April 20, 2001
Field Trip Report
Stop 1: was at the exposures occurring northward along
Kentucky 2 at the junction with I-64. This outcrop shows signs of having pure
orthoquartzite and some sandstone that are very similar to what you would find
on a beach. Initial guesses are that there is cross bedding which leads to
the conclusion that this area was once a flood delta. There is eroding into
the cross bedding surface. Units above this surface may have been reworked because
of the huge area of deposition. Other guesses are that these are barrier islands
stacked on top of one another and there is a breaking slope along the margin
of the outcrop meaning that there is also a ravinement surface. The grains
along this outcrop are sub-angular to rounded grains, which are found in beaches
and wind blown areas. The sediments looked to be reworked by tidal currents.
Stop 2: This outcrop was experienced some cutting and filling based on the continuous sheets that have uniform sized grains. The sheets could have been created by three possiblites: a flood delta, tidal flat being worked or sediment splays.
Stop 3: This outcrop has upper Mississippian limestone, Upper Carboniferous to Lower Carboniferous sediments. This outcrop is mostly shallow water limestones. There is also lime mud that is well sorted and the sediment grains have been reworked.
Stop 4: This outcrop is in the Ordovician. The outcrop was moving to a tectonically active area (margin). The interior beds formed in 60-70 feet waters. The muds, assorted carbonates, and wide shelf margins came through and reworked the bottom of shelf as the base level changed.
Stop 5: This outcrop is Silurian in age. The waters were shallower leading to dolomizated on the surface. There are Nodules and Stramatapolids. Shale started to form in this period because of a shallow water environment indicated by a red coloring in a restricted environment. An example of this would be the Bahamas.
Stop 6: This outcrop is in the Deltaic Mississippian. This outcrop displays signs of sub-marine rocks, because of the variations in the rates of flow and supply to the compacting layers. (i.e. Thickening & Thinning of layers)
Stop 7: This outcrop has changed in depositional system. The sediment is coarsening upwards which leads to the possiblites that the system is a Delta Shoreline or a Barrier Coastline. The reasoning behind this is two-fold: 1) no transportation mechanism (transport picks up as we move to the shore.) 2) Transportation by rivers brings in coarse sediments.
Stop 8: This outcrop has Burrows and fossils. This means that we are going into shallowing waters, which is about 30 to 40 feet high. Iron-rich sediments bring oxidization at the time of deposition creating a red color. There is reworking at the bottom of the outcrop with cutting and filling. There are also vertical and lateral burrows along with other fossils.
Stop 9: This outcrop has alternating shale and sand layers, which means it's a distributing mouth bar. The pattern is like this: shale/sand/shale/sand…ect. Above this slope is a shale layer and over that is a channeled mouth bar. A Levee is on top of this and is dipping from right to left. The Coal layer is on top of this representing the final bay fill.
Stop 10: This outcrop is on the Appalachian Thrust zone/ Alajaines Formation in the Pennsylvanian. The lower part of the road cut show large continuous sandstone with some channeling meaning that it's a Distributing Mouth Bar. There are alternations of sandstone and shale leading to the conclusion of a Bay or ProDelta. There is a sharp contact of overlying sands with evidence of a point bars. Also very continuous sands which means there was once a bay present.
Stop 11: This outcrop is in St. Paul, Virginia. This outcrop is Cambrian in age. There are siltstones and limestones (but mainly limestones), and a series of small bolboss features.
Stop 12: This outcrop is in the Ordovician Margin. There are crinoids, grapestones, stramatoporids, and calcite crystals in the outcrop formation. There are layers and banks of crinoids, which means the possibity of a beach environment. This outcrop was in a high-energy system (maybe intertidal channel). The beds were possibly soon replaced by lime mud with different faunas, bryozoans, brachiopods, echrons, and corals.