A discussion of the strengths and weaknesses of conventional radiometric dating (which yields billions of years for the age of the earth) is given at Dating the Earth.A few of the non-conventional dating 'clocks' (which invariably point to a young earth) are also discussed.
"Creationism appears to be virtually absent from the mainstream denomination churches such as Anglican, Catholic, Baptist Union, Methodist, United Reformed Church and the Church of Scotland" [British Centre for Science Education] Despite the scepticism of mainstream churches, Creation Science aims to provide scientific support for YE Creationism.
So standard radiometric dating must be corrected for this early accelerated decay rate, reducing millions of years to thousands!
For example, the RATE project looked at nuclear-decay-generated helium (He) in microscopic zircons (Zr Si O4 crystals) and concluded: "Combining rates and retentions gives a He diffusion age of 6000 2000 years.
The clash between OE dating (millions or billions of years) and YE dating (thousands of years) centres on the decay constant K.
OE dating rests on the evolutionary concept of uniformitarianism and an assumed constant decay rate for all time. The Decreasing Speed of Light: There is strong scientific support for an exponential (rapid) reduction in the speed of light, 'c', shortly after creation, see Atomic Constants, Light & Time and Is the Velocity of Light Constant in Time? In 1999, Albrecht and Magueijo proposed a reduction in 'c' over time as a solution to cosmological puzzles.