GEO 205X
GEOLOGICAL MAPPING

During the GEO200F Course in Second Year the class spends 10 days in the field at Laingsburg
[Photographs courtesy of Dr John Rogers and students Clementine Clark and Penelope Price 2001]

 SE of Laingsburg: E-W-striking folded strata of the Cape and Karoo Supergroups, E of Tertiary peneplane.

Aerial photo of UCT's Colenso van Wyk Field Station, W of tar road, but E of centre of photo, SE of Laingsburg.
Close-up of aerial photo of the terrain around the Colenso Van Wyk Field Station (white buildings E of stream). View to S of the Colenso Van Wyk Field Station with header tank E of main buildings.
View to W along strike of Dwyka Gp clast-rich tillite ridges, S of overturned and thrusted anticline of Witteberg Gp. View to E of the Colenso Van Wyk Field Station along the axis of a syncline in the Ecca Group's Prince Albert Formation.
View to E to the Colenso Van Wyk Field Station along the axis of a syncline towards the Floriskraal Dam. View to S towards the Tertiary peneplane beyond road (N1) and rail bridges across the Buffels River at Laingsburg.
View to E from Tertiary peneplane to Witteberg Gp mountains, Dwyka Gp hills and Ecca Gp hills around Floriskraal Dam. View to E along strike of N limb of overturned and thrusted anticline in the Witteberg and Dwyka Gps N of dam.
View to E of overturned anticline of the Witteberg Group's Floriskraal Formation on left (E) bank of the Floriskraal Dam. View to S, W of Floriskraal Dam.  N of Witteberg Gp mountains, Dwyka Gp flanks Ecca Group along syncline axis.
View to S across syncline (Dwyka-Ecca-Dwyka) to Witteberg Gp mountains, W of Floriskraal Dam. View to S across ridges and valleys of folded Dwyka Gp strata to Witteberg Gp mountains, west of Floriskraal Dam.
View to W of tightly folded Witteberg Group sandstones and shales beside the Laingsburg-Ladismith road. View to S of western nose of E-plunging syncline in Ecca Gp (Prince Albert, Whitehill and Collingham Fms).
View to E from tar road of Wittebrg Gp's Floriskraal Formation with distinctive sandstone ridges flanking shales. View to S of Rooinek Pass, cut through overturned quartzites of the Witteberg Gp's Witpoort Formation.
View to SW of clast-rich tillite ridges of the Dwyka Gp, N of the Witteberg Gp mountains and NE of the field station. View to E of parasitic folding in the Ecca Gp's Prince Albert Formation in roadcutting NE of field station.
View to E of a small anticline developed in the Ecca Gp's Prince Albert Formation in the roadcutting NE of the field station. View to E of parasitic folding in the Ecca Gp's Prince Albert Formation in roadcutting NE of the field station.
Dr Chris Hartnady instructing second-year UCT students on the finer points of deformed Prince Albert Fm strata. View to E of overturned, near-vertical quartzites of the Witteberg Gp's Witpoort Formation below Floriskraal Dam.
View to W of N-dipping distal turbidites of the Ecca Gp's Laingsburg Fm, SE of Laingsburg.  Note infilled channel. View to NE of an asymmetric anticline in the Ecca Gp's Laingsburg Fm on the left bank of the Buffels R, N of Laingsburg.
View to E, in Rooinek Pass, of thick-bedded quartzites of the Witteberg Group's Witpoort Formation. View to E of an asymmetric syncline in sandstone strata of the Ecca Gp's Floriskraal Fm, due S of Laingsburg.
View to E of boulder bed, dipping steeply to N, between Units 1C and 2C on the right (E) bank of the Witbergs River. View to E of Dwyka Gp (Units 1C and 2C) dipping steeply to N on right (E) bank of Witbergs River.  Note rock cleavage.
View to E (Witbergs R) of rock cleavage, subvertical to steeply dipping boulder bed between Dwyka Gp's Units 1C and 2C. View to S of angular dropstone cobble depressing laminae in laminated tillite of the Dwyka Gp's Unit 3F, NW of camp.
View to S, in a kloof, of a large boulder of garnetiferous augen gneiss within the Dwyka Gp's Unit 3C, west of Blouwaterval. Closeup of the garnet augen in the gneiss boulder embedded in the Dwyka Gp's Unit 3C in a kloof west of Blouwaterval.
Angular boulder with glacial striations, liberated by weathering and erosion from the Dwyka Gp's Unit 3C. View to N of a glacially striated boulder , released by erosion from the Dwyka Gp's Unit 3C NW of E-plunging syncline's nose.
Exotic cobble of green amygdaloidal andesite of the Venterdorp Supergroup on the left (W) bank of the Witbergs River. View to S of dropstone pebble in tillite of the Dwyka Gp's Unit 3F, N of the nose of the plunging syncline.
Brown calcite concretions in the Dwyka Group's Unit 4F, which exhibits pencil-weathering. Dropstone pebbles in laminated tillite of the Dwyka Group.
Dropstone pebble in laminated tillite of the Dwyka Group. View to S of polymict cobbles of quartzite and granite suported in the Dwyka Gp's Unit 3F, NW of the field station.
View to S of angular dropstone cobble in laminated tillite of the Dwyka Gp's Unit 3F, beside stream NW of field station. Cluster of dropstone pebbles in Unit 2C of the Dwyka Gp on the right (N) bank of the Witbergs River, due S of Laingsburg.
View to E of N-dipping deltaic sandstones and shales of the Ecca Gp's  Waterford Fm on S limb of syncline, SE of Laingsburg. Rectilinear jointing and Leisegang weathering in mudstones of the Ecca Gp's Collingham Formation.
Multiple colour zoning developed during weathering of strongly box jointed Dwyka shales Dwyka Tillite exposure showing horizontal bedding and a vertical cleavage
Plunging fold closure exposed at the surface Dome shaped bedding surface exposed in an outcrop of a plunging anticline
Closeup of Leisegang weathering in rectilinear-jointed mudstones of the Ecca Gp's Collingham Formation. Variably cemented mudstones of the Ecca Group's Prince Albert Formation.
Outcrop scale thrust structure with the sense of movement indicated Small fault developed in thinly bedded strata
Striated surface produced by the early Karoo Dwyka glaciation View to E N1 just E of Laingsburg, showing steeply S-dipping, rippled turbidite in the Ecca Gp's Laingsburg Fm.
Symmetrical oscillation-ripplemarks in the Ecca Group's deltaic Waterford Fm in kloof on NW edge of the study area. Modern (Holocene), mud-draped, symmetrical oscillation-ripplemarks in a dessicated stream in the Laingsburg area.
View to N of sole markings on base of N-dipping turbidite (Bouma ABC)(Ecca Gp's Laingsburg Fm) beside Witbergs R. View to E of bifurcating, symmetrical ripplemarks on steeply dipping sandstone bed of the Ecca Gp's Floriskraal Fm.
View to N of N-dipping turbidite bed with sole markings in Ecca Gp's Laingsburg Formation on left bank of Witbergs River. View to N of N-dipping turbidite bed with sole markings (flute casts) on its base, acting as palaeocurrent indicators.
View to N of N-dipping turbidite bed with sole markings on its base, left bank of Witbergs River. View to N.  Close-up of sole markings (flute casts) on previous photographs.  Palaeocurrent direction towards NE.
Close-up view of current-rippled upper bounding plane of ?Laingsburg Formation (Ecca Group) beside N1. View to N.  Close-up of sole markings on base of turbidite in Ecca Gp's Laingsburg Fm on left bank of Witbergs River.
Symmetrical oscillation-ripplemarks on sandstone bed in shales of the Floriskraal Formation. Second-year geology students (2001) in front of the Colenso Van Wyk Field Station, SE of Laingsburg.