But if the earth is only 8 to 10,000 years old...why is the age of speleothems important? Does dating them prove that the cave existed before creation?
Geary Schindel wrote: > Mark, > > Maybe one of the specialists in this area > will respond with more detailed information but yes, speleothems can be dated > by > analyzing the ratios of radioactive elements. They do have growth rings > but the ones you see with the naked eye do not equate to dates like tree > rings – > it is a lot more complicated than that. In the past, ice cores have been > used to determine atmospheric gas composition and estimates about climate > back to approximately 100,000 years. I understand that the speleothem > dating techniques can take the dating back almost 400,000 years with > surprisingly > good resolution (20+ years?) and are now becoming the gold standard for age > dating and climate studies with microcrystalline growth rings being used to > estimate regional rainfall. It is also much complicated than I’ve > described. Speleothems have the added advantage in that they occur almost > anywhere there are caves so therefore, you can create a local data base of > dates rather then depending upon ice cores which can only be obtained from > high > mountains or the Polar Regions . Dating of speleothems used to be a pretty > arcane practice > done by very few geologists/speleologists who were looking to answer specific > questions such as whether speleothems continued to grow during ice ages which > would imply that the area above the cave was ice free or to try and determine > a > relative minimum age for a cave passage. The techniques have become more > refined and speleothems have now a hot field of study and have become a > critical > piece of data to understand global climate change. > > Generally, the speleothem is cut in half > and rock specimens are removed along the axis of the speleothem and analyzed > for their uranium thorium content through a process which involves a lot of > complex chemistry using some fairly strong acids (needless to say, you can’t > do this at home with your rock tumbler). > > Regarding your comment about whether speleothems > should be removed for use in scientific interest. Well that depends – > most scientists are very responsible about the removal of speleothems and > would > not recommend that prominent formations be removed and if a specimen needed to > be collected, that it be done so to minimize the impacts to a cave. > Removal should also only occur with permission of the owner. Cave > formations are very nice to look at and the indiscriminate destruction of > formations should certainly be discouraged. However, the removal of a few > formations for scientific use is considered by many scientists to be > acceptable. > > Note that cave sediments can also be used > for relative age dating and should not needlessly be disturbed, not only does > an undisturbed floor look nice but the sediments may provide some important > scientific > data. > > Formations have been removed from a number > of caves in Texas including Devils Sinkhole. The UT Geosciences Department > has > one of the better labs in the country and has published their results in a > number of scientific publications. > > Geary > > -----Original Message----- > From: [email protected] > [mailto:[email protected]] > Sent: Wednesday, January 23, 2008 > 12:27 PM > To: Allan Cobb; Texascavers > Mailing List > Subject: RE: [Texascavers] Caving > Show on Discovery Channel > > Did anyone happen to > watch this show the other night? > > > Were you as horrified as > I was when the overly dramatic host and another scientist took a chisel to an > ~ > 3 foot by 4 inch stalagmite in order to break it free in order to count the > rings? > > Apparently, they were > wanting to calculate the rate of annual water flow in order to match it up to > the apparent demise of the below mentioned headless skeleton. > > Their theory was that the > hapless victim was sacrificed at about the same time as a drought was > occurring > and, by doing so, the gods would be pleased with the sacrifice and send rain. > > How you could correlate > the age of the stalag with the victim's death is beyond me. > > Is this appropriate > behavior? > > I'm surprise no one else > hear saw this or thought to comment on it. > > > Y'all's thoughts? > > > Mark A. > > > > From: Allan Cobb [mailto:[email protected]] > Sent: Sunday, January 20, 2008 > 10:58 PM > To: Texascavers Mailing List > Subject: [Texascavers] Caving Show > on Discovery Channel > Monday night (January 21) at 8 PM is > a new series called Bone Detectives. This episode is about a headless skeleton > in a cave in Belize. The cave that the show centers around is called > Midnight Terror and it was only discovered about a year ago. The show > also did filming in several other caves in Belize. --------------------------------------------------------------------- Visit our website: http://texascavers.com To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
