The cross bedded belt is a portion of LZa and a bit of LZb in the most deeply-exposed north end of the pluton, on Uttental lateau. Most of the crossbedding I saw was on the western side of the plateau, and maybe a bit in LZb on Kraemer Island across Uttental Sund from Uttental Plateau. The overall appearance of crossbedded rocks in the crossbedded belt is of cross beds like those seen in sand dune or fluvial sediments. Doubtless there are differences to the more knowledgeable, but it is clear that there were episodes of deposition and erosion of layers, rather different from the large trough structures that are essentially depositional features. These were interpreted by Irvine et al. (1992) as representing deposition following a hydraulic jump, where down-flowing currents along the walls met the floor.
Cross bedded gabbro in the cross bedded belt of LZa. Note truncation of layering indicating tops to the upper right.
Crossbeds in the crossbedded belt on Uttental Plateau, in LZa. View is looking east toward Wager,s Peak.
Channel fill and crossbeds in the crossbedded belt on Uttental Plateau, in LZa. Notice the small white autoliths near the base of the scoured surface.
Layered and crossbedded rock near the margin of the crossbedded belt, LZa, with several bodies of replacement anorthosite above a large, dark-brown trough, to the lower left, that truncates layers.
A small replacement anorthosite, this one sub-parallel to some layering, and having a mafic layer on the bottom (left). In the lower half of the image there are several dark layers truncated against another dark layer.
