1. Chert conglomerate
General Atlantic, Tjaden 1A1 WIW #1, 4323.5 ft, chert conglomerate containing clasts of oil-stained chat and chert in silty, clay matrix with smaller chert clasts. Scale bar is 2 cm. Thin section photomicrograph, 4322.5 ft, from inside chat pebble containing abundant molds of sponge spicule and small vugs filled by blue epoxy. Porous microcrystalline quartz and microcrystalline calcite (stained with alizarin-red) comprise matrix, replaced by patches of megaquartz (white). Irregular vugs cross cut other fabrics. Scale bar is 0.1 mm.