Archive for the ‘Ozarks’ Tag

Ouachitas & Ozarks Part II   8 comments

The Ozarks are a land of limestone and blue-green rivers.

This post continues a mini-series on the Ouachitas and Ozarks that I started last Friday.  Check out Part I before reading this one.

HOW THE OZARKS CAME TO BE

So let’s continue with the geology of the Ozarks.  If you’ve been to other places in the world with a lot of limestone caves, and if you’re observant, you’ll recognize a distinct type of terrain in the Ozarks: karst topography.  Karst is made up of steep but not very high mountains.  Most all karst lies in lower latitudes, so it tends to be forested.  Caves, sinkholes and underground rivers are very common in this kind of terrain.  You may at first glance find it hard to recognize karst in the Ozarks.  But because of their great age, the karst here is more subtle than that of, for example, the Malay Peninsula or southwestern China.

This classic karst terrain in southern Thailand is obvious because it is young.

This classic karst terrain in southern Thailand is obvious because it is young.

Still, karst topography anywhere is not easily missed.  In the middle Paleozoic Era, some 350 to 450 million years ago, the Ozarks were what geologists call a carbonate platform, a sandy seafloor interrupted occasionally by shallow reefs.  But “carbonate platform” is too dry a term for me.  It was in fact a warm, tropical sea, filled with marine life and dotted with islands.  To put it even more simply, it was one of the many pre-human paradises that have existed on Earth.

Like today, the marine life was dominated by tiny planktonic (free floating) organisms.  But there was also a very abundant sessile community (seafloor-dwellers like clams, etc.).  Finally there were free swimmers like early fish and many squid-like creatures.  Early sharks, which came in a variety of weird forms, patrolled the waters.

Most of the life in that ancient sea made their shells out of calcium carbonate, pulling CO2 out of the seawater and in the process helping to keep the world from warming up too much.  When these little critters died they drifted down and accumulated on the sea floor.  The limy sediment piled up, later to form limestone rock thousands of feet thick.  The world’s largest lead-zinc mines occur in the Ozarks in what’s called the Viburnum Trend.  Abundant lead and zinc occurs characteristically in thick stacks of limestone.

Limestone, originally laid down in a warm sea, lines the Buffalo National River, AR.

Limestone, originally laid down in a warm sea, lines the Buffalo National River, AR.

While the Ouachita Orogeny buckled and broke the land to the south, thrusting up high mountains, here in the Ozarks it simply lifted the carbonate platform straight up into a shallow dome-like plateau.  (It also lifted up the entire southern part of the Great Plains.)  When the limestone was lifted, it began to be subjected to the effects of a groundwater.

The water table is always changing with time.  In wetter climates the limestone bedrock lay submerged in mildly acidic groundwater, which slowly enlarges fractures, dissolving out cavities.  In drier times the rock was above water table.  This is when familiar features like stalactites and stalagmites would form. The evolution of caverns only halts when erosion of the land above reaches them and they dry out.  But without these often well-hidden openings, the Ozarks wouldn’t be one of the best places to go caving in North America.

A river you can boat on runs deep into this limestone cavern in the karst of southern Laos.

TRAVEL BASICS

As in much of the U.S., renting a car is the only realistic way to see much.  A regular two-wheel-drive sedan will do fine in this part of the country.  Flying in you can try to get a relatively cheap flight to Fayetteville or Little Rock, Arkansas.  Oklahoma City (4-5 hours by car) or Dallas (7 hours to the Ozarks, 4 to the Ouachitas) are also options.

Often when you’re looking at exploring a region, you can save money by flying relatively cheaply to a town that relies on tourism.  There’s a good chance you’ll be able to score a cheap rental car too, then you can skip town and drive to your preferred (less touristy) destination.  It works well as long as your tourist-town gateway isn’t too far from where you’re going.  Las Vegas, only a few hours away from Zion National Park, is a good example.

A stream running through a cave in the Ozarks drops into a pretty little pool.

A stream running through a cave in the Ozarks drops into a pretty little pool.

For the Ozarks, try looking into the town of Branson, Missouri.  Lying smack dab in the Missouri Ozarks, Branson has gambling and country music and you either love it or hate it.  You might be able to get good flight and rental car deals to and from Branson.  A flight to Dallas will still probably be cheaper, but remember to factor in gas and time when making a decision.  For the Ouachitas, try Hot Springs, Arkansas.  It isn’t as hot a tourist destination, but there’s a National Park.

Once you arrive and have transport, there are numerous potential base-towns that offer anything you may need, plus a great diversity of lodging.  A couple larger ones are Hot Springs, Arkansas (home town of former president Bill Clinton) and Fayetteville, AR (home of the Razorbacks – college football is big in this area).  Small towns are quite numerous, and fairly cheap motel rooms can be had in most of them.

Camping is possible in the Ouachita National Forest.  Simple and basic as always, National Forest campsites here are often located beside lakes stocked with fish.  Good state parks can also be found.  Magazine Mountain State Park in Arkansas hosts an excellent state park with great hiking trails, camping and a beautiful lodge with outstanding views.

Campsite: Oachitas, AR

MAGAZINE MOUNTAIN

I went to Magazine Mountain because it was the highest peak in the Ouachitas.  While you can hike a short trail to the summit, trees prevent much of a view.  What you will see up there is an amazingly large map of Arkansas made of stone!  Better views are found along the ridge-lines leading from the summit.  A few miles south of the turnoff to the lodge, along Hwy. 309, a small scenic overlook beckons you to stop.  From here you can walk the trail a hundred yards or more for even better natural stone viewing platforms.

A large picnic area off the east side of the road just uphill from the overlook makes a good place to eat lunch, and is also a good spot from which to go hiking.  The lodge at Mt. Magazine is on a side road that takes off west of Hwy. 309.  At this intersection there’s a small but nice visitor center.  Stop and learn something of the local plant and animal life, get maps and hiking tips, and fill up a water bottle.  The lodge is pretty luxurious.  I don’t know the prices and they’re not listed on the web, but Google them and call or email.  There are cabins, rooms and suites, all with splendid views.  A restaurant that serves good basic meals is onsite as well.

Magazine Mountain is the highest peak in the Oachitas at just over 2800 feet, and this is a view from near the summit.

Magazine Mountain is the highest peak in the Oachitas at just over 2800 feet, and this is a view from near the summit.

The Benefield Loop, Bear Hollow and North Rim trails have the best views at Mt. Magazine.  Don’t forget the camera; you’ll have many photo opportunities at both large and small scales.  The sandstone here is harder and more resistant to erosion than surrounding shale, so it stands up, forming stunning overlooks (see above).  It’s tempting to put a friend/subject/victim out on one of these and photograph them looking heroic.

The rock outcrops also host very interesting lichen and moss, and in summertime beautiful wildflowers spring from its crevices.  You may find your macro lens getting a good workout at Mt. Magazine.  Keep an eye out for deer on the roads of course, and watch for snakes too, especially as it warms up in spring.  There are venomous (but not deadly) copperheads here.

Ancient sandstone in the Ouachita Mountains is typically encrusted with moss and lichen.

Ancient sandstone in the Ouachita Mountains is typically encrusted with moss and lichen.

I best leave it there.  The next installment will highlight some of the region’s cultural history and describe a few nice spots to visit and photograph in the Ouachitas and Ozarks.

Ouachitas & Ozarks, Part I   12 comments

Instead of Friday Foto Talk this week, I’m pausing to do something I haven’t done in quite some time.  If you haven’t been reading this blog for long, you probably think I only do posts on photography.  But my real love is exploring and learning about new places.  In particular I love the land and how people have been relating to it and to each other over the ages.  I tend to go for off-beat places lying “in-between” the well known destinations.

I don’t totally ignore the more touristy places.  After all, nearly all of them used to be charming little spots, and that charm often lies just beneath the surface.  But I don’t take trips without making time for detours.  As an example, this blog actually started out when I did a 4-month trip to Africa.  If you have time, you might check out some of the posts from that journey.

Arriving at night, I camped on top of this ridge and woke to a chilly but beautiful autumn morning in the Oachita Mountains of Arkansas

AN IMPROMPTU TRIP

This post is about a place I wouldn’t have thought of visiting if not for the fact I was working nearby and had some time off to explore.  The southern U.S. is a culturally distinct area of the country.  It’s the most conservative part of the U.S., and religious fundamentalism has a home there.  But the region is also renowned for its polite respect and hospitality.

A liberal may not agree with much of what the people believe here, but they also might be treated much better than in friendlier ideological confines like California or Massachusetts.  Unfortunately, in recent decades, that culture has been diluted by the ongoing homogenization of the world.  In that respect it’s no different than many other places.

Interesting purple berries, western Oachitas.

INTRODUCTION

The Oachitas and Ozarks of Arkansas, eastern Oklahoma and southern Missouri are an interesting area of low mountains and forests, small towns and farms.  Outstanding quartz crystals are found among pine forest in the Oachitas.  In the Ozarks streams flow from numerous caves.  Between the Appalachians and Rocky Mountains, this is some of the only high country you’ll find in the U.S.

The word Oachita (pronounced wosh-i-TAW) comes from the Choctaw tribe’s word for the region.  It means place of large buffaloes.  Sadly, bison no longer roam free here.  The word Ozarks is derived from the French term aux arcs, referring to either the top bend of the Arkansas River or to the large number of natural bridges and arches in the area.

A good time to visit the Oachitas and Ozarks is in autumn, when the leaves of the oak and hickory turn golden and red.  That happens in mid-October through early November most years.  There is probably a little more fall color going on in the Ozarks than in the pine-rich Oachitas.  Summers are hot and humid, but there are plenty of lakes to cool off in.  Winters are fairly mild but cold, snowy periods are not uncommon.  Early to mid-October is a perfect time to visit.  Springtime (March to April) is also great.

 

A farm in the fog, Ozarks, Arkansas.

OACHITAS GEOLOGY

I always start with this when talking about a place.  Blame it on the fact that I did it for nearly 20 years.  Or maybe I read a lot of James Michener when I was young.  The Oachita Mountains are the remnants of a once-mighty mountain range.  We can’t be sure exactly how high they were, but think of the modern Rocky Mountains of Colorado and you have the idea.

The reason these mountains are so mellow (some would even call them hills) is the combined effects of water, gravity and time.  By the way, I don’t call them hills because I know about their long, grand reign.  You wouldn’t call an old man who had seen and done great things a boy, now would you?

Like many (but not all) mountain chains, the Oachitas formed from the collision of two tectonic plates.  About 300 million years ago, well before any dinosaur walked the earth, the South American continent, coming from the south, collided with North America.  An ocean was destroyed in the process.  Much later it was resurrected as the modern Atlantic, with the Gulf of Mexico butting up against the southern U.S.

The Oachita “orogeny” (mountain building event) created what is called a fold-thrust belt.  Folds in layers of sedimentary rock are just like when you push a rug against a wall.  Thrust faults are like pushing one rug over top another.  Yep, tectonics is like your living room!  The Alps are the classic example of a fold-thrust belt mountain range.  But they are much younger than the Oachitas and Appalachians.  The latter are characterized by long ridges separated by broad valleys.  The ridges stand up because erosion has cut into the folds and exposed harder rocks like sandstone.

Diagram of a fold and thrust mountain belt.

These folded mountains in the northern Rockies of Canada may be what the Ouachitas once looked like.  This is not my shot but I’ve been told it’s probably an old Geological Survey of Canada image (which makes sense).

The sandstone, shale and limestone that make up the Oachitas were formed many millions of years before they were crunched by the Oachita Orogeny.  The area was covered by thousands of feet of seawater, and the nearby coast was flat and quiet, much like the modern-day east coast of South America.  Sediments were deposited in the quiet waters of a Paleozoic sea, precursor to the modern Atlantic.  As that ocean was destroyed in the collision, the seafloor rocks and sediments were caught in a giant vise.  They buckled under the stress of collision, eventually rising to form a fold-thrust mountain belt.  Because the pressure was directed north-south, the mountains run east-west.  They’re the only mountains in America that run in this direction.

The southern Appalachian Mountains, as seen from space, are shown curving toward the east-west orientation of the Oachitas to the west. Click to go to the source site for this image.

The southern Appalachian Mountains, as seen from space, are shown curving toward the east-west orientation of the Oachitas to the west. Click to go to the source site for this image.

On a curved surface like that of our planet, mountains don’t run in straight lines forever.  The Oachitas are part of a very, very long arc of ancient mountains, extending thousands of miles from Maine to Texas.  The Appalachians, which are themselves quite long, extend to the west.  They are interrupted by the Mississippi embayment, but pick up in central Arkansas as the Oachitas.  Even further to the west, the range is submerged beneath younger rocks, popping up as the Wichita Mountains of Oklahoma and the Marathon Mountains of west Texas.

The Oachitas are known for their beautiful quartz crystals and also for novaculite.  Novaculite is a very fine grained, hard flinty rock that resembles flint or chert.  It’s easily knapped or flaked, and as such made this area a magnet for newly arrived humans some 12,000 years ago.  These hunter-gatherers were looking for good raw material from which to make spear-points.

As a bonus, the Oachitas also provided deer, bison and other animals to hunt with those spear points.  Both the crystalline and the micro-crystalline quartz (novaculite is micro-crystalline) were created when fluids from deeper in the crust rose and filled the pervasive fractures formed during mountain building.

Novaculite from the Oachita Mtns., Arkansas

Novaculite from the Oachita Mtns., Arkansas

OZARKS GEOLOGY

The Ozarks lie north of the Oachitas.  In ancient times (and I do mean ancient), the North American continent was smaller, with a coastline to the north of the Ozarks.

**Sorry, I just have to go on a tangent:  Although there have been a few periods in Earth’s history when all the continents joined together into super-continents, most of the time it’s been like today, continents separated by oceans.  But in the distant past continents were smaller and oceans bigger.  It’s one reason we have so much darn limestone around (that rock forms in shallow seas).  Pangea, which you may have heard of, was the last of the super-continents, and it came together after the Oachitas formed.  In fact, the tectonic collision that led to the rise of the Appalachian-Oachita mountains was a big event leading to the coming together of Pangea.

We’ll have another super-continent again sometime in the future, but the bigger picture is this: continents started out quite small and have grown steadily larger over billions of years.  This means big things for carbon, the basis of life and (combined with oxygen) the ultimate controller of climate.  It means more carbon will be soaked up by weathering and stored away in limestone and other rocks.  Of course this has always happened and we’ve done just fine.  Carbon has been dragged with it’s enclosing rocks down into the mantle by subduction, and then recycled back into the atmosphere in volcanic eruptions.  It’s what has kept earth from freezing over.

But with bigger continents comes more weathering.  With relatively shorter coastline and less ocean comes fewer volcanoes.  The net effect will probably mean less efficient long-term carbon cycling, and declining ability for the planet to resist ice ages.  It will mean less carbon for life and less carbon dioxide for the greenhouse effect.  This trend won’t become noticeable for quite some time.  But after the current episode of global warming plays itself out, we will return to a long-term cooling and drying trend, one that has been in place for about 30 million years.  We probably won’t freeze over, because the sun has been gradually getting hotter ever since the solar system’s formation.

While this trend will have big effects on climate, evolution tends to triumph over those kinds of changes.  But having less carbon around has crucial implications for life.  We’re living, most probably, in the latter stages of life’s heyday.  Though life began some 3.5 to 4 billion years ago, it only really got going about a half billion years ago.  It saw its peak sometime between 150 and 35 million years ago, and has been slowly declining ever since.

You may have heard that the sun will expand in about 5 billion years, destroying the earth and us in the process.  That will happen.  But unfortunately, all complex life (including us if we don’t evolve into a space-faring and/or partly synthetic species) will likely have disappeared long before that.  In fact, we might have only about a billion more years of habitability here.  Tiny one-celled organisms may be the only thing to witness the expansion of the sun to its red giant stage.  Nothing lasts forever, and that goes for both good times and bad.  I think there’s a lesson to be learned here.  Enjoy life!  And guard the precious ability of our Earth to shelter it.

I’ve gone over on length with this one, so I’ll leave it there and continue next time with more on the Ozarks, plus some interesting cultural history.  I’ll have tips for travel and photography in this interesting area as well.  Have a great weekend!

Instead of a sunset, here’s one captured at night along the Buffalo River, AR.  The full moonlight was filtered by heavy fog, creating a mood that was a little spooky.

Wordless Wednesday: The Ozarks   13 comments

_MG_9709-2

%d bloggers like this: