Tag Archives: Middle Fork Little Red River

Statemap 2014-15 Update

2014-08-04 006

Hello all,

Just wanted to let you know that the Statemap 2014-15 field mapping project has resulted in the publication of three new geologic maps.  These are the Parma, Prim, and Greers Ferry quadrangles.  Reduced images are posted below.  These should be available as .pdfs on our website in the near future.  I’ll keep you posted!Parma

Parma Quadrangle

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Prim Quadrangle

Prim boulder (cannonball concretion) in Sugar Camp Creek

Greers Ferry Layout

Greers Ferry Quadrangle

Old Terrace deposit underlying Greers Ferry, AR

Also, I would like to thank the many people who helped with data collection in the field this year, without whom this project would have been impossible.

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Andy Haner                                                        Danny Rains

 

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Angela Chandler                                                                     Stefanie Domrois

 

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Doug Hanson                                  Ty Johnson

Thanks, everyone!

 

Now it’s off to the Brownsville quad for next year!

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Richard Hutto

Statemap Field Blog, April 7-9, 2014

2014-04-07 006

Hello all,

Well, this is the last week of field work for the 2013-14 season.  Of course, there’s always more one would like to have a look at, but we have to stop sometime.  On Monday, we started down by the M&NA railroad bridge at Shirley.  The big fault that makes the SW/NE lineation goes through here somewhere, but it’s difficult to say where exactly.  There are lots of non-vertical joints and deformation bands in the area, which are all good fault signs, but nothing very definitive.  The area north of the bridge is about as thick as it could possibly be with greenbriers –only passable with much effort and many scratches.  We saw very thick-bedded sandstone there which we took for Witts Springs that day, but when we came back on Wednesday, we decided it may be north of the fault, and therefore would be Imo.  We have Imo across the valley, so it’s not out of the question to have it here, but it may be just a relatively thin slice.  There are many cut and fill channel beds there, some of them with very nice soft-sediment deformation at the margins.

On Tuesday we finished up some loose ends in the northwest corner of the Shirley quad.  After we climbed way down in a hollow that had an old tornado track going through it, Danny realized he had lost his camera somewhere.  We hiked back up to the Jeep to see if it was there (it wasn’t), then retraced our steps from earlier that morning.  Still nothing.  He remembered the last time he had used it was in that horrible briar patch the day before, so after we climbed out again, we headed back there.  Sure enough, in the thickest part of the patch, where he had been practically crawling to get through, a briar had reached in his carrying case and pulled it out.  It was still dangling there about a foot off the ground right on the river bank.  At least we got it back!

Deformation bands in massive sandstone near Middle Fork north of Shirley2014-04-07 017

2014-04-09 026 2014-04-09 011On Tuesday afternoon, we went down a drainage on the west side of Middle Fork looking for more signs of a fault we have traced from the Old Lexington quad.  We definitely found a lot of deformation bands in the Witts Springs massives down there and figure there might be as much as 80 feet of throw on the fault.

2014-04-08 0192014-04-08 027Wednesday was our last day in the field this year, and we spent most of our time on the Middle Fork just north of Shirley where we had left off on Monday.  Did look like the fault goes through there because we found very-thick bedded massives on the north side (Imo) and shale interbedded with very thin-bedded sandstone on the south side (Cane Hill).  Our last couple of hours we spent getting points in several road cuts in and around Shirley.  We took a final photo in front of the town sign.

2014-04-08 048 (2)2014-04-09 047This will be Danny’s last year out in the field with me, so I’d like to take this opportunity to thank him for putting up with me and the sometimes horrendous field conditions we’ve faced together the last five years.   Looks like I’ll have to break in a new field partner next year, so should be interesting.  Now comes the time of year when we have to sit in the office and draw the maps, create the layouts, and finish the database, all to be turned in to the USGS by June 30.  It seems like a long time, but we’re always editing down to the last minute.  By the time we make it back out in the field, it will be mid-July, so the ticks and snakes will be out in full force, it will be nice and hot, and all the vegetation will be full grown.  At least that gives us something to look forward to.  Until then, I’ll see you in the office.  After that, I’ll see you on the outcrop!

 

 

 

Statemap Field Blog, Sept. 16-18, 2013

Hello all!

Another great week in the field!  Temperatures are coming down some which makes things much more bearable.  Monday we came down from Fox and crossed the Middle Fork at Lydalisk.  Went as far south on the old railroad grade as we could then worked our way back, getting points along the way.  Still finding the Imo near the bottom of the valley.   The river was so low that we could actually cross it on foot to get a drainage on the east side.  The first good outcrops we found there were the lower Cane Hill.   There were good examples of taphoni in the rocks there.  Commonly known as “honeycomb weathering”, taphoni is caused by weathering processes in many rock types and under many conditions.  In the Cane Hill it typically affects the thin-bedded sandstones in dry areas beneath overhangs and is probably due to differential dissolutioning of the cement by groundwater.  This process also causes the concave structures as noted in previous blogs.

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The next two days we started at the upper end of Indian Creek and worked our way down.  Lots 2013-09-17-019_thumb.jpgof Fayetteville shale production going on in this area, which means good roads for us!  Seemed to be in Witts Springs sandstone the entire stretch, so not a lot of contacts.  Definitely had a lot of dipping rock and signs of  a large fault further south including deformation bands and non-vertical joints.  Located a couple small faults with what we think is minimal offset along the creek and adjacent hollows.

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Cottonmouth in dry creek bed.

Did have a few encounters with our reptile friends.  We always leave them be so maybe word will spread among their kind that we mean no harm.  It’s worked so far!

See you on the outcrop!

Snake count: 2

Tick attacks: severe

Statemap Field Blog, Sept. 3-5, 2013

Hello all!

Well, it warmed up again this week, but at least the humidity stayed lower.  Definitely getting a more golden quality to the sunlight in the evenings now, and the mornings are almost pleasant—maybe fall is just around the corner! 

Kinder Slough on Middle ForkSpent this week exploring lower Tick Creek which is one of the larger tributaries on the north side of the Middle Fork north of Shirley.  I can attest that this creek is aptly named.  It seemed that every plant above ankle high must be covered in them.  Danny and I mapped the upper end of this creek in the 2011-12 field season on the Fox quad.  It was all Cane Hill there with a cap of Witts Springs near the top.  This week we found Imo in the main channel a couple miles from its confluence with the Middle Fork, but haven’t found the contact with the Cane Hill yet.  Will look closer to the north edge of the map next week. 

Flood debris in lower Tick CreekAccording to local landowners, there was a 6-inch deluge at the end of May that washed out many of the access roads.  We could corroborate this after seeing all the large trees and other debris that had been piled up in the creek bed by the flood.  It looks like the entire valley may have been filled with water during that event.  Another good reason not to build anything in the floodplain of these steep-sided, narrow hollows in the Ozark uplands.  Where Still Hollow empties into Tick Creek, a small delta had developed during the flood event.Alluvial fan in Tick Creek 

There was also fresh cutting of the alluvial deposits along the stream bank which plainly showed a typical fining upward sequence.

 

Typical Cane Hill in small drainage to Middle ForkWe walked up quite a few side drainages along Middle Fork and Tick Creek to see if we could catch a glimpse of the Imo as it reaches the bottom of the Middle Fork valley, but the breakdown of the Cane Hill and Witts Springs above has covered it almost entirely.  That left us with thin-bedded Cane Hill sandstone as the lowest unit that produced a decent outcrop in these smaller branches. 

Slide block in creek bedMaybe we’ll get lucky when we hike up the sides of the Middle Fork north of this area.  We did see a large slide block that had fallen into the creek bed and was weathering away virtually intact.  If we had encountered that rock in isolation without the adjacent outcrop, we may have thought there was a fault close by due to the extreme inclination.  As it was, it’s just an interesting footnote to be filed away then used to cast aspersions on future structural theories based on similarly dipping rocks. 

 

What we did see of the Imo upstream in Tick Creek has a lot of interesting lithology (rounded siltstone concretions and coalified wood prints in shale) and bedding structures (soft sediment deformation).  Can’t wait to see what we’ll find upstream!

Snake count: 1

Tick attacks: severe

STATEMAP Field Blog August 26-28, 2013

Hello all!

This week was a hot one, so we did some creek work, but also did some road work.  Went up a section of lower Lost Creek on Monday.  Narrowed down the Cane Hill/Imo to a fairly small area.Danny on Cane Hill in Lost CreekSand on shale in the Imo on Lost Creek

Saw more nice trace fossils in the Imo.

Trace fossils in ImoTrace fossils in the Imo

Got a few points on the Middle Fork where it leaves the Shirley quad and enters Greers Ferry Lake.

Thin-bedded sandstone in Middle Fork Little Red RiverThin-bedded sandstone in Middle Fork Little Red River

Quarry near Fairfield BayAlso, took points on a 4 different shale pits or quarries.

Green persimmons
The persimmons aren’t quite ripe yet!

Deformation bands in massive sandstoneFound these deformation bands right by Highway 16 near Fairfield Bay.  These bands are associated with structural features like faults and folds.  They form in more coarsely grained sandstone when the stress crushes the individual sand grains along a plane, then recrystallizes to form a slightly more resistant lithology, that when weatherd, stand in slight relief.   We will keep looking in this area for more clues and hopefully figure out what the rocks are trying to tell us!

Snake count: 2

Tick attacks: severe

STATEMAP Field Blog—August 19-21, 2013

Hello campers!

Well, much drier this week, but of course the heat is back!

We’re still working on the Shirley quad this week.  Started out Monday by dropping down a steep side drainage off Nubbin Ridge nearly to the Middle Fork, then right back up another one.  Got good points at the base of the Witts Springs and Cane Hill.  The Imo is at the bottom of the valley but the very large boulders eroding at the top cover most of it.  Relief was around 400 feet.

Tuesday and Wednesday we were back in the headwaters of Lost Creek.  There are many branches to this creek, and there seems to be a fairly large structure crossing them approximately east/west.  Could be a fault, or maybe just a fold of some kind—will take much more data collection to be sure.  We did observe a repeating sequence from higher elevations to lower—now we just have to figure out which formation they are in!  In the Ozarks, the Pennsylvanian-aged rocks are a series of sandstone and shale units deposited in a shallow marine environment.  That means they are all very similar to each other and the differences are subtle and vary from place to place.  To differentiate one formation from another, we depend a lot on context, which means we must take meticulous notes on each outcrop in the hopes we can see a pattern in the stratigraphy that matches something known.  We’re starting in the northwest corner of Shirley because we’ve already mapped the surrounding quads in that area, so have a pretty good idea of the geology there.  Things are getting more complicated as we reach the structure because the strata are displaced somewhat from one side to the other.  We will continue to add points next week in order to discover what the rocks are doing there.

ripple beds

ripple beds

Since I’ve mentioned some of the formations in the area and how difficult they are to differentiate, let me discuss one that has stayed fairly consistent across the Boston Mountains Plateau.  The Cane Hill is a Member of the Hale Formation, and its type section is in northwest Arkansas.  It is typically very thin- to thin-bedded, ripple-bedded, very fine-grained sandstone with interbedded shale and thicker shale units.  There are abundant trace fossils in the Cane Hill including asterosoma which is a somewhat star-shaped feeding burrow.

Trace Fossils:

Asterosoma:

concave solutioning in thin-bedded Cane HillBluffs of this sandstone often affected by a particular weathering phenomenon where the cement holding the sand together actually solutions out which lets the individual grains fall away eventually forming a concave structure.  I have included a good set of photos of the Cane Hill and a few of its characteristic structures.  It is getting to be over 300 feet thick as we continue to map toward the southeast.

See you next week!

Snake count: 2

Conostichus count: 1

Tick attacks: moderate to heavy

STATEMAP Field Blog August 5-7, 2013

Hello campers!

Wild grape clusterWell, this week we continued to work down the Middle Fork.  We started out on Sally Flat again, but this time came down the west side.  We were told there had been a tornado through the area a few years ago, but this week we actually encountered large areas that have become inpenetrable due to downed trees and subsequent overgrowth of the understory.

Entrance to fracture cavernFracture cavern in basal Witts Springs sandstoneOn Monday, had a good trail to a fracture cavern in the basal Witts Springs sandstone, and a fine overlook of the Middle Fork valley.  Ended the day with a 500 foot drop to the Cane Hill/Imo contact in a small drainage and back up.

View north from the end of Sally FlatOverlooking the Middle Fork valley

Lute Mountain Road appears impassableThe next day we tried to come down the north end of Lute Mountain Road to get to Lydalisk, but that proved impracticable because it’s even more gullied out than last time I was down it 5 years ago.  That meant we had to go around through Arlberg which took a much longer.  Meadow Creek had come up during the night, and was swelling the Middle Fork considerably below its confluence.  It began to rain as we searched for the next big hollow south, and even though it stopped fairly quickly, the leaves continued to be wet and drippy the rest of the day.  Went up a long hollow west of the river and got good contacts at the base of the Cane Hill and the Witts Springs.  The Cane Hill was exposed almost continuously in the creek bed and is nearly all sandy in this area.

Cane Hill in the jungleAre we ever going to get to the top? More Cane Hill Watch your step!

The author on the Middle Fork-I've mapped the geology of this river all the way to Tilly.

The author on the Middle Fork-I’ve mapped the geology of this river all the way to Tilly.

On the way out we found a new fossil locality in the Imo shale.  Nice calcareous siltstone concretions encrusted with pyrite and fossils with a few solitary crinoids, gastropods, bivalves, and rugosa in the shale.  Looked up a small hollow for a cave marked on the topo, but were disappointed.  Wednesday, we decided to walk the Lute Mountain Road to get some points on the north end of the mountain and down along the west side of the river.

It was a good idea because everywhere else along there is much steeper.  Again we found good Witts Springs/Cane Hill/Imo contacts.  The walk out was quite a climb, and after exchanging our drenched clothes for dry ones, we drove back to Little Rock.

Lepidodendron in Imo sandstone

Snake count: still 0

Tick attacks: low to moderate

Conostichus count: 1

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