An intrepid crew of more than 15 cavers descended on Cherney Maribel Caves County Park on a cold, windy Saturday in early April, 2004 for a cave dig. Most of the diggers worked on New Hope Cave, removing sediment from the Halloween room on the way down to the original cave floor. In the past, work in this area had been slowed by the necessity of carrying buckets of dirt out through a low stoop-walking passage to the cave entrance. For this dig, Kasey brought ten sections of roller tracks which were set up in the passageway, allowing the buckets to be placed on boards or plastic sled dig trays and rolled out of the cave. With helpers stationed at the turns in the passage, the trays could quickly be sent out of the cave, the buckets taken off, and empty buckets sent back in. Once this sytem was set up and fine tuned, even our energetic teenaged diggers were hard-pressed to keep up with the flow of dirt out of the cave. Outside the cave, the bucket brigade used the sand to fill in and level the pit outside the cave entrance.

Dig tray at the loading station

A dig tray enroute to the cave entrance

As the afternoon wore on, the Halloween room got larger and larger, eventually having plenty of standing headroom for the entire crew. With the sand level going down, some of the rock which had seemed to be a solid barrier was found to be fractured and loose, so a few strategic probes with a prybar brought the worst of the rock down. This broken rock was sent out in buckets on the dig tray, enlarging the room even more.

As material was excavated from the room, a "stratigraphic column" (right) of the sediments was revealed. The lower levels were filled with hundreds of slanting layers of coarse sand in alternating light and dark bands. Higher up, these layers were cut off at an angle and overlaid with a single band several inches thick made up of coarse gravel and stones up to a few inches in size. Above the gravel bed, the sediment seems to be fine sand and silt. The upper layer of sediment is capped with a flowstone crust throughout most of the cave.

Bearing in mind that the writer is neither a geologist, hydrologist, or speleologist, here is one off-the-cuff analysis of the deposition of these sediments:
New Hope Cave was probably formed sometime before the last advance of the glaciers. When the last of the glaciers retreated, a vigorous flow of melt water carried a fairly steady stream of coarse sediment into the cave from an entrance farther up. (Note that there are a number of sinks and a disappearing stream about a mile west of the cave.) Seasonal variations in flow - slower in winter, higher in spring and summer - probably accounted for the layered aspect of these sediments. After perhaps hundreds of years of steady accumulation, some dramatic event, such as the breaching of a natural dam, caused a high-energy flow of water through the cave, eroding the existing layers of sand and carrying in much coarser gravel & pebbles. After this event had altered the hydrology of the area, the flow of water through the cave seems to have been reduced, and carried in only fine sand and silt. Eventually the upstream entrance to the cave became plugged, and flow through the cave stopped. Water did continue to percolate into the cave through the overlying calcium-rich dolostone, forming the speleothems decorating the cave today, and depositing the flowstone crust which comprises the current floor of the cave.

The stratigraphic column of sediments in New Hope Cave could yield important information on a couple of fronts - it could help to explain the prehistoric formation of Wisconsin's post-glacial landscape, and by studying the direction of the sediment bedding, it could point the way to the original upstream source of the cave.

The following weekend Kasey & J.D. returned to New Hope Cave and really got the track system working. By leveling and securely fastening the track sections together and straightening the runs, they were able to make it possible for a two-person team to do an effective dig in the cave. One digger loads the dig tray, the other pulls it out with a rope and empties the tray, then the inside guy pulls it back in and repeats the process. The tray even goes around corners by itself on the roller track!

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