Of course there are other methods behind C14 -- but the point is that C14 should be undetectable after about 50,000 years. So these fossils wuth detectable C14 have a little problem...how can they be millions of years old and still have C14 in them? Don't worry, though, the answer is only as far as one's imagination.
I like that first link, saw. Let's have a look.
Paleontologists use many ways of dating individual fossils in geologic time.
Ah, good. So one method can be used to check another, right?
The oldest method is stratigraphy, studying how deeply a fossil is buried. Dinosaur fossils are usually found in sedimentary rock. Sedimentary rock layers (strata) are formed episodically as earth is deposited horizontally over time. Newer layers are formed on top of older layers, pressurizing them into rocks.
This is called a hypothesis. Another hypothesis is that the great flood caused the layering, in which case the older dates would be grossly incorrect.
Paleontologists can estimate the amount of time that has passed since the stratum containing the fossil was formed.
Yes, they can guess. And since the stratum varies dramatically depending upon the location (layers can be thin, thick, or missing entirely), this guess could be grossly inaccurate, since nobody was there to see WHY the layer is thinner, thicker, or missing. Erosion? Sedimentation? Deposition by flood?
Generally, deeper rocks and fossils are older than those found above them.
Yes, generally. And when the younger fossils are buried below the older ones, geologists simply explain it away by assuming there was an overthrust. So here you have dating by assumption, and special pleading for the exceptions.
Observations of the fluctuations of the Earth's magnetic field, which leaves different magnetic fields in rocks from different geological eras.
How did you date the fluctuations in the magnetic field? Under the assumption of an old earth, maybe? And then you are applying those dates to the rocks?
Dating a fossil in terms of approximately how many years old it is can be possible using radioisotope-dating of igneous rocks found near the fossil. Unstable radioactive isotopes of elements, such as Uranium-235, decay at constant, known rates over time (its half-life, which is over 700 million years). An accurate estimate of the rock's age can be determined by examining the ratios of the remaining radioactive element and its daughters. For example, when lava cools, it has no lead content but it does contain some radioactive Uranium (U-235). Over time, the unstable radioactive Uranium decays into its daughter, Lead-207, at a constant, known rate (its half-life). By comparing the relative proportion of Uranium-235 and Lead-207, the age of the igneous rock can be determined. Potassium-40 (which decays to argon-40) is also used to date fossils.
This is dealt with extensively elsewhere (excessive argon problems, dating of rocks only 10 years old as if they were millions of years old, etc.)
The half-life of carbon-14 is 5,568 years. That means that half of the C-14 decays (into nitrogen-14) in 5,568 years. Half of the remaining C-14 decays in the next 5,568 years, etc. This is too short a half-life to date dinosaurs;
It's also too short to date coal. So why is there measurable C14 in virtually all coal?
Radioisotope dating cannot be used directly on fossils since they don't contain the unstable radioactive isotopes used in the dating process. To determine a fossil's age, igneous layers (volcanic rock) beneath the fossil (predating the fossil) and above it (representing a time after the dinosaur's existence) are dated, resulting in a time-range for the dinosaur's life. Thus, dinosaurs are dated with respect to volcanic eruptions.
That's what I said. They don't date the fossils, they date the rocks.
Looking for index fossils - Certain common fossils are important in determining ancient biological history.
The rocks date the fossils and the fossils date the rocks. Circular reasoning.