In Guatemala, I have seen calcite almost completely covering flagging tape that we left surveying the year before. I have seen stalagmites about 50 cm tall growing out of Maya vessels that are a little more than a thousand years old. I have seen photos of one almost a meter high growing out of a 1000 year old Maya vessel. The growth rate of speleothems is highly variable.
Allan From: Neal Hines Sent: Tuesday, March 12, 2013 11:33 AM To: nealahi...@gmail.com Cc: Texas Cavers Subject: [Texascavers] Estimate of stalactite growth (Merkel et al. 2008) This morning I read a geochemistry text on carbonate mineralization that gave an example of how much stalactites might grow in one year: 0.19 mm/year. It's a recent book (Merkel et al. Groundwater Geochemistry 2008). Assumptions: partial pressure CO2 of 3% (charged up from soils) degassing to 0.03% (by volume; atmospheric level), 100L of water dripping from the ceiling, and the ceiling covered by 15% stalactites. Cavers all know this growth varies by quite a bit, but this might serve as a rough upper end growth rate. So, within a caver's life of 70 years, you could see a formation grow by over 1 cm! Lending truth to the observation I've heard of some cavers that, "this passage has shifted since I was here last." Sodastraws can grow even faster I believe & I'm sure people will have opinions on that. Also, thanks to Ron Green for doing the webinar on Geophysics in karst landscapes last night. I caught only the tail end, but there were tons of questions and very interested participants. -Neal Hines
