Geological Report on the Chibougamau Mining Region in the Northern Part of the Province of Quebec Volume 923 (Paperback)

This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1906 Excerpt: ...phases of one irruption. Their coarse crystalline texture points to slow cooling at a considerable depth below the surface, while their contact with the diabase schist shows that they penetrate the latter and are consequently newer in age. The largest mass of these rocks is irregular in shape and extends westward from Sorcerer mountain and the northeast part of Chibougamau lake across Dore lake to Simon lake on the Chibougamau river. The second large mass is about three miles wide and extends for several miles east-and-west along the north side of Opemiska and Mikwasach lakes. The acidic irruptive rocks are represented by three different granites. The oldest of these--a red to pink, hornblende-mica-granite--is seen about the northeast, part of Wakonichi lake beneath the Lower Huronian conglomerate, most of whose boulders are derived from this granite. Hornblende-A second hornblende-mica-granite is found on the west side of?nica-granite. this lake where it cuts the conglomerate and its associated diabase schist, and is, in consequence, of Post Lower Huronian age. This granite is lighter in colour than the preceding and its hornblende is often decomposed to sericite, causing the rock to become a protogene granite. The Wakonichi area probably extends several miles westward and may be connected with the small exposure of granite seen on the Chibougamau river a few miles below Asinitchibastat lake. A large area of similar granite is found in the southern half of Chibougamau lake and extends westward thence across the southern half of Dore lake. It is again seen on the second lake-expansion of the Chibougamau river and then on the western shores of Simon lake and from there to the west sidt of Asinitchibastat lake. Granite of this type is next met with on the sou...