St. Francois Mountains

The Lynne deposit lies within the early Proterozoic Penokean fold belt of the southern province of the Precambrian Shield. The fold belt is divided into two major terranes in Wisconsin (Sims 1989). The first is the northern Penokean terrane, which contains major oxide facies iron formations and granitic intrusions (DeMatties 1989). The second major terrane, separated from the Penokean terrane by the Niagara fault zone, is the Wisconsin magmatic terrane, characterized by a volcanic island arc-basin assemblage (Sims 1989). This southern terrane lacks major oxide facies iron formations, but contains abundant tonalite-granite intrusions (DeMatties 1989). The Wisconsin magmatic terrane is further subdivided into the northern Pembine-Wausau terrane and the southern Marshfield terrane, which are separated by the Eau Pleine shear zone, a north-dipping subduction zone (Sims 1989).

Silicious lava, forced up from deep down below. Soda trachytes extruded in a highly viscous state, building the steep-sides mametons we see in Hanging Rock. And quite young, geologically speaking. Barely a millions years old. (Greene, 11)

This formation is a very fine grain Mississippian limestone. To test to see if this was the Bangor formation we used HCL and because there was a reaction we know its limestone. This formation could also be described as gray in color as well as an average thickness of 700 feet. We see the Bangor until stop eight, where we see a very different vertical bedding. Also different at stop eight is the outcrop no longer reacts with HCL. From this we gathered that we had moved into the Hartselle formation. In the Hartselle Formation, Mississippian aged sandstones are dominant. This particular stop had a large amount of jointing. After the Hartselle, we figured the Pride Mountain Formation would be next, however at stop nine we see the Maury Formation present. This stop focused on the rock located inside the creek. Because we were unable to go into the creek to get the strike and dips, we once again had to do a projected orientation. Also found on this stop were natural sulfur springs, easy to notice with the smell that it gives off. The Maury formation consist of Mississippian- Silurian aged shale. At the next stop, stop 10, we encounter the Ft. Payne formation. Although this area location was thickly vegetated, we were able to conduct the acid test and saw that the HCL reacts in some places but not all. From this we concluded that this was the cherty limestone of the Ft. Payne formation. The following stop, 12, we went up section and arrived at the Maury Formation once again. At the final stop, location 13, we see Ft. Payne Formation. All of the metamorphism and deformation in the southernmost Appalachians can be related to the movement of the thrust sheets and stacks (Higgins,

With our observation of the Shawangunk formation, we see a sedimentary rock formation containing a range of grain size. Such sizes range from pebbles (3cm-5cm), fine-grain sand, and medium-grain sand. There is some grading towards the bottom left of the outcrop known as a reverse grading with some small cross beds present (Figure 2). The grading occurs towards a slight part of the outcrop where we see the grading beginning as fine grain sediments and working up to coarser grain. With moderate sorting we see variations of degree of sorting per bed. As the degree of sorting varies as does the sphericity. The sediment bedding is well seen ranging in sizes of +/--20 cm to 40 cm. This outcrop has thick beds as one can see the basic units with cracks in between each (Figure 3). With mostly tabular beds consisting of sub-angular, and sub-rounded sediments, this outcrop also consists of some ventricular beds (Figure 4). When looking at figure 4, we have a small space of a ventricular bed present. This is because the bed comes in, pinches thicker bedding,

Starved rock and St. Peter Sandstone are an erosional remnant of Ordovician period. These remnants contain Pennsylvanian clastics that survived the washing out of the Illinois River at the end of the Ice Age. Evidence for swift, turbulent, and deep water includes gravel bars and erosional features as high as 160 feet above the current level of the river, massive cross bedded sand, and gravel deposits along the river course.

The youngest of these rocks are dated at about 220,000 years ago. Rhyodacties and quartz latites in the modern caldera area extruded from about 320,000 years ago to 260,000 years ago, and then silica-rich rhyolites at Glass Mountain northeast of the caldera erupted from about 210,000 years ago to 80,000 years ago. The scattered distribution of the initial mafic eruptions indicates that they were erupted from the mantle, while the slightly younger domes and flows were from a deep-crustal source. The youngest rhyolite eruptions erupted at the northeast rim of the caldera at Glass Mountain and were the first activity of the silicic Long Valley magma chamber (Bailey, et. al., 1989).

A description of the grand canyon rock layers would include the Colorado River running at the bottom of the inner gorge with flats on both sides which consist of tapeat sandstone layers. There is also the Vishnu Complex, consisting of rocks that have been changed by heat and are buried at the lowest layers. These are tilted and are called the “Grand Canyon Supergroup” the Grand Canyon supergroups are at least 12,000 ft in thickness. These rocks or (the “Inner Gorge”) are usally steep and narrow with hard deep cuts in the lower tilted layers which raise above sea level.

The land rose up and created a precipitous eastern edge of the batholith and a gentle western edge. 10 million years ago, uplift, which is the vertical rise of Earth’s surface due to natural causes, started to occur and accelerated quickly. Soon, the Sierra Nevada Mountain Range that we know today towered 14,000 feet in elevation. Throughout uplift, cracks formed in the granite of the mountains. They formed due to the pressure that came with the uplift. The erosion that stripped away most of the overlying rocks caused the remaining rock to expand and crack. These cracks are still forming today and they provide a template for future erosion.

These rocks grade abruptly northward into a marine geo-synclinal facies up to as much as 6,000 feet thick in the Las Vegas sub-basin. The Magdalena Group is missing from the Cimarron arch, but it most likely present in the western part of the northern Raton Basin. Orogenic debris of the Sangre de Cristo Formation of Pennsylvanian and Early Permian age was derived mainly from the San Luis uplift, filled the Rowe-Mora and Central Colorado basins, and lapped onto Precambrian rocks of the other bounding uplifts. The Sangre de Cristo Formation is 700-3,500 feet thick at the south, and 6,000-9,500 feet thick at the north (Baltz 1965).

It is currently the largest exposed granite in the world weighing approximately one trillion pounds; although, only one third of the mountain can be seen as a majority of the mountain expands below ground as far as North Carolina. The enormous pluton mountain, as scientifically identified by geologist, was formed by a complex folding and faulting that had subsequently created the Blue ridge mountains. Though what remains as a mystery to many geologist is as to how such a massive granite mountain has become exposed. Although there are several theories that have been publicated to explain such a phenomena none are substantial or advocated the most. While the origins of Stone Mountain are elusive, the correlations of this landmarks with american history are intricately

The Grand Canyon has plenty of volcanic rocks near the bottom and the top. ICR, Institute for Creative Research, has been involved in a project for years to date these volcanic rocks. this study has come a long way to show that many of the Grand Canyon strata could have formed rapidly, and that the erosion of the Canyon by the Colorado River has not been going on for millions of years.

The geology history of the northern Bonaparte Basin have been described by [12,13,14,15,16,17,18,19,20,21] and are summarised by [22] and is associated with three main phases of rifting. The oldest was initiated in the Paleozoic and has a northwesterly trend. Overprinting this is a Permo-Carboniferous episode of rifting, which created a northeasterly structural grain. A later phase of rifting related to ‘break-up’, was initiated as early as the Late Triassic, but has its main expression from the Callovian to Kimmeridgian syn-rift (Figure 2). A number of significant regional discontinuities are recognized in the Middle, Late Jurassic and Early Cretaceous sequences, related to the effects of sea level fluctuations and ‘break-up’ along the north-western

“The Three Rondavels are located in the Blyde River Canyon region” Anon (2006). These Three Rondavels are round mountains with peaks that are formed in a shape of an African Hut. They attained this shape as a result of erosion agents. The soft rocks that are found on the upper surface are removed leaving the tough rocks such as quartzite shown,

A seismic section shows the appearance of the SGA-A across (Figure 23) that goes across a salt dome inducing faults (Figure 23b) that go through the Chalk group and segments the accumulation of gas within the shallow sub-section below Quaternary incised Tunnel Valleys. There seems to be a seismic indication of a vertical migration of hydrocarbons along faults reaching the SGA - A accumulation that may indicate migration pathways for fluids above a salt diapir – C.

The upper Miocene strata are conformable, with no evidence for faulting or extensive erosion during the intervening period (~24 to ~11 Ma). The pre-rift flood volcanics and syn-rift units show a regional SE dip. The contact between Megezez and flood volcanics can be traced in imagery throughout the region (from Wolfenden et al, 2004).