Carroll Cave Conservancy




2 0 0 7   C A V I N G




10/15/06 - installing the first data logger (Gee)
Elec. Resistivity Survey by Davis
Evaluation of the Carroll Cave Area Hydrogeologic Data Base
Geological Analysis by Morris Hall
Remote Sensing Data by Morris Hall
Geology of Carroll Cave by James A. Helwig
Whirllpool Sink
Earth Sciences Plan
Preliminary Sinkhole Analysis - Montreal 7
Preliminary Hydrochemistry Intrerpretation of Carroll Cave

2003 Summary of Activities for the Geology Project

The hydrogeology effort is being directed towards answering a number of issues concerning the Carroll Cave System. To support the study, water samples are being collected and evaluated for parts of the cave to determine water quality and chemical characteristics. This study will help determine the origins of the groundwaters in Carroll and potential location of new passageways in the cave system.

The second effort is a sinkhole location study. This effort is being led by Jeff Page.

The principal effort last year was the creation of a GIS data base for hydrogeologic data.

A presentation on Carroll Cave hydrogeology was made at the annual NSS convention by Morris Hall.

Morris Hall plans to talk at NSS convention.  His abstract is pasted below.


A multidisciplinary approach is currently being used to characterize the Carroll Cave System. Mapping of surface karst and geologic - hydrologic studies in Carroll is helping direct current exploration and surveying efforts.  The examination of rock samples and 9 thin-sections from the new entrance borehole of Carroll places the majority of cave in the lower Gasconade Formation of Ordovician age.  The cavern's development has been strongly influenced by structural deformation of lower Gasconade strata. Groundwater flow follows dip of geologic structure in the Upper Thunder River and Carroll River passageways, but trends along strike of geologic structure in the lower Thunder River passage. Analysis of groundwater samples taken from various locations in the cave indicate a change in dissolved mineral saturations that may help explain the caves' development.  Inorganic water quality of the cave is excellent. Flow and chemical analysis of groundwater points to ex! tensive, unentered portions of cave. Overburden and sinkhole location maps are used to infer possible boundaries and extensions of the cave system.  A surface temperature survey and characterization of a sinkhole collapse has led to an interpretation of a significant extension of the cave towards Barnett Hollow 6400 feet west of Carroll passageways. Several sinkhole valleys filled with alluvial gravels, that may support recharge to Toronto Springs, have been identified.  The validation of computer geologic mapping is currently ongoing with 30 sinkholes out of hundreds field-located and photographed.




From: "Jerry Vineyard" <>

Date: Tue, 22 Apr 2003 10:49:29 -0500

Listen to Jo, folks! After quite a struggle, we finally have an honest-to-goodness Speleology Section of the Missouri Academy of Science.  Last Saturday's session had only three papers, but what a future was laid out for all to see! Consider:

1) A new generation of caver-scientists is being educated as we speak, not only to appreciate caves for what they are and what they contain, but also to become caring conservationists,

dedicated to insuring that caves have a meaningful future. This is greatly different from my generation, when it would have been "career-suicide" to say, "I'm going to be a speleologist."

2) REAL MONEY is being spent on gating caves and saving endangered cave species. And

the best news is that animals that were once on the brink of being extirpated (big word for "wiped out") are returning in significant numbers. Of course that also means that cavers have to be more respectful of the space that such animals need to survive, but that is small price to pay for helping to save amazing little critters that are indispensable in the natural world.

3) Carroll Cave is BACK! I know this really isn't news anymore, but Morris Hall laid out the evidence for what a great cave Carroll can become, now that it is once again accessible to cavers. It was utterly fascinating to see the hydrogeology of the system laid out in full living color, and to understand the scientific basis on which the predictions of a great cave are based. After this presentation, we went away BELIEVING that Carroll will one day have maybe 40 miles of mapped passages, and if it's possible to push into adjacent drainages, all bets are off as to how long it may become!

It was nearly 50 years ago (1956, as I recall) when Oz Hawksley first led us into Carroll Cave, and it was wonderful to see him again as a new era of Carroll's history unfolds. BTW, next year's Academy mtg. will be in Kansas City, in late April. Stay tuned for more news.

Jerry Vineyard


Articles about the geology of Carroll Cave are being accepted for publication on this website.  James Helwig published a paper based on his undergraduate thesis (St. Louis University, 1963) in the NSS Bulletin in 1965.  The papers by Morris Hall are being developed currently (2002).  Mr. Hall is a professional (petroleum) geologist and past member of the Lake Ozark Grotto (1970's).  He has maintained his interest in the cave over the years and also submitted the following letter.


(received July 12, 2002)

Very nice to have met you and the other caver diggers...the geology of the cave is very well described in the report by Helwig, (NSS Bulletin Volume 27, Number 1, January 1965) and is way ahead of it's time in terms of cave genesis thought and basic geologic reasoning... the description of the geology of the Gasconade, amazingly enough, is quite limited.


The entrance shaft provides a rare opportunity to describe the upper Gasconade along a significant, fresh exposure and will be important both from a geologic and hydrologic perspective. Not only does the shaft provide rocks for analysis, but water samples taken at the various entrance points along the shaft will provide insight into the vertical profile of water chemistry, ph, solution potential, etc. that when compared with the cave's hydrology, might give some valuable insight into the creation of the monster we know as Carroll.


Looking back briefly over the topo map, the cave will definitely extend westward to the plateau sinks south of Montreal...the intriguing idea is presented by the sink that you describe and showed that would be north of the left (D6-7) passageway in lower Thunder River. That would suggest a significant portion of the cave system could exist N and NW of the present cave.


The rarity of Carroll is because of several factors:

  1. Significant thickness of soluble rock (300' Gasconade dolomite).

  2. Bed boundaries (bedding planes) providing horizontal paths for solution (Ordovician)

  3. In-situ and tectonic fractures of both Ordovician and Pennsylvanian age creating vertical areas of weakness

  4. Climate -40 " rainfall per year...

  5. Temp.-56 favorable for dolomite dissolution

  6. Vegetation- lowers rainfall's ph and helps in creation of carbonic acid

  7. Ozark uplift- creation of drainage of phreatic conditions to primarily vadose conditions ( not a severe tectonic event...)

  8. Large potential drainage area of Toronto Spring watershed.  Chemical equilibria analysis of Toronto Springs suggests that the effluent is still capable of dissolving lots of rock (i.e.) the groundwater is under saturated with respect to calcite and dolomite. A very simple analysis....1MMGal/day lower thunder river = app.20 miles of cave....where is the cave system that contains the other 3MMGal/day ? (where is the other 60+ miles of cave?). Probably allot of it is water-filled (i.e. below the level of the siphon), but the chemical analysis suggests that allot is air-filled...

(received 10/4/02 from Morris Hall)

Thin sections have been received...very interesting..the left photo is at 55' showing a quartz sandstone, with well rounded grains and a clay matrix...glauconite is present in trace amounts.  10% porosity this is the Roubidoux formation. the second photomicrograph at 75' is a medium grained, surcosic dolomite showing non-uniform euhedral crystal fomation...little calcite present.  20% porosity..this is the upper Gaconade...some relic texture is visible...other slides show replacement chert where the chert replaces fossil fragments..maybe the lower Gasconade contact....neat stuff.. we spent $180 on 9 samples...the shaft photos will help nail it down but..

0-9' Soil, weathered Roubidoux

9'-55+' Roubidoux

55+'-100' Upper Gasconade

100'-Total depth Lower Gasconade

Upper Gasconade is approximately 45' thick

we may need 4 to 5 additional thin sections...