CH210: Age of the Earth

Claim CH210:

Source:

Response:

1. Radiometric dating shows the earth to be 4.5 billion years old (see CD010 regarding the reliability of radiometric dating).
   
   
2. If the earth is old, then radioactive isotopes with short half-lives should have all decayed already. That is what we find. Isotopes with half-lives longer than eighty million years are found on earth; isotopes with shorter half-lives are not, the only exceptions being those that are generated by current natural processes (Dalrymple 1991, 376-378).
   
   
3. Loess deposits (deposits of wind-blown silt) in China are 300 m thick. They give a continuous climate record for 7.2 million years. The record is consistent with magnetostratigraphy and habitat type inferred from fossils (Ding et al. n.d.; Russeau and Wu 1997; Sun et al. 1997).
   
   
4. Varves are annual sediment layers that occur in large lakes. They are straightforward to measure, cover millions of years, and correlate well with other dating mechanisms.
   
   
   • In seasonal areas, sedimentation rates vary across the year, so sediments often show annual layers (varves) distinguished by texture and/or composition. We can be confident that the layers are seasonal because we see the same sorts of layers occurring today. Even if they were not seasonal, the fineness of the sediments is often such that each layer would require several days, at least, to form. Some formations have millions of layers, such as the varve record from Lake Baikal with five million annual layers (Williams et al. 1997), and the 20,000,000 layers in the Green River formation. They must have taken hundreds of thousands of years to form at the very least.
     
     
   • Dates obtained by counting annual layers of varves match dates obtained from radiometric dating. One varve formation, covering 45,000 years, was used to calibrate carbon-14 dating using terrestrially produced leaves, twigs, and insect parts that also appeared in the sediments. The varves were easy to count because they included an annual diatom bloom (Kitagawa and van der Plicht 1998).
     
     
   • Varves record climate changes, too, since climate affects the amount of sediments. Climate is affected by orbital cycles known to occur at about 400,000-, 600,000-, and million-year periods (the so-called Milankovitch cycles). Climate cycles of these durations occur in the varve records. For example, Lake Baikal contains annual layers from twelve million years ago to the present. These sediments contain periodic changes matching the orbital cycles (Kashiwaya et al. 2001).
   
   
5. The abundance and distribution of helium change predictably as the sun ages, converting hydrogen to helium in its core. These parameters also affect how sound waves move through the sun. Thus one may estimate the sun's age from seismic solar data. Such an analysis puts the age of the sun at 4.66 billion years, plus or minus about 4 percent (Dziembowski et al. 1999).

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