This EarthCache is located within Red Mountain Park, which is currently open daily from 7:00 a.m.- 5:00 p.m. There is no fee to enter the park. Posted parking coordinates are for the main eastern trailhead entrance on Frankfort Drive. To get to the cache location, take the Eureka Mines Trail toward the Red Ore Zip Tour and Hugh Kaul Beanstalk Forest.
The city of Birmingham was founded on June 1, 1871, by the Elyton Land Company whose investors included cotton planters, bankers and railroad entrepreneurs. It sold lots near the planned crossing of the Alabama & Chattanooga and South & North Alabama railroads including land formerly a part of the Benjamin P. Worthington Plantation. The site of the railroad crossing was notable for the nearby deposits of iron ore, coal, and limestone – the three main raw materials used in making steel. Birmingham is the only place worldwide where significant amounts of all three minerals can be found in close proximity. Birmingham soon became known as the "Magic City" as it began its rapid growth in the late 19th and early 20th centuries, becoming the largest city in the state seemingly overnight. The key to this growth was Red Mountain.
As you walk from the parking lot to this point on the trail, you may notice several different types of soil along the path (with starkly differing colors). In fact, Red Mountain is home to a unique combination of geological strata. According to Geology of Alabama (1926):
"At Birmingham the lower 100 feet (30 m) is predominantly shaly and there is a 20-foot (6.1 m) bed of thick-layered sandstone 34 feet (10 m) above the bottom. Above this shaly part lies the Irondale ore bed, which is separated from the Big Seam of iron ore by a few feet of shale and of sandstone layers that carry large and small waterworn pebbles. Next above lies the Big seam, approximately 17 feet (5.2 m) thick, above which these is about 38 feet (12 m) of red sandstone that carries small quartz pebbles, the lower 14 feet (4.3 m) of which has yellow shale about equal in amount to sandstone. About 30 feet (9.1 m) still higher is the Pentamerus-bearing bed (Hickory Nut seam), a ferruginous sandstone full of casts of the interiors of the big brachiopod Pentamerus oblongus. There is still about 70 feet (21 m) more of sandstone, largely reddish, and shale to the top of the Red Mountain formation, making a total thickness in this part of Red Mountain of about 260 feet (79 m).
[...]The most interesting and valuable feature of the Red Mountain formation is its iron ore, which is the chief cornerstone of Alabama's industrial structure. Although ore of good quality and of workable thickness occurs elsewhere, as at Attalla, and on the Red Mountain along the west side of Murphrees Valley, the main deposit, the Big seam, lies under Shades Valley and the part of the Cahaba coal field southeast of that part of Red Mountain which extends from a point a mile or two southwest of Bessemer to Morrow Gap about 8 miles (13 km) northeast of Birmingham.
[...]The Red Mountain ores are known as a red fossil ore, because originally the iron accumulated in extensive beds of fragments of fossils, principally the hard parts of crinoids, bryozoans, and brachiopods. The iron, from solution in some form, was precipitated upon and within these beds of fossil fragments and thus the ore beds are simply a particular kind of sedimentary layers inclosed in ordinary sediments, shales, and sandstones, composing the bulk of the Red Mountain formation. As the fossil fragments were composed of calcium carbonate, which is the mineral that forms limestone, the iron ore beds at depth, where they are unweathered and where there has been no condition that permitted leaching of the lime content, carry a considerable percentage of lime, so that the ore is self-fluxing. Another type of ore is oolite ore, in which the iron oxide occurs in the form of small lenticular pellets. The precipitation of the iron that forms this ore started around some minute particle like a small grain of sand or fragment of fossil and built up a small lenticular body. The two kinds of ore are more or less mixed or one or the other may predominate in a particular layer of ore."
From this point on the trail you will not only observe several large reddish sandstone blocks, but as you continue to ascend the trail from here you will observe that the fine red rust from the iron ore coats even the tree roots, giving them an almost otherworldly, purplish-red hue.
As steel furnaces modernized, labor cost rose, and geological faults in the local ore mines made the ore harder to reach, it became more economical to purchase pelletized ore from distant sources than to continue mining ore from Red Mountain. The last ore mine on Red Mountain closed in 1962 and was operated by US Steel. The last ore mine in the Birmingham district closed in 1972. Now, Red Mountain is home to the newly created Red Mountain Park, one of the nation's largest urban parks at 1,108 acres, making it larger than even New York City's Central Park.
To log this earthcache, you must answer the following questions from your observations and the information I have provided. Send them to me via my email address on my profile. Do not post them to your log or it will be deleted.
1. Describe the changes in soil that you observe as you travel from the parking area to GZ. What do you think accounts for these changes?
2. What makes the red color that characterizes Red Mountain?
3. There are a number of rectangular sandstone blocks in the area of GZ. Do you think that these rocks naturally broke into these shapes, or that they were cut this way?
4. What is a brachiopod? What part did crinoids, bryozoans, and brachiopods play in the formation and deposit of Red Mountain sediment?
5. (Optional) Take a photo of yourself (or your GPS) at GZ to verify that you visited this site. I hope you enjoyed your trip to Red Mountain today!
If you enjoyed this cache, please give it a Favorite ribbon!