Great Smoky Mountains National Park

Location: On the border between Tennessee and North Carolina containing portions of the counties of Swain and Haywood in North Carolina and Sevier, Blount, and Cocke in Tennessee.

Introduction:

Great Smoky Mountains National Park (Smokies for simplicities sake) (Wikipedia page) is actually a park that I have been to several times before but most of these times were before I had started blogging at all. It had been a while since I had done anything outdoorsy let along go to a National Park it was nice when my wife and I were able to get away for a weekend and head out there. While it is still too long a drive for us to justify heading out there every weekend if you live in the Knoxville area it is ~1 hour away and totally worth many trips.

The Smokies is a huge park encompassing over 500,000 acres total between Tennessee and North Carolina. What makes it more impressive is on several sides are National Forests making the natural beauty of the area seem to go on forever. The towns around the area are very cliche and touristy but this means the type of people you will meet in this park varies drastically from who you will meet in other parks. In fact the Smokies were the 3rd most visited park in 2011 with over 9 million visitors. This isn't always a good thing for someone who enjoys getting away from it all as there are people who head to this park that likely haven't been or won't be headed to any other park so typical park/hiking etiquette is often thrown out the window, along with garbage sometimes I am afraid. This isn't the fault of anyone who works at the park but its location is part of the problem. As I mentioned it is only an hour from Knoxville but it is within driving distance for many other major cities in the Eastern United States, such as Atlanta, GA. It is also free to get in, minus any charge for camping if you do that or hotel if you don't.

With all of that said if you live nearby and haven't checked out the Smokies yet you need to. There is a natural beauty to the park that is not seen in many of the big cities on the east coast. Trees, including old growth forest, abound and animal life from the common white tailed deer to the less common black bear are very often seen but perhaps most impressively and only rarely seen are the Elk which were reintroduced to the park in 2001, I have never actually seen elk (although I am pretty sure I saw evidence of them this past trip, even if it is an area where they aren't known to be so I could obviously be wrong and it could just be evidence of a large deer). Much of the local plant life is on display as well and during the spring there is a rush of people coming in to photograph the wildflowers, they were just starting to open up when we were there, and in the fall there is just as big a rush to take pictures of the beautiful fall leaves that makes the area many brilliant colors. I have been in both the summer and winter as well, and trust me both those times are absolutely beautiful as well.

Heavy visitation and being near so many urban areas has also effected several other aspects of the Smokies. While it gets it's name from the fog and low clouds that sometimes cover the area air pollution has been causing problems from as simple as making views appear hazy to as dramatic as killing plants due to the effects of acid rain. Another major problem has been the infestation of an insect called the hemlock woolly adelgid. This insect infects hemlock trees and basically sucks them dry causing them to die off, you can see evidence of this throughout the park, both dead and infected trees abound, and like the American Chestnut in the '20s and '30s the hemlock is likely to be extinct in the region soon if the National Park Service can't get it under control. That doesn't mean they aren't trying to stop the spread of this insect but they may already be fighting a losing battle.

All the problems you would expect with a major tourist destination aside, yes that includes traffic jams, the park is big enough and there are enough areas that are not visited much that it is easy to find yourself in the peace and serenity of nature. I will be headed back soon and every visit I find something new. The area is beautiful and even if you don't want to see nature you can see buildings built when the area was still the frontier or you can just be a tourist and stay in the towns around the area and just go check out the visitor center there are many different options.

Geology:

Interestingly enough the geology of the Smokies gives me a great place to pick up from Russell Cave NM and C&CNMP as far as the geology of the southeast is concerned. It is worth going to check those two out because the rest of this post is going to be based on the assumption that you already at least partially understand what is going on there.

Looking at the regional geologic map, which can be downloaded or opened here (you will have to click on the link for the huge PDF), it should become obvious that the area has two primary geologic rock types. To the north and west there are primarily sedimentary rocks, these rocks are similar, although not quite the same aged as those at RCNM and C&CNMP. These sedimentary rocks represent the Ridge and Valley Province and were likely laid down in conditions similar to those of a warm shallow sea. To the south and east the rocks contain a mix of igneous and metamorphic with metamorphic rocks being the primary constituent. These rocks represent the next geologic province the Blue Ridge Province (also known as the Blue Ridge Mountains). The contact between these two provinces can vary from place to place, in some areas of the east the sedimentary rocks of the Ridge and Valley slowly become more and more metamorphic till they are the very metamorphic rocks of the Blue Ridge while in other areas the transition is very abrupt.

Moving on to the more local map, found here (warning link goes to PDF), you can see that the majority of the park consist of metamorphic rocks, meaning that the Smokies are located in the Blue Ridge. So lets talk on a very short description of how the Blue Ridge formed. Very simply the Blue Ridge was formed by accretionary metamorphism. During the formation of Pangaea as well as the formation of the previous super continent Rodinia, during the Precambrian more specifically the Mesoproterozoic the east coast of the US moved eastward. During this time subduction of an oceanic plate was occurring under the continent, this produced a lot of heat (this is why there are currently volcanoes on the West Coast and why there are igneous rock on the east coast (and even this comes with a caveat that it isn't a Triassic/Jurassic rift basin)) and pressure. This heat and pressure caused changes in the rocks in what is now the Blue Ridge and Piedmont changing them from sedimentary to metamorphic rocks and why in some areas the transition is very hard to see. In the Ridge and Valley this accretion caused the many different anticlines and synclines you see but similar things happened in the Blue Ridge some fell over or got pushed over the younger sedimentary rocks to the west, this will be important in a minute.

During the Mesozoic the Appalachian Mountains, of which the Blue Ridge is a part, may have been as tall as the Rockies are currently but as accretion/subduction stopped so did the mountain building and eventually the only force acting on the mountains was erosion. As the Appalachian got more and more rounded off and lower in elevation due to erosion all of this rock material flooded the continental shelf. This caused loading on the shelf which lifted up the continent and again raised the mountains. There are some ideas why you can have the same rocks in the Piedmont and Blue Ridge but a huge elevation change is due to the a fault or some other geologic feature being able to act on the western side and force up the Blue Ridge while other ideas say that the Piedmont has just been eroded away. All of this relates to the uplift currently of both the Blue Ridge and the Ridge and Valley, which allows rivers like the New River to form great cuts in locations.

During all of this time the rocks on the Blue Ridge that had been pushed on top of the younger sedimentary rocks in portions of the Smokies were being eroded away as well. In several areas these rocks completely eroded away to expose the underlying sedimentary rocks in what is known as a tectonic windows. This is why on the geologic map you may have areas of old, non alluvium, sedimentary rock surrounded on all sides by metamorphic rock. The most famous example of this, also one of the most visited (I am sure most of the people who visit it don't even realize what they are driving through), is Cades Cove in which the ~9 mile driving/biking route follows most of the outer edge of the window.

That is a very short summary of the geology but as it is getting long already I will call it quits. As should be obvious from this is just how complicated the geology that formed the Smokies, and much of the east coast in general, actually is.

More Pictures: All images are by the author ask permission if you want to use them, and if you do make sure you give me credit.

Further Reading:
Southworth, S., A. Schultz, and D. Denenny. 2005. Geologic map of the Great Smoky Mountains National Park Region, Tennessee and North Carolina. U.S. Geological Survey Open-File Report 2005-1225. (Link goes to PDF)

Thornberry-Ehrlich, T. 2008. Great Smoky Mountains National Park Geologic Resource Evaluation Report. Natural Resource Report NPS/NRPC/GRD/NRR—2008/048. National Park Service, Denver, Colorado. (Link goes to PDF)

NPS website on the geology of the Smokies.

National Park Service Series Page

Chickamauga and Chattanooga National Military Park

Location: Northwestern Georgia near the border with Tennessee and Alabama in portions of the counties of Catoosa, Dade, and Walker as well as in Southeastern Tennessee in and around the city of Chattanooga in Hamilton County.

Introduction:
On the same trip that my wife and I went to Russell Cave National Monument we also hit up Chickamauga and Chattanooga National Military Park (Wikipedia page), since we were going down to the Chattanooga area anyway. This park is actually consists of a grouping of several parks that are in close proximity so they all fall under one name. The reason for this is that the city of Chattanooga had taken over many of the locations used in the battle after the Civil War ended so the NPS had to purchase some of the land piecemeal as well as having several things within the city itself. Another reason why it is multiple pieces of land is that there are in fact 2 main battles that took place in this area, one would eventually lead to the other but there is a gap in time in between.

I grew up as a history buff and one of the most interesting times to me was the American Civil War. As such I have been to many of the battle sites and I have always enjoyed them as they are always interesting and try to show you the scale, not only geographically but of human loss, that each site exhibits. I have been to where the war started, Fort Sumter, where the war ended, Appomattox Court House (sorry about that not linking to a post this was before I started blogging), and many places in between, including Gettysburg and many of the sites in Northern Virginia (again sorry for not having a post but those trips were also before I started blogging). Each battle has its own story and at everyone the NPS staff works to let you know not only how the battle fit into the overall story, but also how the battle fits in to the stories of individual from the war, and we aren't just talking General here but everyone down to the lowly privates.

Growing up and spending a lot of my time in the east it is easy to forget how major many of the battles of the west were. The east is where the show was, the west was how the North won the war. By the September of 1863 the Confederates were in trouble and they were starting to feel it. By this time the Battle of Gettysburg had happened and the Union had won not only there but in Vicksburg and now controlled the entire Mississippi River. The South was feeling the choke of the Union blockade and knew something had to be done. The North leading up to these battles had almost taken all of Tennessee and the marches leading to this battle would allow a Union capture of Chattanooga.

The Battle of Chickamauga would represent a slight turn for the Confederates. Union forces held the high ground and the ground easiest to defend by the start of the second day of the battle. Some costly maneuvers due to some poorly written/poorly understood orders would lead the a Union retreat that was averted total disaster by Union forces capturing the highest ground around an almost cliff like climb for the Confederates brought an end to fighting. By the next morning the Union troops had fallen back to the city of Chattanooga itself.

The city of Chattanooga sits at a bend in the Tennessee River and is surrounded to the south and east by high ridges. The Union stayed in the city which allowed the Confederates to put their guns in a position to fire heavily into the city. But the Union over the long run had more men and better weaponry. Eventually a commanding officer would be put in place who could handle the situation. The Union forced open a supply line which brought in fresh troops and supplies so that by the end of November the Union forces would be able to take back the hills around the city. The attack began on what is known as Lookout Mountain and eventually Union forces climbed to the top to find that the Confederates who had started the day shooting at them had abandoned their positions. The Union victory and ability to hold Chattanooga would allow General Sherman to have a supply base on his march to Atlanta and eventually to the sea.

I have been to several different types of Civil War sites and this one had a uniqueness of its own. Civil War sites in cities, like Petersburg, often feel cramped in or at least surrounded while those out in the country, like Appomattox Court House, often feel like they take forever to get to. This site has a little bit of both. You feel a little ways away from the hustle of the city while not actually being that far. I enjoyed the trip and recommend anyone in the area to head down and check it out.

Geology:

I don't want to repeat myself too much here so I recommend you go check out my post on Russell Cave National Monument as these two sites are only about 30 minutes away from each other so the overall geology isn't that different. What I want to stress here is just how important geology is to wars, especially the Civil War, and I can assure you I can think of several more sites where geology plays a major role in the way the battle was won/lost. While the actual knowledge of geology was not important for the battle the way the battle took place could only have occurred because of the set up of the geology in the area.

The Battle of Chickamauga was takes place in an area of low rolling hills with some areas of higher relief. The rocks in the area where the battle took place represent what is known as the Ridge and Valley Province. These rocks have been heavily uplifted as well as folded and faulted. There are also a lot of limestone in the area and this is easily eroded away to produce sinkholes or just lower areas where rivers and streams flow. At the end of the first day and beginning of the second day the Union forces held a line on a slight limestone ridge, they owed this ridge due to erosional factors that had lowered the surrounding area while the ground sloped more gently behind them. This gentle slope led the the next formation above/younger than the one they were on. While the eventual falling apart of the Union line had little to do with geology their survival is directly because of it. Where the younger higher formation has a lot more limestone in it, this means it erodes faster, this quicker erosion can cause steeper cliffs to form since the erosion is going to be faster at the edge and with a more easily eroded formation the erosion will likely start from the edge, since that is where the rock is exposed. As the Union forces retreated they regrouped up on top of a short steep ridge. This was enough for them to gain an area where they had the firing advantage and were able to hold off the Confederates long enough to form a more cohesive retreat.

The Battle of Chattanooga is a different story though. The high ground around the city of Chattanooga is due to the ridges being caped by a layer of sandstone and/or conglomerate. These rock types are harder to erode and as such will stand up longer to erosional forces than will other rock types. The city itself sits primarily on the flood plain for the Tennessee River. These river sediments buried arrowheads and other archeological remains so that they could be found in what is now another part of the Chickamauga and Chattanooga National Military Park, in what is known as Moccasin Bend, we did not get a chance to go here however (mostly because most of it is closed off to the public). These ridges gave the Confederates a better firing angle on the city but they did not use them well enough as supply lines were eventually opened. Under the sandstone layer are more layers of limestone this is why the sandstone in this location is interpreted as a river setting that temporary buried a calcite producing system, if you want to know how look at how far the plume of debris from the Mississippi River goes out into the Gulf of Mexico today. The lower layers being limestone creates really steep cliffs on the sides of the ridges and these steep cliffs make it hard to get to the top but as you are shooting down they make it hard to shoot at the people directly below you as well. This is what would eventually force the Confederates off the ridges around the city and would allow the Union to win the battle.

More Pictures: All images are by the author ask permission if you want to use them, and if you do make sure you give me credit.

Further Reading:
University of Tennessee Chattanooga (UTC) site on the outcrops of the area.
Another piece by UTC on the geology visible from Lookout Mountain. (PDF)
If you want to learn more about the history of the site visit the NPS page.

National Park Service Series Page

Russell Cave National Monument

Location: Jackson County in the Northeast corner of Alabama near the border with Tennessee and Georgia.

Introduction:
As my wife and I are trying to complete our tours of National Park Service operated properties we sometimes have to go off the beaten path to find them, Big Bend while large and famous park is just one example, we have hit several others in the past, before I started blogging hence why they aren't on here, as well though. I like visiting the smaller and/or less visited parks because it is easy to say to brag about the random ones you get, but I also would like to see some of these parks get more visits so I want to make sure that I get to blogging about them. We came across Russell Cave National Monument while on a trip from Nashville to Chattanooga (note there was another park visited in the process so expect another post soon) and we noticed it on the NPS find a park map so we figured we pretty much had to hit it up.

Russell Cave National Monument (Wikipedia page) is one of the smaller parks I have ever visited but if anything that adds to its flair. Driving through back roads in northern Alabama has never been on a wish list of mine, note I'm not saying I have a problem with it just never saw myself doing it, but to get to the park you need to do this. When we arrived on the warm early October day (yes I have been sitting on this post for a while so what) we ate lunch in the nice little picnic area in the front of the park. It was a weekday so they didn't have any events going on, they do on some weekends, so we got a personal tour of the visitor center which is always nice and had a great experience.

Geographically Russell Cave is in the southern Appalachian Mountains and sits in a valley just a short distance from the Tennessee River. The trail system is not extensive, there are only 2 and they both branch off the same base trail, but they allow you to see the "cave" as well as other geographic formations typical of Karst systems, such as a major sinkhole. The main trail that goes to the cave is on a boardwalk so is very accessible to anyone from those in wheelchairs to those with strollers and overall the park is a good stop for people traveling through the region to stop and eat a picnic lunch and to stretch their legs, just remember to sign the guestbook inside the visitor center if you do stop.

Visitors to Russell Cave are no longer able to go very deep into the cave, I would guess for safety reasons since it wasn't a very developed cave, but there is a little overhang area where there are displays. The actual portion of the cave that, according to our guide, they used to allow people to go into has a river flowing into it that you can actually see flow from under a rock wall near where the sinkhole is. The cave has a long history with humans where it served as a likely home to humans for at least 8,000 years. This is actually why the Russell Cave is a national monument. During the 50s the cave was the site of excavations by the Smithsonian and National Geographic, there were a couple of papers published on it and Nat Geo published an article titled Life 8,000 years ago uncovered in an Alabama cave (I can't find a spot to link for it online so if someone knows where I can find it let me know in the comments), I will talk more about the archeological excavations in the geology section. A short time later the National Geographic Society, who owned the land at the time, donated the land to the NPS which allowed for the creation of Russell Cave National Monument.

Geology:
During the Mississippian much of the western portion of the current Appalachian Mountains was under, or near a, shallow warm ocean. The Mississippian, for those who might not know, is part of the Carboniferous which is named for the large number of coal formations from around the world. In the Russell Cave area the sea was shallow and warm which allowed for a large limestone deposit to form. It is likely that there are many reef building organisms preserved in the formation but I didn't get close enough to the rocks to actually get a chance to look. As I have explained in the past (see here and here), limestone is dissolved away by water that is slightly acidified by CO2. Since I have explained this in the past I wont say anything more here.

The current Appalachian Mountains have slowly been being uplifted further and further west as time as gone on. This uplift is caused by an isostatic response caused by sediment from the eroding mountains being loaded onto the edge of the continent. As the mountains are uplifted the rivers that flow through the region cut down through the rocks, this is why there are large valleys along the New River in West Virginia, as they try to stay at base level. In the area near Russell Cave the Tennessee River has been working hard to cut down through the rocks and it is likely either the river itself or one of its tributaries cut down to the rocks and exposed Russell Cave.

We know that there were humans in North America by at least 10,000 years ago. Humans like to use premade shelters for safety etc and sometime around 8,000 years ago we know humans first appeared in Russell Cave. Humans were able to use the cave because the roof fell in, due to the typical karst processes, and a build up of sediment around the portions of the roof that fell in. This sediment made a dry area above what would have been a typical flood level, although large flood would likely have still covered the area. The sediment trapped evidence of the humans who used the cave including arrowheads, fish hooks, and bones of killed animals. The excavations have found influence of multiple cultures through time but there is little current excavation, that I know of at least, so there may even be some evidence of earlier times. I would not be surprised if under the level last excavated even if there aren't humans it is likely that there will be some fossilized animal remains but I can't know for sure without further excavations.

More Pictures: All photos in this post were taken by the author ask for permission if you want to use any of them.


Looking into the cave.



One of the displays in the cave.



The creek that formed the cave coming out of the rock wall right nearby that has a sinkhole on the otherside.


Further Reading:

Miller, C.F., 1956. Life 8,000 years ago uncovered in an Alabama cave. National Geographic Magazine. (Seriously someone find this for me please)

National Park Service Series homepage

Big Bend National Park

Location: Western Texas in Southernmost Brewster County along the border with Mexico.

Introduction:
I have been wanting to do a post on Big Bend for a long time, mainly because most of my fellow paleontology graduate students were doing work on material from here, but I couldn't put a post together till I had been there [Image at top looking out the Window in the Chisos by author]. Finally as I was getting ready to leave Lubbock I convinced one of the other students to drive out there with me for a couple of days so I can now say I have been even if we played tourist at the end of July and were trying not to melt the whole time we were there (note: it is hot in the desert in July).

Big Bend National Park (Wikipedia page) is not a national park that you just happen upon you have to make the conscious effort to get there. The fact is even the county it is in is off most peoples beaten path, there are no interstates that go through the county, and with a population of ~10,000 people very few people will ever visit the area. Big Bend is also in the middle of a desert which most people tend to avoid, especially during the hot summers which also happen to be when most tourists visit the other national parks. All of these reasons make Big Bend one of the least visited of the parks in the NPS system.

I mentioned that Big Bend is in the desert and it is part of the Chihuahuan Desert this desert extends up into New Mexico in fact 2 previous national park series posts, Guadalupe Mountains and Carlsbad, have talked about parks in this desert. Now this is not the desert that most people picture when they think desert, there are no big cacti and tons of sand. What there is instead is a very dry environment with for the most part low growing plants that have adapted to be able to live with little to no water for extended periods of time and when they do get water they make the most of it. There is plenty of mesquite as well with its long roots that reach deep for water and can find water in even the driest of environments. But there is more than just desert as the park varies from 1800 feet up to over 7000 feet there is a wide range of climatic differences. The Rio Grande and its flood plain make of a rich fertile wet soil that keeps plants growing almost year round and in the valley actually makes it quite humid. The desert has two ranges one the high desert and the other the low desert both have unique and varying vegetation types. And finally the Chisos Mountains that extend from the desert floor reaching up to the sky, the basin in them where the campsites are is over a mile high, the micro-climate here is cooler, I woke up in the morning actually cold and wanted to put on a long sleeve shirt, and more wet than the surrounding area and is the only place in the park where true trees can and do grow, also home to bears and mountain lions.

Ok I have rambled on long enough with the intro but lets just say if you happen to be nearby for whatever reason go visit Big Bend it is worth your time.

Geology:
This park is so large (~800,000 acres) and has such a vast diverse geologic history that this is really only going to be an extremely brief summary of the geology of the park because I could ramble on for a long time about it [Image at left of Santa Elena Canyon by author].

In the Triassic while Pangaea was still around this area of the country was exposed to the surface so unlike good chunks of the rest of the state there are no Triassic rocks in Big Bend. During the Triassic and Jurassic, however, Pangaea began to break apart this caused many of the rift valleys on the east coast of the United States and slowly started to allow for subsidence of the middle portion of the country. By the Cretaceous a large body of salt water that connected the still forming Gulf of Mexico to the Arctic Ocean, this was known as the Western Interior Seaway. This seaway was shallow and warm which is the perfect conditions for calcium carbonate secreting organisms to live in and these organisms form limestone deposits, see Guads, Carlsbad, and Mammoth Cave posts. These limestone deposits form the famous Glen Rose Formation in most of Texas along with most of the other limestone formations in the center of the state, they also form the limestone and chalk formations up into Kansas where the less famous, but equally important, Niobrara Chalk is. In the park there are thin bands of the Glen Rose but the most obvious example of this limestone is the massive limestone cut by the Rio Grande to form Santa Elena Canyon.

Late in the Cretaceous the sea level fell and the Western Interior Seaway began to recede toward the Gulf of Mexico, in the U.S. at least. As the sea level dropped river systems began to flow through the region and toward the very end of the Cretaceous portions of the park where underwater and portions where on land. During this time many dinosaurs lived in the area and in the formations that represent this time we find their fossils. The dinosaurs weren't alone during this time as the pterosaurs had grown to their largest size yet and Big Bend represents the type location of one of the largest the ~10 meter wing spanned Quetzalcoatlus northropi (Wikipedia page). The actual contact that represents the end of the dinosaurs, that famous iridium layer, is not found in the park although it should be no one has found the contact yet, although we are still looking.

Whatever happened to the contact the area continued on being a warm wet swampy habitat through a good portion of the Eocene, fossils from the mammals that lived at this time can be seen at a roadside stop known as the Fossil Bone Exhibit in the park [photo at right of the Eocene sedimentary rocks near the fossil bone exhibit by author]. These animals were sitting on a ticking time bomb, however, because while they were living here under their feet were building up massive igneous intrusions.

These igneous rocks would eventually burst through eventually and would form the Chisos Mountains. There were likely at least 3 major events of eruption and evidence throughout the park is obvious. In an area known as Tuff Canyon, tuff is a type of volcanic ash, there are ash rocks that have been heavily cut by water but in the ash layers there are evidence of lahars and lava bombs. Eventually the composition of the magma changed and it came out more runny this formed areas where you have lava being deposited on top of ash and they are exposed for many meters in elevation. The igneous rocks shaped the park and through the area there is evidence of volcanics but also plenty of evidence of intrusives as igneous dikes cross roads in several places.

Volcanism eventually stopped and the area settled tectonically but it wasn't quite done yet. As with the Guads there was at least one period of uplift formed as the western edge of the Basin and Range that uplifted many of the rocks and with the help of erosion giving us the geography we have now. The park has obviously also become a desert and this likely occurred closer to the end of the last ice age as climates every fluxed due to the change in flow patterns caused by the loss of the glaciers.

More Pictures: I have even more pictures in the Big Bend portion of my Flickr page, all photos by author.


More "runny" volcanic rocks on top of an ash layer.


Cretaceous aged sedimentary rocks


Roadrunner


Welcome to Big Bend National Park

Further Reading:

The NPS pages on the Geology of Big Bend and the Fossils of Big Bend, as well as all the links included in the fossil page.

Long and very technical USGS Circular 1327: Geological, Geochemical, and Geophysical Studies by the U.S. Geological Survey in Big Bend National Park, Texas from 2008, from that link you can download the whole thing.

See many of the papers by Dr. Tom Lehman at Texas Tech University, and if you walk through the second floor of the building near his office you will see other posters and papers of his and his students research.

National Park Service Series homepage

Mammoth Cave National Park

Location: North-central Kentucky in portions of Edmonson, Hart, and Barren counties.

Introduction:
I was originally going to hold this post off till later but in honor of Earth Day and National Park week, many parks will allow you in for free or cheap through Sunday (April 24, 2011), I figured I would get this post done early.

Spring Break 2011 brought me to Nashville, TN and while Tennessee itself is home to many national parks this is the closest one to Nashville. About an hour and a half to two hour long drive from Nashville, Mammoth Cave is also close to other metropolitan areas such as Louisville, KY. Mammoth Cave (Wikipedia page) was the second of the cave systems within the National Parks that I visited, the first was Carlsbad Caverns National Park. Mammoth Cave National Park covers a large area and includes many different areas to hike around outside and enjoy the mountains and the forest. Obviously, however, what the park is most known for is the cave itself which includes at least two different entrances that lead down into the cave.

Unlike Carlsbad this cave system has been known for a long time and as you head through the cave you can see many of the markings made by some of the early visitors to the cave. These marks were made using candles on top of long sticks to allow visitors to write their names in the ash and smoke made from the candles on the roof, and since the cave environment changes very little and the marked areas do not have water in them many names that have been there since the mid-1800s are still visible. This cave has been in use in some form or another since the early 1800s and was originally used as a mine with many of the original settling basins and pipes that were worked by slaves are still visible. The one thing I didn't like about this park was that, also unlike Carlsbad, the only way to view the cave was the be led down by a National Park Service guide. This is due to the cave being more confusing than Carlsbad and the trails having been put in by the Civilian Conservation Corps (CCC) in the 1930's so the trail itself is not paved with railing around it. Overall though if you are in the area I recommend that you check out the cave.

Geology:
I have already covered how caves form from solid rock in the Carlsbad Caverns post (click that link if you want to read more) so the geology in this post will be more about the regional geology.

If you look at the mid-western portion of the United States on a geologic map there are a lot of Paleozoic aged rocks that form the bedrock for that area. This is because for most of the Paleozoic the Midwest was sitting under a shallow sea and the Appalachian Mountains were being uplifted, for the first time, which provided sediment to be deposited in this basin. During much of the Paleozoic North America sat on the equator which provided for a much warmer climate than what is found today especially in some of the more northern states such as Pennsylvania, you can see more of this in my Guadalupe Mountains (Guads) post. Many of the southern portions of this area were not receiving high amounts of sediment though and due to the way the crust bent in the area, the Cincinnati arch, these areas, seen really well from just south of Nashville to Ohio, were shallow seas. These shallow warm seas as we know today are home to calcite secreting organism and other reef organisms. This creates a vast area in the center of the country that is home to lots of limestone deposits which creates what is known as karst topography, which is pretty much lots of sink holes and caves. All of the rock that you see in and around Nashville is limestone or other similar calcite rich rocks.

During the Mississippian, early Carboniferous, the area that is now Mammoth Cave National Park was sitting in a shallow sea and was a highly productive reef system. Throughout many areas of the cave fossil organisms that are now primarily associated with reef systems, such as crinoids [image of a crinoid fossil from the new entrance to the left], are found as fossils in some of the less altered cave walls. This led to a lot of deposition of calcite which is where all of the portions of the cave are now found. During the Pennsylvanian, late Carboniferous, there was a subtle change in the flow of sediments into the basin and a river system began depositing sand in a deltaic system over the area. The sediment from this river would choke off the ability of the reef organisms to live and produce calcite, similar to why there are no reefs near the Mississippi River delta today, and would instead allow just for the deposition of sands and clays. These sands and clays do not erode away as quickly or easily nor are they effected by acidic water the same way that limestone is so they provide a sort of cap rock preventing water from entering the system and dissolving away the rocks below.

Eventually this area began to uplift as well as forms the western portion of the current Appalachian Mountains called the Appalachian Plateau. As this area was uplifted water did what it always does to areas that are uplifting, it started cutting away where rivers were flowing to form valleys, the speed of this uplift is really present in some of the eastern rivers such as the New River and the Shenandoah which appear to meander like river that are no longer down-cutting but they are still down-cutting forming deep valleys (I have the ability to cover that last one and might here soon). Within Mammoth Cave National Park is the Green River which cuts a valley and at one time was much higher up relative to where it is now. It was when it was still cutting a higher portion of this valley that most of the cave that visitors see was being formed. The cave system itself is actually part of the Green River watershed and there are vast underground flowing rivers that carry water from west of the area over to the current location of the river. At one point in the past some of the larger chambers in the upper portion of the cave did the same but as the water table fell, do to the uplift of the mountains, these portions of the cave became dry. In many places the Pennsylvanian sandstone [image at right is an outcrop of the Pennsylvanian sandstone] that formed the cap rock has been stripped away this has allowed water to continue to enter the cave and forms many of the sinkholes in the area. The places where the sandstone is still present form the ridge tops and locations within the cave that have no water dripping into them, because it cannot get through the sandstone, or does so too slowly to be noticed. This creates a stable environment that allowed for the preservation of mummies that first created the buzz for the area before it was a National Park.

More Pictures I have even more in the Mammoth Cave portion of my Flickr page.







Further Reading:

History of Geology's post on the mountains formed by prehistoric reefs (I should really have linked here in the Guads post as well).

National Park Service's webpage on the Natural Features and Ecosystems which has links to many more specialized sections of their webpage.

My post on how the NPS is trying to protect bats in the area.

National Park Service Series homepage

Fort Sumter National Monument

Location: Fort Sumter itself is located in Charleston Harbor, Charleston, SC. Fort Moultrie is located on Sullivan's Island, SC.

Introduction:
This post will be a special post because this is one of the many sites in the National Park System that preserves history of the American Civil War. This site is where the war began! I will admit I haven't been there since 2008 so it has been a while but this post needed to be done today because it marks the 150th anniversary of the start of the Civil War. I am not going to go into too much depth on the history that led to the start of this war because while I may enjoy learning about that time there are much smarter people than I out there that can handle that this post won't be too much unlike the ones that preceded it in this series.

Fort Sumnter National Monument actually contains within it two forts; Fort Sumter itself (Wikipedia Page) and Fort Moultrie (Wikipedia Page). It contains both of these forts because Fort Moultrie is where many of the early shots of the Civil War that fell on Fort Sumter were fired from Fort Moultrie. While you need to take a boat out to Fort Sumter, there are a couple of places around Charleston to pick one up, Fort Moultrie is just a short drive from downtown Charleston and sits on a beautiful portion of beach that overlooks the harbor. When you stand on these forts you can see why they were chosen they both overlook a good portion of Charleston Harbor and would be great places to mount a defense of the harbor. I really enjoyed my visit to these two sites and if you are interested in American history these are a must see as Fort Moultrie was an active fort till just after WWII

Geology:
The geology of the two forts itself is pretty simple, they sit on modern beach deposits formed from sand and in a few places rocks. The City of Charleston itself is primarily a deltaic system so consists of fine grained sediments that have been laid down as the two rivers that from the harbor flooded in the past. This basic geology gives me a chance to talk briefly about the coastal plain of the U.S. east coast, called the Atlantic Plain. The coastal plain in the US starts at the fall line and is primarily associated with, on the east coast, metamorphic rocks to the west and the coastal plain sedimentary rocks to the east. These rocks were laid down slowly as the ocean receded and is the reason why whale fossils can be found just outside of Richmond, VA. These rocks had been cut when the rivers where the lowest during the last glacial maxima but are now flooded, except for the Mississippi River, up to the fall line due to the increase in sea level with the melting of the glaciers. It is an interesting situation but not an overly complex geologic structure.

More Images: I have even more in the Fort Sumter portion of my Flickr page.









Further Reading:

Ok I don't have anything else to read as far as the geology goes but check out the NPS website on the sites to learn more about the history as well as many untold books on the Civil War itself.

National Park Service Series homepage

Carlsbad Caverns National Park

Location: Eddy County in southeastern New Mexico right near the border with Texas, near Carlsbad, NM.

Introduction:
Within about 30 miles of Guadalupe Mountains National Park (Guads), Carlsbad Caverns National Park (Wikipedia page) is the first of the National Park cave systems that I visited. As with the Guads this national park is located in the high desert of the American Southwest. The surface footprint of the National Park is much greater that what would be expected if it was to just be the cave itself and as such there are many other activities to see and do including many great views as well as being able to visit other entrances to the cave system. If you are hitting up one of the two parks in the region you are doing something wrong since they are both so close and both offer many different options to explore.

Geology
As you might expect the geology of Carlsbad Caverns is very similar to that of the Guads so if you have not read my write up on that I suggest you do. A quick summary for those who have but may not remember it all. In the Permian the area that now includes Carlsbad Caverns and the Guadalupe Mountains was covered by a warm, shallow sea that allowed for the growth of organism that secreted calcium carbonate in a primarily sponge-reef. The sea eventually began to dry and covered up much of the reef in evaporites. Overtime these calcium carbonate rich rocks were lithified to form a large primarily limestone deposit. This limestone was eventually uplifted and formed the mountains and ridges in this area.

Now I can expand on something I mentioned in passing when I talked about the Guads is the formation of caves which this post will allow me to expand on. Caves form primarily in limestone rich areas which are typically known as karst areas, why? The answer is simply that limestone breaks down easily in acid rain. All rain has some acidic qualities in it these are picked up as the rain water passes through atmospheric CO2. When the CO2 is present in the atmosphere and gets taken up by water it forms carbonic acid but it is typically pretty weak in the rain water itself. As the rain water can either run off into rivers and lakes and eventually the ocean or it can penetrate the surface and reach the water table. As the water moves underground if it reaches a limestone rich deposit the carbonic acid will react with the limestone, this dissolves away a part of the limestone and releases CO2 back into the atmosphere. This dissolved water is part of the reason why people who have well water will get hard water stains etc a lot of times. Also of some interest this is another reason why scientist worry about excess CO2 in the atmosphere because it causes the oceans to become more acidic making it more difficult for calcite secreting organisms, coral etc, to secrete calcite and can cause them to actually dissolve over time, this is called ocean acidification. Over a long period of time the water can dissolve away large areas of the limestone and form caves and as the water table drops or the area with the cave is uplifted these caves become exposed at the surface where we find them. Another interesting thing that can happen is that the water can get supersaturated in lime at higher subsurface pressures and when this water reaches the surface, or a depressurized cave, it will drop this lime off and form a special kind of limestone called travertine. Travertine is what typically is found on the edges of cave walls as well as in many of the formations in the cave.

Animals have always played a large role in the environment of caves and the most typical animal that people think of with caves is bats. Carlsbad Caverns is no exception to this and during the summer you can watch the bats fly out of the cave at night, I hear this is an awesome sight but one which I have not yet seen. Other animals also use the caves and deep within the cave system it becomes an environment like no other. A karst system can form many openings into the cave system on the surface some of which may be nearly vertical or just impossible for a surface animal to escape from. This leads to the possibility of fossils being found in caves and in fact they have been found in this cave as well as others around the world. If you really wish to learn how these fossils may get preserved I recommend this post over at History of Geology, yes I know I have mentioned it before. I'm sure I am missing some aspects so if you have questions feel free to ask them in the comment section below and I will try to answer them.

More Pictures I have even more in the Carlsbad Caverns portion of my Flickr page.









Further Reading:

National Park Service's web page on the Geology and on the Caves

While only partially related: Bebout, D.G. and Kerans, C. 1993. Guide to the Permian Reef Geology Trail, McKittrick Canyon, Guadalupe Mountains National Park, West Texas. Bureau of Economic Geology, Austin, 48 p. (I really recommend this last one if you are going to do the geology trail (of the Guads) because it includes stops and talks about the geology of the are. A digital copy can be found here but I recommend buying one from the park when you get there [the Guads], support your parks!!!)

National Park Service Series homepage

Guadalupe Mountains National Park

Location: Culberson and Hudspeth Counties in western Texas.

Introduction
Located in the high desert of the American Southwest Guadalupe Mountains National Park (Wikipedia page) is like no other park I had ever been too. This was the first national park that I went to since moving to Texas from Pennsylvania. The park has amazing views from atop of the ridges and many hiking trails to get up there. I only spent a few days out here so I only had time to take one hiking trail, it was the geology trail so that will be helpful. The park also contains the highest point in the State of Texas, Guadalupe Peak. The hikes from the basin up to the top of the mountains are hard, typically over 2000 feet of elevation change with the hikes starting at around a mile high. This drastic change in elevation brings with it a drastic change in climates, from a true desert in the basin up to a cooler and more wet environment up on top of the mountains that allows for the growth of a forest. This park is a geologists dream, why you may ask? Well keep reading to find out.

Geology:
Most of the information from this section is summarized from Bebout and Kerans (1993). As I said this National Park is a geologists dream for a couple of reasons. The first reason is the amount of exposed rock, this is typical of many of the western parks because of how dry try are does not promote the growth of much vegetation. The other reason is what has been preserved. Guadalupe Mountains National Park represents a complete reef system from the deep water turbidity deposits up to the more shallow water reef system. If you have looked at the map you may be wondering how this worked since this park is many hundreds of miles from the present ocean. This was not the case during the time of deposition, the Permian, where the ocean came up to the area that is now the park. If you look at this image you will see two shallow water fingers on the western edge just north of the equator. These two fingers represent the two main portions of what is known in the oil and gas industry as the Permian Basin. The more western basin is known as the Delaware Basin, this is where the park is located, the eastern basin is known as the Midland Basin, this is where most of the oil was found. Back to the park during the Permian this reef was building up but unlike modern reefs that are primarily formed by corals the reef that formed the mountains in the park were actually formed by more hard bodied sponges than what we typically find alive today [photo at left one of these sponges taken by author]. These sponges like modern coral secreted calcium carbonate meaning that the mountains are almost entirely limestone. As I mentioned earlier the full reef system can be seen while walking along the trails. This includes many fossils of the reef builders and those that lived on the reef which unfortunately makes it prone to being looted and having fossils hacked out of the rock itself. The limestone is easily dissolved when it comes in contact with acid, this a very good way to test for limestone and is done in most introductory geology labs (see video here), and because of this there are plenty of caves and similar bodies around the area (foreshadowing of a future post).

What makes the geology of the park even more impressive is that it represents a paleotopography [photo at right of El Capitan by author]. This means that if you are standing at the bottom looking up at the top of the mountains it would about the same elevation change as it was during the Permian millions of years ago only it would have all been covered with water. This is the main reason why the entire reef system is preserved since we are looking at the system as it was millions of years ago. So why is all of this visible now? One of the reasons is that after the reef was formed the shallow sea that covered the area went through periods where there were large amounts of evaporation. This leads to large amounts of salt deposits that cover the region on the way west from Lubbock and the rest of more eastern Texas. This area was probably covered during the Mesozoic and the uplift that formed the modern Rockies began to uplift this area as well. Salt dissolves very easily in water and so as the area was uplifted a lot of these salts were dissolved away this exposed the relatively harder limestones in the mountains and allowed the paleotopography to be shown in the park. Of interest to those interested in the history of oil and gas would be what this all means for that field. The oil and gas in the area is typically found in the limestones that are equivalent to those that make up the mountains. Oil would not naturally stay in a porous rock like these limestones but in areas such as the Midland Basin these evaporties form a great caprock which kept the oil from escaping until it could be reached and it made the region rich in oil money which basically created many of the large cities, like Midland and Odessa, in western Texas.

Guadalupe Mountains National Park shows the geology of the Permian so well that it is in fact home two 2 GSSPs. These symbolize the type sections for the Capitanian, the upper most of the Middle Permian, and Guadalupian, or Middle Permian, rocks. This is really interesting and it is exciting in that there are very rarely two GSSPs in one country let alone that close together.

More Pictures All images below are by the author.









Further Reading:

National Park Service's web page on the Geology

Bebout, D.G. and Kerans, C. 1993. Guide to the Permian Reef Geology Trail, McKittrick Canyon, Guadalupe Mountains National Park, West Texas. Bureau of Economic Geology, Austin, 48 p.
(I really recommend this last one if you are going to do the geology trail because it includes stops and talks about the geology of the are. A digital copy can be found here but I recommend buying one from the park when you get there, support your parks!!!)

National Park Service Series homepage

National Park Service Series

Edit: I have now moved this to a more permanent page so this particular page won't be updated anymore

So I am planning on starting a new series of posts similar to my museum posts. This series will be written whenever I go and visit a new park and have the time to actually write about the trip. I will try to do a little research on the geology and fossils of the National Park before I write the post. The reason I am writing this post is that it will serve as the home page for this series so that all the posts for this series will link back to here and from here you will be able to navigate to all of the individual posts. This will help prevent every post from having a long list on the bottom of it and will require a lot less editing for me and lets not kid ourselves I am lazy.

National Park Posts
Carlsbad Caverns National Park
Fort Sumter National Monument
Guadalupe Mountains National Park
Mammoth Cave National Park