. The geology of the goldfields of British Guiana. anitite of adecidedly gneissose character. The rock is grey in colour, and some-what coarse in texture. At Yakiri Creek it is crossed by an intrusivedyke of a fine-grained biotite-diorite, the outer parts of which, where incontact with, or close to, the granitite, show well-marked schistosity,due to fluxion in the pasty mass during its intrusion. At Uropocari Rapids the gneissose granitite, which is similar to thatat Eclipse Cataracts, is traversed by many narrow veins of intrusivebasic rock. Near to these the granitite is altered, and shows a
. The geology of the goldfields of British Guiana. anitite of adecidedly gneissose character. The rock is grey in colour, and some-what coarse in texture. At Yakiri Creek it is crossed by an intrusivedyke of a fine-grained biotite-diorite, the outer parts of which, where incontact with, or close to, the granitite, show well-marked schistosity,due to fluxion in the pasty mass during its intrusion. At Uropocari Rapids the gneissose granitite, which is similar to thatat Eclipse Cataracts, is traversed by many narrow veins of intrusivebasic rock. Near to these the granitite is altered, and shows a foliatedstructure. Near Duquari Creek, for a distance of about one and a half miles,the granitite is traversed by a dyke of epidiorite, which, in parts, has amassive structure, and in others a schistose one. Above Duquari Creek the Arawatta rocks form a marked featurein the scenery of the river. They consist of a grey-coloured, fine-grained,^aieissose granitite, which rock is also exposed at intervals for about two Plate 9. [_To fac? page lOS. i. ARAWATTA ROCKS (GRANITE), BARIMA RIVER,NORTH-WEST DISTRICT. Foto hi/ H. I. Pei-kin> ») Geology. 109 and three miles further up the river. A red oneissose granite occursbelow Wanaparu Creek, and in it intrusive veins of pinkish aplite simihir aplite is seen in a grey gneiss opposite to Wanaparu Creek,and again in red gneissose granite which the river traverses for aboutfour miles above the mouth of the Mehokowaina Creek, while an apliteis intrusive in grey gneiss near Five Star Landing. The gneissnear Wanaparu Creek is a hornl)lende-graiiitite-gneiss. About threemiles above the junction of the Mehokowaina Creek the red gneissosegranite is traversed by a white-spotted, dark-grey efjidiorite, which, inplaces, shows a somewhat schistose structure. Similar more or lessschistose rocks traverse the grey gneiss and the gneissose granitesin many places between here and Five Star Landing. Some eightmiles below Carriage
Size: 1785px × 1400px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, booksubjectgeology, booksubjectp
