two series of rocks that emplaced sediments from the Upper Carboniferous. The lower part of the rock series usually develops interbedded lens interlayers with lithologies of black shales, shaly carbonate shales, cohesive asphaltic shales, and fuchsitic tuffs, tuffaceous sandstone and tuff lavas . These rocks are often crushed into folds, with exuded rhyolite porphyry walls. The latter is partially converted into upper strata.