What kind of water formation is this?

[bugo]

If you scroll to the south, there's a small river that runs from east to west.  The body of water in question is uphill from the river.  My friend calls it a "slough" but it looks more like an oxbow to me.  What is it?

http://goo.gl/maps/omd3L

[mgk920]

It looks to me like a small depression in the rugged landscape that happens to play host to what I would call a small 'lake'.

'Oxbows' are former sections of river in a floodplain that, at some point in time, the river decided to bypass.  That area does not look like a floodplain.

Mike

[J N Winkler]

Could it be a karst lake?

[Alps]

I know what it looks like, but I refrain in mixed company.

[Brandon]

If you scroll to the south, there's a small river that runs from east to west.  The body of water in question is uphill from the river.  My friend calls it a "slough" but it looks more like an oxbow to me.  What is it?

http://goo.gl/maps/omd3L

It looks like a slough.  An oxbow would be a former channel of a river such as the Mississippi (to use a large example).  We have a lot of these around here due to the post-glacial terrain.

[triplemultiplex]

A slough is any backwater area adjacent to a river that usually was part of the river channel at some point in the past.
An oxbow is a specific type of slough that forms that familiar horseshoe shape.

Over time, the main channel of low gradient rivers tend to migrate back and forth across the valley as sediment is eroded from the outside bends and deposited on the inside bends.  This can lead to abandoned channels and oxbows.

Another thing low gradient rivers tend to do is deposit natural levees along side the main channel during floods.  These can eventually build high enough raise the bed of the river above the level of the floodplain away from the natural levees.  When this happens, the channel can shift into the lower area of the floodplain and abandon large stretches of channel.  This looks like what happened at this place in Arkansas.

I've had some edumacation in the area of fluvial geomorphology. 

[bugo]

A slough is any backwater area adjacent to a river that usually was part of the river channel at some point in the past.
An oxbow is a specific type of slough that forms that familiar horseshoe shape.

Over time, the main channel of low gradient rivers tend to migrate back and forth across the valley as sediment is eroded from the outside bends and deposited on the inside bends.  This can lead to abandoned channels and oxbows.

Another thing low gradient rivers tend to do is deposit natural levees along side the main channel during floods.  These can eventually build high enough raise the bed of the river above the level of the floodplain away from the natural levees.  When this happens, the channel can shift into the lower area of the floodplain and abandon large stretches of channel.  This looks like what happened at this place in Arkansas.

I've had some edumacation in the area of fluvial geomorphology. 

That's an eloquent way to say what I was thinking happened.

So it is technically a slough?

[triplemultiplex]

So it is technically a slough?

In my pseudo-professional opinion, it is indeed a slough.