The JUNIATA JOURNAL of GEOLOGY, 1, 1-7 (2014)

Original Article Identifying the Distinct Rock Types in the Streambed of Muddy Run

Kristin N. Kopera

Pennsylvania has many secondary and bedrock streams, and one such stream is Muddy Run. Muddy Run is located primarily in the Hamilton Formation, but also touches the Onondaga and Ridgeley Formations in Huntingdon County, Pennsylvania. This paper identifies the rock types that are currently in Muddy Run, and matches them to the local geologic formations. Instead of primarily finding Hamilton Group in the stream, the majority of the samples taken from Muddy Run were from the Tuscarora and Ridgeley Formations. This suggests that Muddy Run had, at one time, come in contact with the Tuscarora formation. This data could also suggest that Muddy Run once belonged to a larger stream that transported the Tuscarora sandstones and deposited them in Muddy Run’s current location.

Keywords. — Bedrock Stream; Onondaga Formation; Ridgeley Formation; Meandering River; Tuscarora Formation

Department of Geology, Juniata College, 1700 Moore Street, Huntingdon, PA 16652. Email: [email protected]

INTRODUCTION Huntingdon County, Pennsylvania, is one such example. Bedrock streams, instead of just Rivers and streams are the main transporters of flowing over the ground, cut down into the local sediment and rock and they are known for their bedrock (Seidl & Dietrich 1993). This following powerful erosional capabilities. Sediment and paper will answer two questions concerning rock travel down gradient from location to Muddy Run. Firstly, throughout its geologic location until they come to rest in a delta history, from what locations has Muddy Run .Alternatively, the sediment could also be been eroding and transporting rock? In addition, deposited when the velocity of the water has where did the rocks in Muddy Run once belong become too slow to move the debris any farther. and how far could they have possibly travelled? Secondary streams, although known for moving This is an important question to answer because less sediment or rock, still retain the power to it would help geologists construct a more erode and transport. Muddy Run, a secondary complete history of the Huntingdon area. By bedrock stream in Oneida Township, knowing where the rocks in Muddy Run MUDDY RUN ROCK TYPES

originated from, they can track the movement of Muddy Run or determine what streams have had an influence on this tributary.

Muddy Run passes through Huntingdon, running through the Juniata College campus. Its catchment lies in a valley at approximately 700 feet elevation in the majority of locations. The down cutting of bedrock streams, such as Muddy Run, created the topography of the current landscape (Seidl & Dietrich 1993). This Figure 2. A satellite image of Huntingdon, bedrock stream is separated from the Juniata Pennsylvania, the white line indicates the sampling River and Standing Stone Creek by ridges on location on the Juniata College campus. either side of the valley (Figure 1). In addition, Mahantango and Marcellus formations. the valley is also formed by the south east slope Specifically, Marcellus shale makes up the of Warrior’s Ridge (White & D'Invilliers 1885). valleys running along Muddy Run (White & Muddy Run lies closest to the Juniata River D’Invilliers 1885). Marcellus shale is (White & D’Invilliers 1885). However, Muddy characterized by black and dark grey colored Run is most likely a tributary of Standing Stone shale (Cooper 1930). The Hamilton Group was Creek. Based on the topographic map of formed during the Middle Devonian period Huntingdon County, the tributaries in the valley (Cooper 1930). The Onondaga Formation is all appear to be flowing from a bend in Standing known for light gray, often semi-crystalline or Stone Creek. Muddy Run is one of many shale-like limestone (Cooper 1930). watersheds in this area. There are approximately Lithologically, the Onondaga Formation is three secondary streams in this valley, including related to the Hamilton Group and was also Muddy Run. formed in the Middle Devonian period (Willard 1936). Finally, the Ridgeley Formation is characterized by thick bedded, coarse sandstone that formed during the Lower Devonian period (Butts 1918). Muddy Run, by the context of its surroundings, formed sometime after the formation of these three geologic formations. Therefore, Muddy Run formed sometime after the Devonian Period, making it younger than approximately 410 million years old. The processes that formed Muddy Run would have formed at a slow rate. A water body close by, Figure 1. Topographic view of the Huntingdon area, highlighting Muddy Run’s location-the sampling area is such as Standing Stone Creek would have circled- between two ridges, and both the Juniata River slowly supplied water to create Muddy Run, and Standing Stone Creek. after each heavy rain event. In addition, the Muddy Run cuts through three geologic incision rate of Muddy Run would have varying formations, the Hamilton Group, the Ridgeley rates depending on the location in question. Formation, and the Onondaga Formation (Figure Facies, joint spacing, migration of knickpoints, 2). The Hamilton Group is made up of the and various other circumstances effect how

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KOPERA quickly each area incises into the bedrock breaking them in half. Therefore, the next step (Whipple & Snyder 2000). was to break apart the sample rocks to examine a clean surface. To identify the rocks, the qualities Based on Muddy Run's topographic location, it of the clean surface were compared to the seems likely that it contains rocks from one or known characteristics of multiple types of all of the geologic formations it cuts through. sedimentary rocks. Finally, the rocks were Muddy Run should contain rocks from an matched to local Pennsylvanian geologic eastern part of these formations, because the formations based on the sample’s lithology. water is moving westward and down gradient. My hypothesis is that the majority of the rocks RESULTS in Muddy Run belong to the Hamilton Group. The rocks observed in Muddy Run appeared to Out of the fifteen rock samples, twelve of the have travelled a short distance, based on their rocks yielded conclusive information (Figure 3). angularity and the general poor sorting of the Three rocks were of a similar lithology. They stream, which made it all the more acceptable to were dark gray, with slight stripes of white hypothesize they would belong to the Hamilton throughout, and were determined to be Group, or one of the other nearby formations. limestone. The nearest formation containing limestone is the Onondaga formation. Therefore, METHODS these samples have possibly travelled a little under 1.6 km to have been deposited in the The observations were focused on the expanse sampling location. Additionally, these rocks of Muddy Run contained in the Juniata College were sub-angular with a low sphericity campus (Figure 2). The experiment called for indicating a short travel distance rocks with no particular characteristics or size, to the keep the sampling group random. Although, for the sake of carrying the samples, most of the rocks fell between 12-30 centimeters long. In addition, any samples smaller than the dimensions mentioned would have been difficult to identify. Much of the stream was covered in ice, which cut down on the possible sampling locations. In total, fifteen rock samples were collected from locations along Muddy Run, the majority of them falling under the coordinates 4029'55.79"N by 7800'43.98"W. The elevation of the site was approximately 650 feet. This area of Muddy Run was characterized by slow moving water and a swamp like environment.

The samples recovered from the stream required extensive cleaning, because thick algae and Figure 3. The top bar graph compares the amount of moss had formed on the bottom of the channel. rocks collected to the identified lithologies: sandstone, The debris, and the fact that these rocks had siltstone, and limestone. The bottom bar graph shows the percentage of samples that belong to each of the been submerged, made it impractical to possible geologic formations in the Huntingdon area. determine the rocks' identities without first

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MUDDY RUN ROCK TYPES

Five rocks were light gray and brown and they intermingled with pale gray or white. The had an indiscernible grain size. These five nearest expanse of Tuscarora Formation is about samples were characterized as Ridgeley eleven kilometers away from Muddy Run and Formation siltstones. Although it was possible the sampling location. The angularity varied that these siltstones were of Brallier origin, the between these rocks samples; one sample was Ridgeley Formation was chosen because it is closer to being sub-rounded, while others geographically closer to the sampling area. appeared to be almost completely angular. These samples could have travelled approximately 1 one km to their final location. Three of the fifteen rocks sampled could not be These samples were slightly less angular than placed back to a formation; therefore, their data the Onondaga samples, and appeared to be sub- was inconclusive. In addition, there is margin of rounded with a higher sphericity. Thus far, all of error in the identification of the classifiable rock samples’ origins were in geologic formations samples, and also in the fact that the rocks were that intersected Muddy Run. collected from only a small portion of Muddy Run.

DISCUSSION

There is geographical evidence that supports the possibility that Muddy Run contains rocks from both the Ridgeley and Onondaga formations. The formations intersect the stream in the east. The rocks eroded from those locations would ultimately flow to the area that was used for sampling. This area of Huntington County is a mountainous region; therefore, the Muddy Run channel could have been a conduit for hyper- Figure 4. KEY: (H): Hamilton Group, (O): Onondaga Formation, (R): Ridgeley Formation. Muddy Run is concentrated debris flows (Baas 2011). Muddy denoted in black. This figure illustrates the geologic Run could have been highly concentrated with formations that surround Muddy Run and Muddy Run’s own location in those formations. Muddy Run is these two formations during the seasonal inside the Hamilton Group, the Onondaga Formation, erosional processes. The area of sampling was and the Ridgeley Formation. downstream from the majority of Muddy Run Four of the fifteen rocks were deemed either and the formation intersections. Stream arkose or quartz types of sandstone. They ranged dynamics is simple; streams scour and fill, from pale white with only a tinge of red, to a aggrade and degrade, bank cut and deposit deep red coloring. The Ridgeley Formation does (Beschetta 1986). Therefore, as long as Muddy not include sandstones with pale to saturated red Run came in contact with the geologic colors. Ridgeley sandstones tended to be tan or formations, it is conceivable that it would gray (Butts 1918). The nearest formation to contain remains of those formations (Figure 4). Muddy Run that contained sandstones with the However, the geography of the area suggests characteristics listed above was the Tuscarora that Muddy Run should contain a part of the Formation. The Tuscarora Formation, known for Hamilton Group, most likely Marcellus shale. its quartzite, formed during the Silurian Period The evidence collected from Muddy Run (Butts 1918). The sandstone of this formation is disproves my hypothesis that Muddy Run would known for the vibrant pink and red colors often

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Figure 5. KEY: (H): Hamilton Group, (O): Onondaga Formation, (T): Tuscarora Formation, (R): Ridgeley Formation. This satellite image shows the geologic formations around Huntingdon, Pennsylvania. The main focus is the fact the Tuscarora formation is geographically far away from Muddy Run. contain rocks from the Hamilton Group. On the Creek. Meandering is common in rivers, and one contrary, there was no evidence of any rocks could have scoured the valley, carried the from the Hamilton Group, despite the stream Tuscarora sandstone, and created Muddy Run. cutting down into the Marcellus shale bedrock. Many of the rocks in Muddy Run are angular and, in general, poorly sorted. This suggests that Moreover, Muddy Run contained rocks from the Muddy Run was at one time moving much faster Tuscarora Formation. Geographically, the to have the capacity to move large pieces of Tuscarora Formation does not touch Muddy Run rock. When fast moving water suddenly loses its (Figure 5). There are many possible hypotheses driving force, a decrease in slope or flow to how Tuscarora Formation rocks may have confinement, the sediment or rocks being carried ended up miles from the original formation. are dropped quickly (Baas 2011). Therefore, it Firstly, although not scientifically backed, the can be speculated that rate of deposition of these Tuscarora sandstones may have been placed in rocks had to have been very fast and had been the sampling location by human activities. associated with a larger water source. Although this can neither be proven nor disproven, Muddy Run is located in an urban There are multiple possibilities to why the rivers area and anyone could have possibly dumped the around Muddy Run moved. A change in Tuscarora rocks into it. morphology could have caused either of the streams to move from Muddy Run’s current A second possibility is that the water source that location (Beschetta 1986). Changes in flow and had deposited the Tuscarora sandstone has long sediment can alter a river’s sinuosity, depth, and since moved. Muddy Run is flanked by two width (Beschetta 1986). In addition, they could rivers, the Juniata River and Standing Stone have moved in accordance to the natural habit of

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MUDDY RUN ROCK TYPES

meandering rivers. Meandering rivers are move more sediment than what is often characterized by the recurrent pattern of the deposited annually (Drexler & Nittrouer 2008). opposing processes of lateral migration and cut- The fast moving water, after slowing down off formations (Parker 1996). Standing Stone would have deposited the sediment and rocks Creek has the sinuosity and other characteristics that had been transported from a higher gradient. of a meandering river. The slowing of the water flow is the main force behind the deposition of high-density flows One could hypothesize that, at one time, (Baas 2011). Muddy Run is located in a valley Standing Stone Creek ran through the valley that and that could be the change in gradient required now houses Muddy Run. Standing Stone Creek to facilitate the deposition of sediment during a could have deposited the Tuscarora sandstone in flood. Again, a multitude of other tests would the sampling area, and then slowly meandered have to be performed to confirm this hypothesis. away. In this case, the rate of formation of Muddy Run would have been slow and the From the observations, one can only conclude mechanism would have been associated with a that Muddy Run contains three distinct meandering river. However, more research lithologies, as well as rocks from three distinct would be required to conclude this possibility as geological groups. Further studies would have to fact. This could be tested by looking at the be carried out to determine the true reason these layers of sediment in the area for signs of rock types were deposited into a small secondary meandering river deposition. stream. However, one can also conclude that the formation of Muddy Run is directly tied to the A third possible hypothesis could be that a mechanism that transported the Tuscarora flooding event moved the Tuscarora sandstone sandstone. into Muddy Run. Exceptional flooding events REFERENCES

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