Jump to content

Recommended Posts

Missourian

My folks have a nice lake behind their house. It is relaxing to spend a warm evening watching a heron spear fish or geese fight each other. Or watch silt slowly fill the lake bed.

 

Across the street, a housing developer stripped off a bunch of soil down to the bedrock, but ran out of money before building on the land. This has resulted in some significant erosion and sedimentation in the lake, but this cloud does have a silver lining. I soon noticed a thick bed of shale exposed on the hill. So it was only a matter of time until I make the short trip to the top.

 

The hill, with exposed shale, can be seen on the right.

 

Stormy-hill.jpg

 

No, I did not hunt that day. :)

 

A few weeks ago, I drove up there and poked around the Pennsylvanian strata.

 

The Island Creek Shale is the first bed encountered:

 

Island-Creek-Shale.jpg

 

There are thin beds of calcareous sandstone within. Oh look, ripple marks:

 

Island-Creek-Ripples.jpg

 

And trace fossils:

 

Trace-1.jpg

 

Trace-2.jpg

 

I've found fusulinids and brachiopods where the shale thins several miles to the south.

Share this post


Link to post
Share on other sites
Missourian

Higher up is this oolite within the Farley Limestone:

 

Farley-Oolite.jpg

 

Myalindid pelecypods are a good marker for this bed:

 

Farley-Myalinids.jpg

 

A persistent zone of Osagia marks the upper part of the Farley:

 

Farley-Osagia.jpg

 

Osagia is basically an algae-foram coating around a grain. They formed in high-energy environments.

 

Here is a beautiful weathered joint pattern on top of the limestone:

 

Farley-Joints.jpg

 

Higher up still is the Bonner Springs Shale:

 

Bonner-Springs-Shale.jpg

 

There are a few tiny trace fossils in some thin sandstones. Several miles away, plant fossils have been found in this shale, but no luck here.

 

Moving on and up, we come to the Plattsburg Formation:

 

Plattsburg-Limestone.jpg

 

I've found sponges, crinoid calices, and even a nautiloid elsewhere in these limestones and shales, but not here. Instead, I found the usual sparse brachipods and crinoid stems.

Share this post


Link to post
Share on other sites
Missourian

Moving back down.... On top of the Farley is a jumble of limestone blocks left over from construction:

 

Block-Jumble.jpg

 

Look at all those Juresania brachiopods:

 

Juresania-Block.jpg

 

Brachiopods up close:

 

Juresania-Block-Close.jpg

 

I'm not sure where these blocks came from. I'm guessing the Plattsburg, but they are thicker than the in situ beds I could see.

 

Not too bad for a few steps from home.

Share this post


Link to post
Share on other sites
Lloyd

Good report. Loved the pictures.

Share this post


Link to post
Share on other sites
Fossildude19

Missourian,

Very good and interesting report! :)

Great pics! (That storm front looks ominously menacing!)

Thanks for posting.

Regards,

Share this post


Link to post
Share on other sites
Vordigern

great report and pics!

Share this post


Link to post
Share on other sites
Missourian

Site stratigraphy:

 

Hill-Strata.PNG

 

Units not exactly to scale.

Total section ~35-40 feet.

Share this post


Link to post
Share on other sites
Missourian

Having conquered the hill, I decided to take the low road.

 

Down-section, we come to the Cement City Limestone and underlying Quivira Shale exposed next to the subdivision lake:

 

70-Cement-City.jpg

 

The top 20% of the rock on the right was stacked in place for an artificial waterfall. Much of the lake fills an old quarry that predates me. The thin calcareous shales in the middle of the unit bear the brachiopod Kozlowskia and the occasional Caninia torquia, a large horn coral.

 

Moving down the road, we come to the Cement City and the underlying Westerville Limestone exposed in a small road cut. Some large burrows are exposed in cross section in the Cement City:

 

65-Cement-City-burrows.jpg

 

A large block of Cement City is on the other side of the road. Its underside, now facing up, is covered with large burrows. Note my toes for scale (photo taken months ago):

 

17-Cement-City-burrows.jpg

 

(Edit: this could be from the Westerville. I recently found a similar bed in that layer.)

 

The Westerville. Pinkish chert is common in this layer. I didn't spot any fossils:

 

62-Westerville.jpg

 

The road bottoms out as it crosses over the major stream of the area. From the bridge, one can just make out some rock in the stream bed.

 

Curious as I am, I made my way thirty feet or so to the bottom and encountered this:

 

10-Creek-bridge.jpg

 

The cut bank is interesting:

 

16-Winterset-glimpse.jpg

 

The alternating limestones and shales immediately told me it was the Winterset Limestone. I figured this unit was present in the area, but it still took me by surprise.

 

The thick-bedded lower part of the Winterset is also exposed, sort of:

 

13-Winterset-blocks.jpg

 

I then wondered up a small side creek, and my heart just about skipped a beat when I saw this:

 

20-Winterset-creek.jpg

 

Here before me was an extremely long cut bank into one of the premier units of the metro area, and it was so close to home.

 

Looking up close, I didn't find too many fossils, but I did spot this Pteronites ('razor clam'), possibly in growth position (just above center):

 

26-Winterset-razor-clam.jpg

 

Towards the top, the Winterset 'money bed' seemed to be present:

 

31-Winterset-cross-beds.jpg

 

This limestone is cross-bedded and is bioclastic to oolitic. An extensive molluscan fauna, including cephalopods, is found in some places, but not here. Or at least as far as I can tell....

Share this post


Link to post
Share on other sites
Missourian

A little further up, I came across more Winterset in the creek bed. The dark bluish chert is diagnostic of the unit:

 

36-Winterset-chert.jpg

 

Silicified gastropods are present, seen in the upper left and bottom center:

 

37-Winterset-gastropods.jpg

 

Moving upstream, we reach the next couple of units in the column. The top of the Winterset is near water level. The thick shale is the Fontana. The massive, tannish layer is the Block Limestone. The remainer, including the thin-bedded limestones at top, is the lower part of the Wea Shale.

 

39-Fontana-Block-Wea.jpg

 

The two limestones, a little closer:

 

43-Fontana-Block-Wea.jpg

 

A fallen block of Block shows some nice layering:

 

47-Block-layers.jpg

 

The upper part of the Block has some fossil debris:

 

46-Block-fossils.jpg

 

Continuing on, I came across another nice cut bank:

 

51-Block-Wea.jpg

 

Again, we see the Block and Wea. The limestone in the lower Wea has broken up into thin slabs. Please don't mind the coprolites :) :

 

53-Wea-slabs.jpg

 

The Wea beds are made up of fossil debris, especially the brachiopod Crurithyris (little bluish shells) and ammovertellid forams (tiny, white specks). This fauna and style of lithology is persistent over a wide area and makes for an excellent stratigraphic marker:

 

58-Wea-Crurythris-ammovertellids.jpg

 

Several feet of Wea Shale is present. I did see some limestone fragments at the top that could be Westerville, but they were too loose to be sure.

 

Further up-creek, I seemed to be entering private property, so it was time to turn around.

 

Afterwards, I drew up a stratigraphic chart of these beds:

 

Lower Beds.png

 

This little excursion taught me that just about anything can be lurking right under your nose in unexpected places.

Share this post


Link to post
Share on other sites
DeloiVarden

I think you need to publish a book on this! Great job!

Share this post


Link to post
Share on other sites
Missourian
On 11/21/2011 at 5:38 PM, DeloiVarden said:

I think you need to publish a book on this! Great job!

 

Thanks much.

 

If I did that, I'd have to bring my lazy hide back down there with a tape measure to properly do the stratigraphy.... :)

Share this post


Link to post
Share on other sites
Bullsnake

Thanks much.

If I did that, I'd have to bring my lazy hide back down there with a tape measure to properly do the stratigraphy.... :)

I'd happily assist you! :D

Share this post


Link to post
Share on other sites
Terry Dactyll

Excellent report... Really enjoyed the tour of your backyard... :)

Share this post


Link to post
Share on other sites
Missourian

This recent excursion provided an interesting detail to something that has fascinated me for a long time.

 

Since age four, I grew up about two miles to the southwest. In the creek next to my house, there was a pile of boulders oddly placed in the channel and in the banks. There were a few long, tabular limestone boulders included in the mix. We called one "Dracula's coffin." Since they were part of my world, I didn't think much of them.

Eventually, I determined the boulders were what remained of a glacial drift deposit. The rocks were obviously plucked from limestone bedrock, but I didn't know from where or how far.

 

Now just days ago, I encountered a chunk of limestone which seemed familiar. It turns out that "Dracula's coffin" is actually a piece of Block Limestone. The first image here of the Block shows another coffin-like boulder. As this cut bank and exposures along the larger creek are the only source of Block in the area, it became apparent that the ice sheets had moved from a northeasterly direction.

Share this post


Link to post
Share on other sites
Lloyd

Really nice tour of your backyard. I really enjoyed getting to see the pictures of the terrain and detail shots. I am with DeloiVarden in that you should publish a book on this. Give you another excuse for a walk in the wilderness as you take detailed measurements of the strata <just in case you need one...>.

Share this post


Link to post
Share on other sites
Missourian

For me, 50 degrees and sunny means one thing: fossil hunting and photographing outcroppings (well, two things....). This time, I checked up on some road cuts about two miles from home.

 

Two of these cuts expose the sequence of layers that lies between the Cement City Limestone and the Island Creek Shale (shown earlier in this thread).

 

The Chanute Formation is a fairly thick bed of shale with some marine sandstones in the middle:

 

18-Chanute-slope.jpg

 

The sandstone is only moderately developed here.

 

19-Chanute-sandstone.jpg

 

At a creek exposure (now covered over) near my childhood home, the sandstones had trace fossils and some amazing ripple marks:

 

03-Chanute-ripples.jpg

 

These ripples indicate a near-shore environment with wave action.

 

At another exposure across town, the Chanute produces abundant gastropods:

 

20-Chanute-gastropods.jpg

 

I will revisit that spot some day.

 

The next unit up is the Iola Formation, part of which can be seen in the Chanute photo above.

 

The Iola is made up of the single-bed Paola Limestone, the black, platy Muncie Creek Shale, and the Raytown Limestone:

 

12-Iola-full.jpg

 

The Paola and Muncie Creek, at bottom:

 

10-Iola-lower.jpg

 

I've found a few fossil-bearing phosphatic concretions in the Muncie Creek here before, but not today. Here are a few examples (from many localities):

 

19-Muncie-Creek-nodules.jpg

 

Above the Muncie Creek, the Raytown starts out with a persistent crinoidal bed. This is separated from the overlying limestone by a thin shale. These beds in the lower part of the Raytown, along with the Paola and Muncie Creek, are distinctive in appearance, and can be helpful when spotting the formation from afar.

 

The Raytown is known for its abundant Archaeolithophyllum, which is a calcareous red algae:

 

17-Raytown-algae.jpg

 

This algae gives the rock a mottled appearance, which led to old-time quarrymen naming the Raytown 'Calico Rock'.

Share this post


Link to post
Share on other sites
Missourian

Towards the top of the limestone, the algae decreases, and large productid brachiopods appear:

 

15-Raytown-upper.jpg

 

The upper surface of the Raytown contains many productids. In the center, a trail trace can be seen:

 

08-Raytown-brachs-trail.jpg

 

Shark teeth are occasionally found on this bedding surface.

 

The Raytown often displays a prominent joint pattern:

 

07-Raytown-top.jpg

 

The next unit up is the Liberty Memorial Shale:

 

20-Liberty-Memorial-slope.jpg

 

Ironstone concretions are often present in this formation. They make a good marker for the bed:

 

02-Liberty-Memorial-siderite.jpg

 

However, the Wea Shale also produces these concretions in a few places.

 

Higher up in the Liberty Memorial, there are a few thin beds of limestone made up of mollusk debris:

 

03-Liberty-Memorial-coquina-field.jpg

 

Here is a slab of this coquina, collected earlier and washed off at home:

 

07-Liberty-Memorial-coquina.jpg

 

Mollusks include bellerophontid gastropods and various pelecypods.

 

Those are nice, but the Liberty Memorial (formerly Lane Shale) is famous for its crinoids. Several years ago, at this exposure, I found a 'nest' of calices and partial crowns near the base of the shale. Most of them are here:

 

11-Liberty-Memorial-crinoids.jpg

 

These beds represent a classic 'Kansas cyclothem'. According to theory, these cyclothems were caused by successive glaciations that covered the southern reaches of the Pangaea supercontinent. In this setting, which was on the equator at the time, thick shales like the Chanute and Liberty Memorial represent periods of glaciation, when water was locked up in the ice cap. The limestones and black shales formed during the interglacials.

 

The near-shore to non-marine Chanute transitioned to the Paola as the sea covered the area and deepened. At maximum depth, water circulation became poor. Carbonate production ceased as the conditions became anoxic. This is where the Muncie Creek comes in. Fossils in this black shale include pelagic creatures that sank to the bottom after death. They can include conodonts, fish, shrimp, and ammonoids, among other things. Once the sea began to drop back down, limestone production resumed. The Raytown is thicker than the Paola because the ice takes longer to build up than to melt away. As the sea level dropped further, the Liberty Memorial Shale formed as muddy deltas began to spread across the carbonate sea floor. In many of these thick shale deposits, coal beds formed where vegetation covered the land.

Share this post


Link to post
Share on other sites
jpc

Nice report... any chance we could see some close-ups of those phosphatic nodules? What are the fossils in there... looks intriguing.

Share this post


Link to post
Share on other sites
Roz

Yes, I would like to know too. I see some that are fossils but I

don't know what they are.. Gotta love the nodules when they

are generous.. :)

Share this post


Link to post
Share on other sites
Missourian

The nodules shown here include conularids, ammonoids (Proudenites), phyllocarid telsons and a carapace (Concavicaris), a possible shrimp tail (fly-like structure) and miscellaneous chitinous material, various fish bones and a tooth, and coprolites (some with fish bones and scales).

 

I'll try to get some closer pictures.

 

These are examples of run-of-the-mill Muncie Creek. Eventually, I'll pull some better specimens from my 'top drawer'. :)

Share this post


Link to post
Share on other sites
Missourian

Moving on and up, we encounter the next marine incursion, the Wyandotte Formation. It can be seen here above the Raytown and Liberty Memorial:

 

22-Argentine-above-Iola.jpg

 

The Wyandotte is made up of the Frisbie Limestone, the Quindaro Shale, and the Argentine Limestone. Because the bottom part of the formation is covered here, I was unable to distinguish the Frisbie and Quindaro from the Argentine.

 

Like the Raytown in the Iola, the Argentine is by far the thickest unit in the formation.

 

The Argentine is prominently exposed in the northern and western parts of the Kansas City Area. It can often be recognized by its light buff color and its series of relatively thin, regularly spaced, wavy beds:

 

28-Argentine-beds.jpg

 

Normally, large, white productid brachiopods can be found in the lower beds. I didn't spot any here, so the base of the Argentine is probably covered as well.

 

Brachiopods are present throughout the formation. On this bed, three types can be seen. They are Composita, Juresania, and Neospirifer. Can you spot them?:

 

29-Argentine-brachiopods.jpg

 

More brachiopods, as well as some phylloid algae, are visible on this weathered joint surface. The hammer points to a Punctospirifer:

 

32-Argentine-algae-brachs.jpg

 

At a nearby exposure, we have an opportunity to view a bioclastic limestone that caps the Argentine. It is the massive bed at top:

 

34-Argentine-bioclastic.jpg

 

It is made up of finely fragmented shells and crinoid ossicles:

 

37-Argentine-bioclastic-close.jpg

 

Note the subtle cross-bedding. These drifts formed in shallow, agitated water.

 

South of the metro area, about 50 miles from home, the Wyandotte and the overlying Farley Limestone combine and swell into a massive algal reef. The units are up to 100 feet thick in places. Continuing south, the beds soon pinch out, leaving nothing but a combined Liberty Memorial-Bonner Springs shale.

 

For Texas Pennsylvanian fans, the geology of the reef and surrounding strata is somewhat similar to the Graford Formation near Lake Bridgeport.

The next unit up is the Island Creek Shale, but it is covered or missing here.

 

And finally, the stratigraphy of the three road cuts:

 

Middle layers.png

Share this post


Link to post
Share on other sites
Kehbe

Missourian,

I can't thank you enough for explaining and showing excellent examples with your photography of the stratigraphy of the areas locally around here as I am trying very hard to learn and I'll tell you, my brain don't work quite like it used to so it's been a challenge. Probably all that clean living I've done over the years! Your "tours" have helped me tremendously and your explanations and descriptions are understandable for an average Joe such as myself! I just wanted you to know your time and effort in posting all this information is much appreciated by noobs like me! Thanks again! Since we are neighbors, I would love to maybe get out there in the field with you sometime and learn just a fraction of what you know! Maybe next spring!

Share this post


Link to post
Share on other sites
Missourian

I'm glad I can help others in the metro.

 

I've recently gotten back into fossiling after a long hiatus. Scrambling all over these outcroppings, imaging them, and studying the photos has reacquainted me with these formations. :)

Share this post


Link to post
Share on other sites
Missourian

Moving a couple miles down the road, we revisit the Bonner Springs Shale and the Plattsburg Formation. As you may recall, these lie above the Island Creek Shale and the Farley Limestone, which in turn lie above the Argentine.

 

(For the record, the Island Creek, Farley, and Bonner Springs make up the Lane Formation.)

 

At and near a highway interchange, there are impressive exposures of these strata. We start off with the Bonner Shale at an adjacent construction site:

 

61-Bonner-Springs-shale.jpg

 

Here, we can make out the contact with the overlying limestones of the Plattsburg. The sediments display some nice color and small-scale bedding.

 

This claystone takes on an intense green color when wet:

 

53-Bonner-green-mud.jpg

 

There is some interesting mottling in this chunk of the claystone:

 

56-Bonner-splotches.jpg

 

About a month ago I collected a couple chunks from this exposure. This chunk of finely laminated sand and mud shows some nice detail. It came from a bed below the claystone:

 

83-Bonner-laminae.jpg

 

The only fossils present in the Bonner Springs that I could see are these traces in some of the sandstone:

 

59-Bonner-traces.jpg

 

Only the lower Plattsburg is preserved here. For a full exposure, we move back over to the highway ramps. Here, at the west ramp, we can view an impressive, 30-foot exposure of the lower Lansing Group:

 

62-Lower-Lansing.jpg

 

Though the Bonner Springs is covered with weeds, we can make out the entire Plattsburg Formation, most of which is Spring Hill Limestone. The Vilas Formation and the Captain Creek Limestone of the Stanton Formation appear as thin units in the top.

 

Over on the east ramp, the strata of the lower Plattsburg are beautifully exposed:

 

44-Lower-Plattsburg.jpg

 

The Merriam Limestone and the lower Spring Hill are separated by the Hickory Creek Shale, which is the prominent shale bed below the tan rock. The Hickory Creek contains crinoids and sponges in places. Since I'd just identified the unit in these exposures, I will have to go back for a closer look.

 

Here, a little weathering of the Spring Hill has enhanced the bedding. Note the chert near the top and the layer with protruding nodules:

 

45-Spring-Hill-Weathered.jpg

 

The nodules up close:

 

46-Spring-Hill-nodules.jpg

 

These may be algal structures rather than concretions, but I'm not quite sure at this point.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Recently Browsing   0 members

    No registered users viewing this page.

×