When has the woolly mammoth lived in North America and Eurasia? When has it died out? How many years ago? Geologist say, the woolly mammoth has lived during the late Pleistocene time. And it has died out at the end of the late Pleistocene, at the beginning of the Holocene time. They are basing their geological time-scale about the late Pleistocene-Holocene period mainly on radiocarbon dating. These dates they have measured on the remains of plants and animals, and the sediments of lakes and ponds in deglaciated areas. This Late Pleistocene time-scale geologists are using now throughout the world. – But how reliable are these radiocarbon dates, done on the remains of the woolly mammoth, on wood and on soil from this time? How trustworthy are they?
Radiocarbon dating they have also done on Californian Paleo-Indian skeletons. First they were dated as late Pleistocene. Then as Holocene. Also bone tools, like the famous Old Crow flesher from the Northern Yukon, they have radiocarbon dated. At first, the radiocarbon dates on tools made from bones by Paleo-Indians in the Northern Yukon Territory were supposed to be of late Pleistocene Age. They were said to be 26,000 years old. Then they tested them again. Now they are only 1359 years old. They are of Holocene Age (Nelson, D. E. et al. 1986:749, 750).
The radiocarbon dates from Lake Manitoba, Eastern Canada, have also become quite famous. Old carbon is mixed up there with new carbon. The radiocarbon error is there up to more than 25,000 years (Nambudiri, E.M.V. et al. 1980:125). Dating meltwater sediments in deglaciated areas is also not reliable The dates are too old. (D. G. Sutherland, 1980:142-148). There are problems in dating sediments. "... no one molecular fraction or pretreatment protocol will guarantee the accuracy of a 14C measurement." T. W. Stafford et al. (1991:161).
Collagen Dating
Collagen is a protein also found in the bone. The bone, buried in the ground, or lying on the surface, is leached more and more by water. Its proteins are broken down more and more and are seeping out. The empty space in the leached bone is filled up then by foreign molecules and atoms, oozing into it from the surrounding soil-water. – How fast is the bone leached by water at which temperature?
P. E. Hare, Geophysical Laboratory, Carnegie Institution of Washington, Washington, D.C., reports about his finding under the heading, "Organic geochemistry of bone and its relation to the survival of bone in the natural environment": "Unlike modern bone, fossil bone shows extreme variations in amino acid composition. In general, for a constant environment, the older the fossil bone the less organic matrix it contains and consequently the fewer total amino acid residues per gram of bone. The relative amino acid composition also shows extreme variations, ranging from collagen-like patterns to non-collagen amino-acid patterns." (1980:209).
"In most natural environments, however, water is present in excess, at least periodically, and this results in the leaching of soluble components. To simulate the possible effect, bone samples were heated in various amounts of water. In one series of experiments the surrounding water was changed frequently so that the bone fragments were in contact with fresh water most of the time. The simulated diagenetic changes resulting from the bone-heating experiment varied dramatically according to whether or not water was present and how much. ... The sample heated under anhydrous (= no water) conditions looked nearly the same as the unheated fragments, with no nitrogen loss and little or no racemization of the amino acids.
"In contrast, the sample heated in indigenous water or water vapor, although it showed amounts of nitrogen similar to modern bone, showed the highest degree of amino acid racemization for any of the experimental simulation systems. This is the closed system model in which the racemized amino acids and peptides from the protein breakdown are retained in the bone material. With the liquid water present there are further dramatic effects due to leaching. When the ratio of water to bone is 10 to 1, around 85% of the protein is leached out of the bone, whereas in the experiment in which the water was changed frequently, the amount of protein leaching out was 95%. As more protein material is leached out, the proportion of D- and L-amino acids (percent racemization) in the bone fragment diminishes because more of the D-amino acids are leached out into the water." (1980:213).
"Since most bones from natural environments show diminishing amounts of protein material, it seems reasonable to conclude that some leaching has occurred. The absence of significant amounts of free amino acids from fossil bone is probably due to the fact that they have been leached out. In the water vapor experiment there was a continuous increase with time of the level of free amino acids from the protein breakdown. No significant levels were found in any of the continuously leached samples. The rate-determining step appears to be in the protein breakdown rather than the leaching of the breakdown products. This would suggest that even occasional or periodic leaching conditions would adequately remove the breakdown products formed by the reaction with water vapor during the ‘dry’ period. It may be possible to check this on bones in the field toward the end of an extended period of drought and after the next period of rainfall." (1980:217).
"Quantitative observations during the simulation experiments showed that, as water reacted with the protein in the bone fragments, the fragments became progressively chalkier and easier to break apart. Samples that had been leached extensively were generally easy to crush and cut. Fossil bone samples of pre-Pleistocene age frequently show much greater strength and hardness than younger fossils. In these cases the microstructure of bone has been strengthened, or, in some cases, completely replaced by mineral matter deposited from ground water. Structural details of original microstructure of the bone are often preserved, in contrast to the almost complete lack of preservation of any of the organic matrix components. Many of the chemical changes observed within minutes or hours in the laboratory treatment at relatively high temperatures (75°-150°C) should be observable within a few years at environmental temperatures (15°-20°C)." - Hare, P. E. (1980:218, 219).
Result
Even occasional or periodic leaching conditions would adequately remove the breakdown products by the reaction with water vapor during the ‘dry’ period. With liquid water present: When the ratio of water to bone is 10 to 1, around 85% of the protein are leached out of the bone. When the water is often changed, 95% of the protein is leached out.
Carbon replaced in Leached Bone
Richard Gillespie, Dept. of Biogeography and Geomorphology, Australian National University, at Canberra, says about "Fundamentals of Bone Degradation Chemistry: Collagen is not ‘the way’," in the famous scientific journal Radiocarbon:
"Collagen is very easily hydrolyzed under acid, neutral or basic conditions, leading to many free polar end groups; the gelatinization procedure used by some laboratories is a partial acid hydrolysis. It is the polar residues that cross-link the collagen polymer, and they can also combine (when freed by hydrolysis) with other amino acids, sugars, etc. from the environment, yielding a contaminated protein not amendable to purification by current methods. Although it was earlier believed that amino acids do not reversible exchange their carbon, evidence now supports exchange by reversible decarboxylation (Barret, 1985).
"It is also clear from published work that fossil collagen does not behave like modern collagen, probably due to degradation and diagenetic changes. ... Perhaps the days of collagen dating are numbered, at least for badly degraded bone where the newer biochemical techniques can be applied to the non-collagenous bone and blood proteins." - Gillespie, R. (1989: 242, 245).
Alaskan Mammoth Hair
How well is the hair of the Alaskan woolly mammoth preserved? What have scientists found out about this?
J. M. Gillespie reports in the journal Science: "Hair from a woolly mammoth (Mammoth primigenius), age about 32,000 years, retains the ordered structure characteristic of a-keratins. But the proteins of this hair differ in composition from and are smaller than similar proteins isolated from other keratins, for example, elephant hair. It is suggested that these changes have been caused by limited proteolysis.
"An opportunity to make such an examination was provided by the gift of mammoth hair from Professor Troy L. Péwé. This hair, obtained in 1951 from the remains of a mammoth (Mammuthus primigenius) uncovered at Dome Creek, Alaska, was dated by the radiocarbon method at 32,700 +/- 980 years B.P. ... For comparative purposes the hair of the closely related Indian elephant, Elephas maximus, has been used." (1970:1100).
"... the amino acid analyses of mammoth hair and its constituent proteins showed they differed from those of the elephant hair and its proteins in a way suggestive of a loss of some amino acid residues from mammoth hair. The most likely cause of the changes in size and composition seems to be limited enzymatic proteolysis. It is therefore suggested that proteolysis has split the protein chains at a number of points, resulting in the formation of a set of peptides of varying sizes. Small peptides may be leached from the fiber, whereas larger peptides, including cross-linked cystine peptides, may be unable to penetrate cell membranes or may be held firmly by molecular interactions. In this way a major change in composition could take place with only minimum changes in the physical structure of the fiber and its cystine content.
"A possible degrative agent is not hard to find, for, as Farrand has pointed out, most mammoths have been decomposed more or less extensively before being frozen, and it appears that this Dome Creek mammoth had been very extensively damaged. The putrid odor of many mammoth carcasses and the surrounding burial ground is sufficient proof of the existence of proteolytic enzymes in the environment of the hair. It would be considerable interest to see whether hair from a more recent mammoth or from one of the better preserved Siberian specimens shows less damage." - Gillespie, J. M. (1970:1101).