Calcite sand in Honey Creek is usually deposited due to turbulence related to both normal and flooding conditions.
Kurt described deposition common to normal conditions: . Dripping water sinks floating calcite rafts; . Rafts accumulate on the upstream side of dams, where as more accumulate they become more sensitive to disturbances in flow and thus sink there; . Rafts accumulate below dams where they have washed over the dams and get sunk on the downstream side. Andy described deposition common to flooding conditions: . A "bathtub ring" of calcite coats the walls as water levels rise and later fall, draping the calcite rafts on the walls; . Calcite accumulates below areas that would be especially turbulent during high flows, causing floating rafts to be sluiced along and concentrated in areas where they sink. The degree to which the sand accumulates or is noticed at any given time depends mostly on: . How much time has passed since the last flood, which determines how many rafts will accumulate floating on the water; . How severe the flood was, and did it just sink the floating rafts where they can be seen, or wash them away or bury them under silt and clay where they will not be seen; . The chemistry of the cave's water and atmosphere to create favorable conditions for raft development. Kurt is right that they usually form more quickly in the winter because the cave atmosphere has less carbon dioxide at that time, allowing more carbon dioxide to degas from the water, driving the water to supersaturation with respect to calcite, and promoting calcite raft development. George *************************** George Veni, Ph.D. Executive Director National Cave and Karst Research Institute 400-1 Cascades Avenue Carlsbad, New Mexico 88220-6215 USA Office: 575-887-5517 Mobile: 210-863-5919 Fax: 575-887-5523 gv...@nckri.org www.nckri.org From: Andy Gluesenkamp [mailto:andrew_gluesenk...@yahoo.com] Sent: Monday, February 13, 2012 11:00 To: texas cavers Subject: [Texascavers] Honey Creek sand observation This was different. First, I noticed small areas of white sand in pools in the spring run. There were some now-dryish pools that had a coating of "sand" on the bottom (but on top of the mud), as if they were filled during the "high tide". We also noticed a 3/4-inch wide band of fine white sand on top of the mud layer on walls about a foot above the water line (high tide line?) along passage near WM. Also, areas where the floor dropped off were covered in fresh white sand (sand over mud). We meant to collect a sample for later "fizz" testing but, alas, the urge to splurge on Philly cheese steaks and beer was too great for our group and we plumb forgot. Andy Andrew G. Gluesenkamp, Ph.D. 700 Billie Brooks Drive Driftwood, Texas 78619 (512) 799-1095 a...@gluesenkamp.com
