In
this message I was asked to post some links on radioisotope dating. Here's what I've culled from my collection:
General Introductions
Radiometric Dating: A Christian PerspectiveA fairly technical but readable explanation of isochron techniques at
Isochron Dating.
Pb-Pb isochron dating and the age of the Earth is discussed at
The Age of the Earth.
Collections of Links
Dating Methods in Science has very brief descriptions of a multitude of techniques and links to more explanations.
Tim Thompson maintains
A Radiometric Dating Resource List, more brief discussions and links; the first part is responses to creationist claims and the second part covers various dating subjects.
Changes in Decay Rates
Modifications of Nuclear Beta Decay Rates: Post of the Month: March 2001
Consistency of different methods
Radiometric DatingConsistent Radiometric datesRadio-isotopic dating, a PDF document including several tables and figures from Dalrymple's "The Age of the Earth" and some discussion of dating methods.
Precise dating of the destruction of Pompei press release on dating the destruction of Pompeii using Ar-Ar dating (note that the lava that was dated contained "excess argon").
40Ar/39Ar Dating into the Historical Realm: Calibration Against Pliny the Younger, the Science abstract (free registration required for full article).
C-14 (not one of my major interests)
How does the radiocarbon dating method work?Radiocarbon WebLake VarvesThe Cologne Radiocarbon Calibration & Paleoclimate Research Package
Earth's oldest minerals: 4.3 to 4.4 billion
Earlier Water on Earth? Oldest Rock Suggests Hospitable Young PlanetEvidence from detrital zircons for the existence of continental crust and oceans on the Earth 4.4 Gyr agoOxygen isotope ratios and rare earth elements in 3.3 to 4.4 Ga zircons: Ion microprobe evidence for high d18O continental crust and oceans in the Early Archean.
Advanced material
Sample PreparationU-Pb isotopic datingHome page of
a course in isotope geochemistry includes a compete set of detailed lecture notes in PDF form.
Radiogenic Isotope Geology, a draft (no figures) of the next edition of one of the classic and standard textbooks and reference works. This may go away at any time.
U-Th-He dating
Dating sedimentary rocks
The latest thing (still being developed) is dating the sedimentary rock in which the fossil is found. This is made possible by using a Sensitive High-Resolution Ion MicroProbe (SHRIMP), which can measure incredibly small samples. The analysis is performed by dating a mineral called xenotime, which forms between the grains when the sedimntary rock lithifies.
U-Pb SHRIMP Dating of Diagenetic XenotimeSHRIMPXenotime / zircon geochronology in the Archaean Witwatersrand Basin (a PDF document, highly technical).
What methods are used today?
Although I don't think I should post it all, I believe it's fair use to quote from a personal communication from
Dr. Ken Ludwig on 3 March, 2003:
"As an example (see attached figure), for a review of an article a few months ago I did a quick literature search of articles presenting new geochronology (excluding rocks of Pleistocene age. for which methods such as radiocarbon, uranium series, optical luminescence.... are important) in a variety of different journals (Geology, Geol. Soc. Amer. Bull., Canadian Jour. Earth Sci., Contrib. Mineralogy & Petrology) for the past 5 years. Of the 164 articles I selected at random, more than 80% were done by either U-Pb (54%) or Ar-Ar/ K-Ar (30%). with less than 5% each were done by Rb-Sr or Sm -Nd."
The accompanying figure shows (approximately, since I'm reading the numbers off a graph):
U-Pb1 | 54% |
Ar2 | 30% |
Fission Track | 7% |
Rb-r3 | 4% |
Sm-Nd3 | 3% |
U-Th-He | 1% |
Re-Os3 | 1% |
Notes:
1. Mostly concordia-discordia.
2. "Ar" includes both K-Ar (a "simple" method") and Ar-Ar (an isochron method).
3. An isochron method.
This material may have been published somewhere by now, but if so I don't know where.
This message has been edited by JonF, 03-09-2005 09:39 AM