Elijah J. Chandler

Sept. 8th 2016

Professor Jay

Sedimentary Geology

Mad River Beach- Sediment Differentiation

Introduction

So it all started on August 30th, 2016. I arrived at Mad River Beach in Arcata,

California with my Geology classmates and our professor. We had our supplies and

our assignment and we were ready to go. The weather was cool and windy with an

overcast that lingered above with the chance of rain. Despite the sun being in

slumber on a bed of clouds the scenery was still beautiful. The sand dunes covered

in vegetation gave a surreal feel to the beach which otherwise would have seemed

ordinary. Our mission was clear and concise; we were to form small teams and

transect the location, scouring for information high and low until we came to a

reasonable consensus of data with which we could compare with our hypothesiWe

formed a group to make observations about sediment as it varied across a west-east

transect at the Mad River Beachs. Our west-east transect spanned from the beach

eastward into the fore dune. We formed an hypothesis about what might control the

variation in sediment characteristics across the landscape. Our hypothesis was

simple: Thethat the topography will lead to a differentiation in sand grain physical

attributes in directthat correlates with correlation to theirthe location of their

deposition.

Methods

I was grouped with two fellow aspiring sedimentologists by the names of

formed a group with Chris (last name) and ConnorConner (last name). We began by

creating a conversion of meters to centimeters to use as a scale as we traversed the

landscape. We decided that every 1cm on the map would equate to approximately

12.53m in actual distance. We began at our first station (ground zero) and dug our

fingers into the earth below us, clenching the tiny grains of sand in our fists and with

our free hand we utilized the power of our hand lenses to inspect the particles

which laid idle in our palms. With this hand lens we were able to deduce the

physical components such as color and angularity as well as compositional

components such as feldspar and chert. With our notebook nearby we didn’t leave

the magnitude of our findings in the hands of our memories alone, nay, we wrote

down these details for further inspection and contemplation later.

To ensure clear and concise data we decided to use the table methodWe

formed a table in which to enter our sediment descriptions. Dividing our note space

into columns we created a chart with We used six categories that represented

sphericity, roundness, sorting, color, compositional source, and grain size, and

notesrespectively. On the reverse page we drew slope morphology lines to indicate

any changes of slope and slope breaks as we travelled across the sand, as well as flat

areas to generalize over long distances with little change. We then drew a two-

dimensional representation of the area that correlates with our morphology map to

enhance the understanding of one who is ignorant to the area. Lastly we made sure

to notate the distance we traveled between each station and specified how many

stations there were which ultimately came to 11 areas including group zero. This

took patience and understanding, both of which we maintained throughout the

process.

Results

Discussion

After gathering as much data and information as we could within the

timeframe we were allotted, we began to observe said data and analyze it.Here I

present our interpretations of the data we collected on our west-east transect. We

noticed the difference in paces to each station and took into account that some paces

may have been off due to the steepness of a hill or the obstacles that disrupted our

straight path. However, we noticed that once the data and the slope morphology

lines were set they were as a mirror image to our two dimensional depiction of the

area. Notwithstanding some generalization on the map our data appears to be

complete and is able to tell the story of the distance we travelled as well as the

description of the sediment we encountered while transecting the beach.

During and after our transection survey and after we finished we noticed

some interesting details about the sand grains in different locations. Initially we saw

that between around ground zerostations one through station three the grain size

and sorting was fairly consistentdid not change much and we hypothesized that this

was most likely due to the direct wind and water affecting the area causing

weathering and transport. We then saw that once we were overAt stations east of

the first large dune, at stations four and five, the sediment was fine grained and well

sorted. We hypothesize that this is because the sediment that was no longer

bombarded controlled by the elements in processes that dominated at stations to

the weststations four and five was fine grained and well sorted. As we reached the

steep bottom base of a dune at station 7, we were intrigued bynoticed the dark

sediment surface got darker., which we perceived We hypothesized this to be

influenced by due to the surrounding charcoal., but was in actuality However, our

observations show that the surface of the sand was darker due to darker grains of

sand that retained a larger had a more mafic compositional structure. As we

continued and finished our transection of the beach, into the dunes, these principles

held true and our findings and data reflected this accordinglyour observations

continued to support our hypothesis.

Conclusion

It was a quest for knowledge and inquisition and in the end science and

persistence prevailed. We ended just as we started, cold and expectant. After

walking the distance we gained a broader understanding and appreciation for the

earth around us, as well as the process that is needed to interpret it. From the bus to

the beach and back we used clear methods to accumulate data and draw conclusions

using our intuition and reasoning. Our hypothesis had been correct after all. There

was definitely a differentiation of sand grain based on its location on the beach and

its proximity to the water.

Table 1. Sediment Sample Observations. Then describe the table with words.

Figure 1. Map and Map Scale Calculations. Then describe the figure with

words.

Jason R. Patton, 09/20/16,

Great! Maybe place a north arrow on the map. Others didn’t do this either.