Proof that evolution is the only answer

a reply to: cooperton

Since you seem to be having issues with Radiometric dating. Here is some reading for you

Dalrymple, G. B., (2004) Ancient Earth, Ancient Skies: The Age o the Earth and Its Cosmic Surroundings. Stanford: Stanford University Press.

Marshak, S., (2008). Earth: Portrait of a Planet. Third Edition. New York: W. W. Norton & Company.

Hedman, M. (2007). The Age of Everything. Chicago: University of Chicago Press.

Isaak, M. (2004). CF210: Constancy of Radioactive Decay Rates. Talk.Origins. www.talkorigins.org... Accessed 2011-08-12.

Isaak, M. (2004). CD001: Geochronometry and closed systems. www.talkorigins.org... Accessed 2011-08-12.

Isaak, M. (2004). Geochronology and initial conditions. www.talkorigins.org... Accessed 2011-08-12.

That "paper" you linked, was not a paper. The APPT is the American Association of Physics Teachers

originally posted by: AshFan
"Creation science" is a contradiction in terms. A central tenet of modern science is methodological naturalism--it seeks to explain the universe purely in terms of observed or testable natural mechanisms. Thus, physics describes the atomic nucleus with specific concepts governing matter and energy, and it tests those descriptions experimentally. Physicists introduce new particles, such as quarks, to flesh out their theories only when data show that the previous descriptions cannot adequately explain observed phenomena. The new particles do not have arbitrary properties, moreover--their definitions are tightly constrained, because the new particles must fit within the existing framework of physics.

Read and learn:

www.scientificamerican.com...

evolution is real so is creation. I work for the universe.

The earth cannot be measured by time.

originally posted by: cooperton

originally posted by: peter vlar
a reply to: AshFan

These tests are the oldest and most refined radiometric dating techniques being used in geology and archaeology because of the predictable rates of decay.

How is the starting date determine? We know decay rate, and the currently measured ratio, but how do we know the starting Uranium-Lead Ratio ? Or is this based on assumptions?

Actually, that's a good question - but I wish you would STOP using "assumptions". Assumption in laymans' terms implies that there is no hard data to support the result of the experiment. That is INCORRECT. I know the crackpot websites like ICR use that excuse all the time - everything is an assumption. Ridiculous.

Anyway, on to the the crux of uranium/lead dating methods (note the "s" - there are several methods).

Lead leaching from samples was indeed a problem with U/Pb dating methods. Extensive research and testing resulted in much more accurate method(s) of dating geological samples - see page 356, "4.10.5 Precision and Accuracy of U–Th–Pb
Geochronology" in the citation link below.

Coop, this paper is an excellent example of how detailed testing and analysis can overcome inherent problems in certain methods. Sophisticated instrumentation and statistical models continue to improve how well we understand these processes.

I think you're really interested in this stuff so please take the time to go over the plots and diagrams - there's a lot of excellent information in this paper. Many of your questions would be answered in the Methods section on page 351:
"4.10.4 Measurement Techniques". Methods is where the rubber meets the road in all science - how it was done.

Peter gave an excellent explanation about the occurrence of the element uranium in nature. Uranium is found mostly as oxides - uranium dioxide, etc. The basis for the U/Pb dating method was actually the concordant decay rates of uranium and lead - if you read the paper, you'll come across an explanation of concordant/discordant plots.

U–Th–Pb Geochronology
Blair Schoene, Princeton University, Princeton, NJ, USA

www.princeton.edu...

4.10.1 Introduction
The year 2011 marked the one hundredth anniversary of what
may be the first real geochronology paper, published by Arthur
Holmes, entitled “The Association of Lead with Uranium in
Rock-Minerals and Its Application to the Measurement of
Geological Time” (Holmes, 1911). Holmes’ early work was
surprisingly accurate, even though it was carried out prior to
the discovery of isotopes (Soddy, 1913) and restricted to
whole-rock geochemical analyses. This and complementary
efforts examining U decay and utilizing U–Pb chemical geochronology
laid the foundation for what was to become one of the most important isotopic dating
methods, capable of measuring the timescales of events from
the early solar system !4.57 Ga into the Pleistocene.

We now know that the element lead has four naturally
occurring stable isotopes, 204Pb, 206Pb, 207Pb, and 208Pb, of
which the latter three have a radiogenic component produced
through the independent decay of 238U, 235U, and 232Th,
respectively.

The abundance of high-U minerals in most rock
types, as well as the resistance of many of these minerals to
chemical and physical weathering, contributes to the popularity
and prolificacy of the U–Pb system. Though zircon is by far
the most commonly utilized mineral for U–Pb dating
(Hanchar and Hoskin, 2003), monazite, apatite, xenotime,
titanite, rutile, baddeleyite, allanite, and perovskite are also
commonly dated and provide a spectrum of geochronologic
and thermochronologic applications in i Combined with whole-rock partial
dissolution techniques of increasing sophistication (Amelin
et al., 2009; Connelly and Bizzarro, 2009; Connelly et al.,
2008; Wadhwa et al., 2009), the U–Pb system has provided
crucial time constraints for the formation of the solar system,
the calibration of the geologic timescale, the rates of tectonothermal
processes in the lithosphere, and the reconstruction
of paleogeography and supercontinent cycles.

The amount of material in a given analysis has continually
decreased and the precision of analyses has increased since mass
spectrometers were first applied to U–Pb geochronology in the
1960s. The last decade has seen an explosion of U–Pb data in the
literature (Figure 1), in part because of the ease of dating high-U
minerals in situ through the application of laser ablation
methods to geochronology. However, more time-intensive
high-precision U–Pb geochronology has remained the standard
to which all other geochronologic methods are compared. An
increasing number of other radioisotope decay constants are
calibrated directly against the U decay constants through geochronologic
methods (Nebel et al., 2011; Renne et al., 2010; Scherer
et al., 2001; Selby et al., 2007), and the timescales of early solar
system differentiation based on the decay of extinct radionuclides
are connected to the absolute U–Pb timescale (Kita et al., 2005;
Wadhwa et al., 2009). This is in part because the U decay
constants are the most precisely determined among all geochronologic
decay schemes (Begemann et al., 2001; Jaffey et al.,
1971), but also because their accuracy is cross-calibrated with
one another through high-precision geochronology of closedsystem
minerals (Mattinson, 2000, 2010; Schoene et al., 2006).
The benefit of the dual U decay thus goes further to provide an
internal check for closed-system behavior over long timescales,
cross-checking the accuracy of many age determinations and also
yielding information on multiple geologic events from single
datasets (Tera and Wasserburg, 1972a; Wetherill, 1956).

This chapter focuses on modern U–Th–Pb geochronology
of relatively high-U–Th minerals in high-temperature systems.
It does not adequately cover exciting related fields of geochronology,
such as U-series dating, for which the reader is referred
elsewhere (e.g., Bourdon et al., 2003; Chapters 4.5 and 4.15,
and references therein).

a reply to: Phantom423

Thanks for that. From what I've read, the term for initial lead concentration is called "common lead". But they avoid the question of how to the isotopic ratio that would have been present millions, and billions of years ago. I understand mass spectrometry is very accurate, and that is not what I am disputing, because I am well aware we can accurately measure isotopic ratios. One of the nicer things about carbon-dating is that we have a reasonable estimate of initial C-14 in the system due to presently observed C-14 atmospheric levels.

But for Uranium-Lead dating I see no reliable way to estimate, let alone know, the initial isotopic ratios. and without such a certainty, I don't see how they can be certain about any dates that result from this method.