Hodges Gardens' Tree of Stone EarthCache
Hodges Gardens' Tree of Stone
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The location of this Earthcache is within Hodges Gardens State Park. Hours of operation are from 9am – 7pm daily. An entrance fee of $5 per person ($4 seniors, 62 years and up), or a valid Louisiana State Parks Pass, is required for entry.
Introduction
This Earthcache briefly explores the process of petrification by visiting a beautiful fossilized member of a now extinct tropical forest. Petrified logs such as this and smaller pieces of petrified wood are somewhat common throughout the West Louisiana and East Texas region. In fact, you are likely to run across several other examples while visiting this park. Most are associated with Miocene aged strata which date from between 5 and 25 million years ago.
The Process of Petrification
The petrified log you are looking at was once a tree that stood in a tropical forest many millions of years ago. After the tree fell it was quickly buried by mud and sediments which preserved and protected it from the elements, bacteria and other forces that cause weathering and decay. Mineral rich water permeated the sediments and wood and began to deposit silicon in the tree’s cells. As the tree’s organic matter was slowly broken down, and as more and more silicon was deposited, a stone mould of the tree was created. So the log you see here today is not the actual tree but rather an exact silicon copy. The varying hues of color in the petrified log are a result of elements that contaminated the quartz as it was being deposited. A list of some of those contaminating elements and the colors that result when they’re present can be found below. Some of the listed colors you will see in this petrified log, others you will not.
- carbon - black
- cobalt - green/blue
- chromium - green/blue
- copper - green/blue
- iron oxides - red, brown, and yellow
- manganese - pink/orange
- manganese oxides - black
To Log this Earthcache:
To claim your visit to this Earthcache site, please complete and submit answers to the following four questions prior to logging your visit. Answers can be emailed to me at broken.trowel@gmail.com. Please, do not post answers in your online log. You do not need to wait for a confirmation to log the Earthcache, however, failure to provide the required info will result in your log being deleted.
- How long would you estimate this petrified log to be?
- What would you estimate the diameter of this log to be near its widest part?
- Inspect the log looking at all the different colors present in the petrified wood and refer to the list of contaminating elements above. List at least three of the colors you see and tell me what contaminating element likely caused that color.
- From the nearby sign, what is the name and location of the laboratory that has not been able to identify this species of tree?
I hope you enjoyed your visit to this, West Louisiana’s first Earthcache site! Permission for the placement of this Earthcache was granted by Kim Kelly, Manager, Hodges Gardens State Park, 1000 Hodges Loop, Florien, LA 71429
References:
- Busbey III, A. B. , R. Coenraads, D. Roots and P. Willis. 1996. The Nature Company Guides: Rocks and Fossils. Time-Life Books: Singapore. 288 pp.
- Heinrich, P.V. 2001. Louisiana Petrified Wood. Online.
- How Stuff Works? Date unknown. What is a fossil? Online.
- Moody, R. The Fossil World. 1977. Chartwell: Secaucus, NJ. 124 pp.
- Wikipedia. Date unknown. Petrified Wood. Online.
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