Weathering and Erosion in Estes Park

     Weathering, also known as rock decay or stone decay, is the breaking down of rocks while they sit in one place. Erosion is the transport of the weathered material. Weathering starts with joints which are cracks that weaken the rock. The joints make it easier for the rocks to break down physically or chemically. One of the physical rock decay processes we see in Estes Park is frost decay or frost wedging. Frost wedging is common on mountaintops above the treeline. Frost wedging is the freezing and thawing of water in joints. As water freezes in the cracks, it expands which creates force that makes the rock split apart. Another physical decay process we can see in Estes Park is root wedging. The roots of plants can spread into cracks and force the cracks to expand. In some areas, we can also see domes that have been created by pressure release. When a large rock forms under great pressure, erosion causes slabs of pressure release shells to pop off of the rock. The rock becomes rounded over time when multiple pressure release shells pop off.

The joints make it easier for weathering to take place. In this image we can see root wedging. Seeds get into the joints and grow after they absorb nutrients from the rock particles and water.

Trees can't grow above the tree line because the temperatures aren't suitable. Frost wedging takes place above the tree line. This is Longs Peak in July of 2014 and in April of 2013.

The edges on the rounded rock show where pressure release shells popped off.

      Biological weathering processes can be seen in Estes Park. When living organisms contribute to the decay of rock, it is considered biological weathering. Lichens are a combination of algae and fungi and they are common in Estes Park. Lichens take minerals from the rocks through ion exchange. The wetting and drying of lichens can cause them to expand and contract. Lichens weather rocks chemically by releasing acids. The loss of minerals through ion exchange, the expansion and contraction, and the production of acids can weaken rock and make pieces flake off.

 The light green and orange substances on the rock are lichens.

Sources:

All photos in this post were taken by me, Sylvia Jackson.

Dr. Casey Allen's lecture “Rock Decay”

McKnight's Physical Geography: A Landscape Appreciation, Edition Eleven by Darrel Hess

http://www.earthonlinemedia.com/ebooks/tpe_3e/mass_movement_weathering/physical_weathering.html

What Geography is and Rocks in Estes Park

What Geography is:

     Before I write about the physical geography of Estes Park, I would like to write about the definition of geography itself. A lot of people, including myself, learned in middle school that geography is about maps and sometimes landforms. Though geography does include those things, it is so much more than that. The basic definition of geography is, “The location and distribution of features at/near the Earth's surface.” The elements of geography can be grouped into two categories, which are physical geography and cultural geography. Cultural geography focuses more on people and contains elements such as population, economic activities, languages, religions, political systems, settlements, and food. I will mostly be focusing on physical geography which contains elements such as landforms, rocks and minerals, water, weather and climate, plants, animals, and soil.  

Rocks in Estes Park:

     There are three basic rock types which are Igneous, Sedimentary, and Metamorphic. 

A canyon wall in Estes Park.

Rock formations such as the one above can be seen in and surrounding Estes Park. The rock formations have characteristics of sedimentary rocks. Sedimentary rocks are made of layers known as strata.

Over time and during major events like mudslides, earthquakes, and floods, sediment can accumulate in one place. As more time passes, more sediment will accumulate, creating another layer.  

A closer view of the mountain that is next to Lake Estes.

Sedimentary rocks can be formed in many different ways. There are different classifications of sediment and they are Clastic, Chemical, and Biological. Clastic sedimentary rocks are distinguished by size and are formed by fragments of preexisting rocks. Depending on the size, the rock could be classified as Shale, Siltstone, Sandstone, or Conglomerate. Chemical sedimentary rocks are formed by the evaporation of water or precipitation of solids from ions in a solution. Biologic sedimentary rocks are formed by the precipitation or accumulation of organic material such as plants, shells, or skeletons.

If we take a closer look at the canyon wall in Estes Park, the size of the particles vary but are mostly consistent with sandstone and siltstone. The sedimentary rocks in Estes Park could be formed in many different ways, but over time they can be heavily effected my weathering and erosion.

Sources:

All photos in this blog post were taken by me, Sylvia Jackson.

Dr. Casey Allen's lecture “What Geography is... and Earth in Space & Place”

Dr. Casey Allen's lecture “Earth's Innards (Basic Rock Types)”

McKnight's Physical Geography: A Landscape Appreciation, Edition Eleven by Darrel Hess

http://www.physicalgeography.net/fundamentals/10f.html

Introduction

     My name is Sylvia Jackson. I have chosen to write about Estes Park Colorado. I have chosen this location because I am familiar with it, it is close enough that I can go to the location and study it, and I think it could be an interesting place to research. It is my favorite place and I go there at least twice a year. I will be talking mostly about the physical geography of Estes Park, however, I would like to briefly write about the history of Estes Park.

     There is evidence that humans have lived in the area for at least 12,000 years. A Paleo-Indian culture known as the McKean people moved into the area around 2000 B.C. About 10,000 years ago, the Ute and Arapaho tribes spent their summers in the Estes Park valley. Joel Estes later discovered the valley while looking for gold. Estes Park became popular after Griff Evans bought the land and built a dude ranch. Recently, Estes Park has been through natural disasters such as forest fires and floods. I am excited to see what other events occurred in the past that made it into the location we know today. 

Photo of  Lake Estes by Jamie Palmesano

http://www.city-data.com/picfilesc/picc13792.php

Sources:

http://www.visitestespark.com/maps-and-info/about/history/