It is the beginning of a solid foundation that I really didn't have to "dig" up.
Cold Spring Trail (the loop)
Length: 1.8 miles For: moderate hikers and those that want an ocean view Rating: 5/5 stars;
My journey in Santa Barbara began as a bright-eyed freshman equipped with black hiking shoes and a massive sunhat. The attractive posters that filled the dorms depicted the hike as a “wondrous” and “beautiful” experience for first-timers in Santa Barbara and I ultimately got suckered in. The drive into the mountains, where the hike to Cold Spring (I still don't understand why there isn't an 's' involved) can be found, was breathtaking. The mountains that peek over Santa Barbara offer a bird’s eye view to the city. After a short uphill trek, the trail offered a little creek and a little further allowed for shade through surplus of trees. Once our group reached one of the top points, the RA allowed us to take a break for lunch. As I searched for the perfect rock to sit on, I started to notice that there was little odd shapes within the bigger rocks. With closer examination, I realized that these were actually some type of fossils trapped within the rocks.
Digging (ha!) even deeper, the fossils became recognizably mollusks (invertebrate that are similar to mussels). However, this made very little sense to me. How exactly did mollusks get into this rock? Taking a step forward, how did the mollusks get into the rocks that are so far from the ocean? Glancing down the mountains, the nearest beach was at least 20 miles downhill. It wasn't possible, nor feasible, that someone collected all these rocks and scattered them all along this trail.
I was confused.
That confusion grew into curiosity and I knew that I needed to figure out how this happened. Taking a couple more pictures and making sure my hiking boots were completely laced before our departure, my burning curiosity had to be put on hold. My RA thought that he was simply giving me a way to bond with other first years in my residential hall. I'm sure he didn't realize that he would be lightening the pathway for my current studies, geology.
After researching deeper into the area, I discovered and fell in love with the densely packed layers of geological history within Santa Barbara. But first, let's build a solid foundation to unpack these layers.
The Basics
I present you quick "Geology 101" blurb (click the geology 101 tab above to find a longer class section) to help those who simply like hike and don't know much about geology. After all, that is exactly how I started.
First, geology involves the studying of the materials, processes and history of that Earth. These materials of the earth include rocks, which is one of my main focuses of this blog. Contrary to popular belief, not all rocks are the same. There are actually three different classes of types. As seen in the picture below, each rock looks pretty different.
Igneous rocks are formed when magma cools and hardens which can happen inside or on the surface of the earth. Sedimentary rocks are formed through a bunch of different particles (like sand, shells, pebbles, broken pieces of other rock types) that end up layering together and eventually over some time harden into rock. Lastly, metamorphic rocks form inside of earth because of a change because of very hot temperatures or extreme pressure. Each of these types of rock has a distinctive a different naming scheme, which I simplify down in the geology 101 tab, in order to keep this blog post more minimal with the basics.
In order to study these rocks and keep everything organized, geologist had to create basic unit called a formation. This unit must be a rock layer that is distinctive enough by appearance to tell it apart from the other rock layers. Some of these rock layers can have a specific name, for example, a strata is a layer of sedimentary rocks or igneous rocks formed at Earth's surface that have consistent characteristics that make it unique. Formations can contain different rock types that are related or can be rocks that are inter-layered together. They can also be grouped together by definable rock strata, which is seen in the picture below.
The right side shows layers of different colors, which can be interpreted as the layering of the rocks. The left shows the layering grouped together by the numbers 1-6, then grouped again with the numbers and a letter. The black bold numbers are groups of formations while the white numbers are the formations.
Another way to think about this classification scheme is kind of like baking cookies, where maybe you are making some peanut butter and chocolate chip cookies for some friends. Some of your friends are vegan, some are gluten free and some have no preferences, which means you have to keep things separate and organized to make sure no one gets hurt. The chocolate chip cookies would be group (formation) 3, with the normal chocolate chip cookies being 3a, the gluten free chocolate chip cookies being 3b and the vegan chocolate chip cookies being 3c. Then, you can do the same thing for the peanut butter cookies, with the cookie type being group (formation) 4, the normal peanut butter cookies being 4a, gluten free being 4b, and vegan being 4c. Then you can label these cookies on plates like this, and voilá, everyone is happy!
Now, that our quick geological lesson is over (remember to take a glance over at geology 101 tab, if you need more guidance and to learn more geological jargon), let's get back to Santa Barbara. It turns out that there are actually numerous different geological formations that can seen while hiking the trails. The Cold Spring Trail will introduce us only to one.
I will primarily be focusing on the rock aspects of The Coldwater Formation, being the geology does encompass a vast majority of information, in this blog post. I will be posting about how exactly the formation ended up in the mountains, plate tectonics, in another blog post in the future.
Let's get started, shall we?
The Coldwater Formation (or The Coldwater Sandstone)
The Coldwater Sandstone, also can be referred to as the Coldwater Formation, is a primary sedimentary rock unit that runs through the southern part of the Santa Ynez mountains in Santa Barbara and eastern Ventura County. It is sandwiched between the Sespe Formation and the Cozy Dell Shale. The thickness of the unit ranges between 0 to 3200 feet that averages at 2700 feet. It was named in roughly 1896 after the Coldwater Canyon that is found north of Filimore, California.
Rock(s) Description(s) ( sedimentary in nature including types of: sandstone, siltstone, shale, mudstone, some conglomerates)
This where the physical appearance pieces of the formation that caught my eye will be turned into geological jargon. All of those physical appearances are capture and turned into something that could be understood and classified scientifically. Who would have known that such natural beauty is actually science!
Arkosic sandstone is the primary geological unit found within the Coldwater Formation. It is a clastic sedimentary rock, meaning that it is primary composed of broken pieces of other rocks or minerals. Arksoic further classifies the sandstone, stating that it carries at least 25% feldspar, a mineral that contains alumina and silica. The sandstone bedding varies from 1 to 150 feet thick. The upper part of the sandstone contains oyster-shell reefs that are stained brown and tend to be harder to touch. The sandstone accounts for 80% of the formation.
I feel like in school we always talk about the variation of animal or plant species on Earth, but I think the overall complete diversity of the Earth is definitely underestimated. In just this area of Santa Barbara, there is a plethora of variation in physical rock appearances that simply blend together to create one formation.
Science really does rock!
Moving forward, the sedimentary rock starts to change into a different form. It becomes a mix of siltstone and shale that are interbedded with the sandstone and tend to be more greenish gray, unless they are weathered to a brownish color. The siltstone and shale are more of a clay texture and are softer in comparison to the sandstone. The siltstone and shale account for 20% of the formation. This bit of information only forces more curiosity in me, like why exactly did the sedimentary rock change form?
Depositional Environment
The depositional environment is a specific type of environment that sediments (aka the rock type for the Coldwater Formation) are created or end up in. It is also where I can get some answers to appease my burning curiosity. Like how did fossils even end up in these rocks?
The Coldwater Sandstone was created by a deposit of igneous rock being washed into sea by streams that drained west. While these rocks were being deposited, the sea was becoming more shallow and slowly diminishing. This is also known as a shallow marine environment. Since waves can vary, sometimes during the deposition, there was times of extreme deep water conditions. These would be the time periods that the siltstones and shales are created. In the later period of the depositions, the coarser sandstone layers and reef fossils are formed due to the depositional environment being extremely close to shore.
And I finally have an answer I was searching for!
During the creation of the upper layer of rocks, they were near a shoreline and thus, when the mollusks started to die, the fossils were trapped into the rocks and ended up in some of the rocks along the Cold Spring Trail. In addition, it also answers my question on why exactly the sedimentary rock changed form. All of this can be accounted for through the depositional environment that it forms in.
I never quite thought about what happens when animals with shells die, since shells do not exactly decompose. By digging deeper into my curiosity, I was given such satisfying conclusion to one of my burning questions.
Rock on!
Trekking Forward
The geological history of Santa Barbara runs deep along a multitude of formations that I knew I had to explore. This was the beginning of my journey and it paved a long road ahead. As an avid hiker with plenty of trails on my belt, I never quite thought about why rocks looked the way that they do or how they formed. With my hair wrapped up in a high pony tail, my backpack fasten and my camera ready, these new insights of geology knowledge can only enhance my hiking experience and hopefully it offers you some new lenses to view the world with.
Stay tuned to uncover more geological history in the layers of our beautiful city.
The Next Hike
The Jesusita Trail ft The Sespe Formation
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