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s'. .l ~'.:. :'~.~ • ... ~111L1 LLLIL L `!' ~4 LW U LVJ~L~ V9 ~~LVJo ~OUTE 2, BOX 21 E • • LAMPASAS, TEXAS 16550 • PHONE 512 / 556-2301 April 11, 1981 Gordon C. Tucker, Jr. Departrre rt of Anthropology university of Colorado Boulder, Colorado 80309 Dear Gordon: In rep ].y to the questions ,you asked concerning the s.~nPles I ran far "•~rrl. Nickens, here are my comments. My initial estimation of the charcoa] i~r the samples was that it xas nicA, although in general there was consi~i~~rahl.~~ dirt in association with it. The amount of charcoal in two of i,h? sam:~lus xas quite small, yielding only about 1/3 as march CC2 £or analysis as I normally use. This will result in a larger uncertainty for the date, pis is seen for RL-11127 and RL-1430, but is not real ly a.factor repardinl; your problem, IS RL-1430 had been full-sued, it would roost likely still be designated as Modern.. • All the samples received my standard pre-treatment xhich is a hot bath in dilute HC1 to remove any carbonates present, followed by washing and drying. I sometimes x111 employ a dilute Na011 bath to remove possible humic acids contamination, but based on the nice, dry apprarance of the charcoal, and the small amount in several of, the samples, I did not deem this treatment necessary or xis e. Your suggestion of contamination by surface root burn xould seem to havr. some validity for txo of the samples, RL-1426 and RI~11r29, inasmuch as there xas so much rootlet material which I co~rld not separate by my usual methods, I resorted to picking out the charcoal for the burning with forceps, I have left-over material from several of the samples, xhich I have looked at since receiving ,your letter; the material from RL-1lr26 is loaded with charred rootlets annroaching 1 mm in diameter, These rootlets look to be as much charred (and therefore as mm h a part of the sample) as the "bona fide" charcoal, and I may have incorporated some of these in with the burning, Ttris points up the need (often neglected) for the submittor of a sample to screen it and remove, or indicate for removal, ambiguo~rs material. Sven if I did burn some of these rootlets, aM thry were Modern; that, contribution would not be enough to eau..^,e an otherwise Paleo-Indian date to be 14odern, or close to Modern. 1 donut kno•,r what date Paloo-Indian refers to, but I'll a:~sume its about 2W0 A,P. If the sample i h~~rnnd contained half rootlets by weight (which is hiP,hl;~ unlikely}, the resulting . age of the sample would be 1000 A.P. Only if th? rootlets were contemporary with the nuclear bomb testing days could an archaeological sample be ca~rsPd to appear Modern.