Claim CD011.1:
Carbon dating is based on the atmospheric C-14/C-12 ratio, but that ratio
varies. Thus the carbon dating method is not valid.
Source:
Morris, Henry M. 1985. Scientific Creationism. Green Forest, AR: Master
Books, pp. 162-166.
Response:
- The variability of the C-14/C-12 ratio, and the need for calibration, has
been recognized since 1969 (Dickin 1995, 364-366). Calibration is
possible by analyzing the C-14 content of items dated by independent
methods. Dendrochronology (age dating by counting tree rings) has been
used to calibrate C-14/C-12 ratios back more than 11,000 years before
the present (Becker and Kromer 1993; Becker et al. 1991). C-14 dating
has been calibrated back more than 30,000 years by using
uranium-thorium dating of corals (Bard et al. 1990; Edwards
et al. 1993), to 45,000 yeas ago by using U-Th dates of glacial
lake varve sediments (Kitagawa and van der Plicht 1998), and to 50,000
years ago using ocean cores from the Cariaco Basin which have been
calibrated to the annual layers of the Greenland Ice Sheet (Hughen et
al. 2004).
Links:
Matson, Dave E., 1994. How good are those young-earth arguments?
http://www.talkorigins.org/faqs/hovind/howgood-c14.html#R1
References:
- Bard, E., B. Hamelin, R. G. Fairbanks and A. Zindler. 1990.
Calibration of the 14C timescale over the past 30,000 years
using mass spectrometric U-Th ages from Barbados corals.
Nature 345: 405-410.
- Becker, B. and B. Kromer. 1993. The continental tree-ring record --
absolute chronology, 14C calibration and climate change at
11 ka. Palaeogeography, Palaeoclimatology, Palaeoecology 103:
67-71.
- Becker, B., B. Kromer and P. Trimborn. 1991. A stable-isotope tree-ring
timescale of the Late Glacial/Holocene boundary. Nature 353:
647-649.
- Dickin, A. P. 1995. Radiogenic Isotope Geology, Cambridge
University Press.
- Edwards, R. L. et al. 1993. A large drop in atmospheric
14C/12C and reduced melting in the Younger Dryas,
documented with 230Th ages of corals. Science 260:
962-968.
- Hughen, K. et al. 2004. 14C activity and global carbon
cycle changes over the past 50,000 years. Science 303: 202-207.
See also Bard, E., F. Rostek and G. Ménot-Combes. 2004. A
better radiocarbon clock. Science 303: 178-179.
- Kitagawa, H. and J. van der Plicht. 1998. Atmospheric radiocarbon
calibration to 45,000 yr B.P.: Late glacial fluctuations and cosmogenic
isotope production. Science 279: 1187-1190. See also Kitagawa,
H. and J. van der Plicht, 2000. PE-04. A 45.000 year varve chronology
from Japan. http://www.cio.phys.rug.nl/HTML-docs/Verslag/97/PE-04.htm
Further Reading:
Dalrymple, G. Brent, 1991. The Age of the Earth. Stanford University
Press.
Lowe, J. John, ed., 1991. Radiocarbon dating: Recent applications and
future potential. Quaternary Proceedings Number 1, 1991, Published
for the Quaternary Research Association, Wiley.
created 2001-2-18, modified 2006-1-3