Figure F34. Photomicrograph of Sample 183-1137A-45R-1 (Piece 1, 80-84 cm) from the breccia at the top of basement Unit 10 showing the glassy to aphanitic textures of basaltic clasts. The clasts have angular polygonal shapes with some curviplanar surfaces, and there is evidence of breakage across some crystals and through vesicles. However, breakage seems to preferentially take place through the glassy parts of the basalt. Penetrative brecciation can be caused by the dynamic injection of fluidized sediment disrupting quenched clasts. Field of view = 2.75 mm (plane-polarized light).