Ezell's Cave is another place where thick sheets of calcite ice seem to form very quickly. A beautiful thing to dive under, like giant snowflakes mixed with saucer sized chunks of "ice"raining down from above.
Andrew G. Gluesenkamp, Ph.D. 700 Billie Brooks Drive Driftwood, Texas 78619 (512) 799-1095 a...@gluesenkamp.com --- On Mon, 2/13/12, Mark Minton <mmin...@caver.net> wrote: From: Mark Minton <mmin...@caver.net> Subject: RE: [Texascavers] Honey Creek sand observation To: texascavers@texascavers.com Date: Monday, February 13, 2012, 7:45 PM In a similar vein, back in the '80s in Spring Creek Cave (TX) I remember breaking through calcite ice that had formed a solid layer on the surface of the water in active stream passage. We crunched through it sinking large pieces as we walked. A few months later when we returned the solid layer of calcite had already reformed on the water. I do not remember the times of year that those trips took place, but obviously calcite rafts/ice can form very rapidly under optimal conditions. Mark At 04:36 PM 2/13/2012, George Veni wrote: >I've been thinking a lot about Snowy, and its situation is different from >Honey Creek. Calcite precipitation on the floor of Honey Creek occurs mostly >by sunken rafts, whereas calcite in Snowy is precipitated as a crystalline >layer on the submerged walls and floors. The basic geochemical equations and >processes are the same, but there are some important differences that affect >the methods of deposition. I've not seen any water chemistry data for Snowy >and no such data exists for how the water evolves as it flows down the >passage. Also missing, at least to my eyes, is information on carbon dioxide >in the air and water at Snowy. Lastly, the source area for Honey Creek's >water is fairly well understood, which is not the case for Snowy. > >I'm not discouraging research, only pointing out how much more needs to be >done. So much karst. So little time... > >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 > >-----Original Message----- >From: Pete Lindsley [mailto:caverp...@gmail.com] >Sent: Monday, February 13, 2012 13:26 >To: gv...@nckri.org >Cc: 'texas cavers' >Subject: Re: [Texascavers] Honey Creek sand observation > >George, it would also be interesting to relate this to the development of >the rather recent calcite formation in Snowy RIver. SR only forms calcite in >SR during a "flood event" in the really dry NM area, and that apparently >happens only 2-4 times in a 10 year period due mostly to heavy rains and >heavy snow melts. > >So we have two "Laboratory Caves" here, one in dry NM, and the other in a >much wetter TX area. > > - Pete > >On Feb 13, 2012, at 1:17 PM, George Veni wrote: > >Measurements I made of soil and cave air carbon dioxide during my >dissertation research in the Honey Creek area show a strong positive >correlation between spring-summer plant growth and increases in cave air >carbon dioxide. Studies in other areas have shown the same thing. > >You are correct that the water temperature has an effect, as do seasonal >changes in water chemistry, both of which I didn't mention for the sake of >brevity. I would expect that a decrease in temperature would result in >dissolution of the rafts rather than the precipitation we see. However, >because the water temperature has usually come close to equilibrating with >the temperature of the surrounding mass of rock and water by the time we see >it in the areas where rafts are deposited, I would also expect any >temperature effects to be minor given the small decrease in temperature. I >have measured significant changes in carbon dioxide and know that is >certainly a major factor. > >It would be interesting to run a "standard" example of the cave's water >chemistry values through a geochemical model and tweak the temperature and >carbon dioxide levels over a series of iterations to predict how much of a >change in temperature or carbon dioxide would be needed to affect raft >deposition one way or the other. > >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 > >-----Original Message----- >From: Diana Tomchick [mailto:diana.tomch...@utsouthwestern.edu] >Sent: Monday, February 13, 2012 12:40 >To: <gv...@nckri.org> >Cc: texas cavers >Subject: Re: [Texascavers] Honey Creek sand observation > > > 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. > >Does the cave atmosphere have less carbon dioxide due to lesser amounts of >degradation of biomass in the ground over the cave in the winter (due to the >lower surface air temperatures), or is it due to a reduction in temperature >of the creek water in the cave? Because the solubility of carbon dioxide >increases as the temperature of water decreases. > >Diana Please reply to mmin...@caver.net Permanent email address is mmin...@illinoisalumni.org --------------------------------------------------------------------- Visit our website: http://texascavers.com To unsubscribe, e-mail: texascavers-unsubscr...@texascavers.com For additional commands, e-mail: texascavers-h...@texascavers.com
