Tag Archives: Indian Creek

Statemap Field Blog, Dec 10-12, 2013

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Hello all!

Well, we did have a winter weather event last Friday that was still on the ground in the field area the following Tuesday.  Roads were fairly clear to Clinton, but between Clinton and Shirley it was still mostly patches of snow and ice.  North of Shirley, the roads were pretty much all covered with snow and ice.  Even “Goldy” (our Jeep) got stuck briefly when Danny decided to stop and check his map almost at the top of a hill.

Tuesday we managed to get to a drainage south of the Middle Fork that had fairly low relief, so were able to climb down the side and follow it on down.  There were some very large footprints in the snow along the valley floor that may have been a feral pig, but don’t know for sure.  It’s amazing how the critters always choose the easiest route.  Their trails are usually pretty good for people too, though they don’t often care about avoiding briar patches.  The snow was pretty crunchy, so fairly good traction.  Having snow on the ground rather evens out the terrain in an odd way, though you have to be poised to catch yourself with every step.  Had some massive sandstone units, but they were blocky and non-calcareous, so we’re in something different than on the north side of the river.

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The next day we managed to make our way north of Shirley to a couple drainages at the head of Indian Creek that we had skipped when we did the lower end.  As it happened it was a pretty good choice because the relief was rather low and the bottom was fairly wide.  Also, it was south-facing which helped to melt the crusty snow and maybe keep us a little warmer.  We saw mostly massive calcareous sandstone units of the Witts Springs though may have gotten into the Bloyd in the higher elevations.  At the end of the day we entered an area that still showed signs of damage from the Jan. 2009 ice storm that coated most of northwest Arkansas with a thick layer of ice and downed many trees–many by the roots.  Witnessed a beautiful sunset on the way out though.  We were near 1400 feet which is about the highest elevation on the quad.  The trees there were still coated in ice from last Friday’s storm.

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Thursday we tried another drainage near the one we hiked on Tuesday.  This one was north-facing and proved to be too steep and narrow a descent to do with so much snow on the ground.  The snow had developed a thick icy crust from thawing and refreezing, and we had to break through it to get traction.  I managed to get up and around on the side of a particularly narrow spot in the creek bed, and was waiting for Danny to follow when I saw him retreating back upstream.  I later found out that he couldn’t find purchase on the icy banks, so decided to return the way we had come.  Since I had gotten farther downstream by breaking through the crusty snow and climbing down the steep side, I had no choice but to climb back up that way.  I found that going on up was less hazardous than going back down toward the creek, so I continued to climb up the side and by the time I drew even with Danny was probably 100 feet higher.  I could barely see him down there, but managed to get a photo of him climbing up the drainage.  We’ll have to try that one again when the snow is gone!

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After that, we got a few points on Weaver Creek were it leaves the western edge of the map, and headed back to Little Rock.  Hope this clears up by next week!  Until then, see you on the ice-covered outcrop!

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Statemap Field Blog, Sept. 23-25, 2013

Hello all!

Another good week in the field!  Temperatures are getting low in the morning, but still warming up in the afternoon.  We started out by finishing up the rest of Tick Creek at the north edge of the map.  Got the lower Cane Hill sandstone up Files Hollow and again on the east side of Tick.2013-09-23 001  2013-09-23 014Still have good channel-bedded Imo below in the creek bed with a shale unit between the two.

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Tuesday and Wednesday we finished up the lower end of Indian Creek.  There were several massive-bedded sandstone units that had cut down into lower units of thin- to medium-bedded sandstone interbedded with shale.

This is probably all in the Witts Springs Formation, but we won’t know for sure until we see more of the rock in the area.  One of the indications that it is Witts Springs sandstone is the characteristic curved reentrant at creek level.  This is caused by exfoliation or spalling of curved sheets of rock due to more rapid dissolution of the calcareous cement near the creek.  The Witts Springs sandstone is typically more calcareous than overlying formations.    2013-09-24 0452013-09-24 060

You never know when you might see a classic example of a sedimentary structure while hiking around.  This week we saw some good examples of load casts in the creek float.  A sand deposit formed an irregular bulge as it pressed down (loaded) into the mud below.  Later lithification preserved the cast of that shape on the bottom of the sandstone bed.

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As we approached the southwest/northeast topographic lineation along the Middle Fork at the mouth of Indian Creek, we began to see more and more signs of a major structure.  Aside from a 5 to 7 degree southeast dip, there was an increasing abundance of deformation bands in the massive sandstone.   Also, we began to see a lot of non-vertical joints and small faults.  Took photos of a couple of fault planes with the slickensides still evident.2013-09-25 013  Slickensides are the parallel grooves or scratches left behind on the fault plane caused by the abrasion of one rock surface against another.  They are typically smooth in the direction of movement and rough in the opposite direction, so can indicate which way the fault moved.  Unfortunately there is no way to estimate throw, or the amount of offset on the fault, without knowing which formations are on either side.  That’s why we’ll have to be extra thorough in that area.  There’s probably a big fault somewhere along that lineation, but we’ve yet to find it so far.

By the way, Indian Creek must have gotten its name from the number of moccasins lying around.

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We’re taking a little hiatus next week so will be at least two weeks ’til the next installment.

See you on the outcrop!

Snake count: at least 4

Tick attacks: still severe