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

 

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