Lazarus bacteria—bacteria revived from salt inclusions supposedly 250 million years old, suggest the salt is not millions of years old. See also Salty saga.
The decay in the human genome due to multiple slightly deleterious mutations each generation is consistent with an origin several thousand years ago. Sanford, J., Genetic entropy and the mystery of the genome, Ivan Press, 2005; see review of the book and the interview with the author in Creation30(4):45–47,September 2008. This has been confirmed by realistic modelling of population genetics, which shows that genomes are young, in the order of thousands of years. See Sanford, J., Baumgardner, J., Brewer, W., Gibson, P. and Remine, W., Mendel’s Accountant: A biologically realistic forward-time population genetics program, SCPE 8(2):147–165, 2007.
The data for ‘mitochondrial Eve’ are consistent with a common origin of all humans several thousand years ago.
Very limited variation in the DNA sequence on the human Y-chromosome around the world is consistent with a recent origin of mankind, thousands not millions of years.
Many fossil bones ‘dated’ at many millions of years old are hardly mineralized, if at all. This contradicts the widely believed old age of the earth. See, for example, Dinosaur bones just how old are they really? Tubes of marine worms, ‘dated’ at 550 million years old, that are soft and flexible and apparently composed of the original organic compounds hold the record (original paper).
Dinosaur blood cells, blood vessels, proteins (hemoglobin, osteocalcin, collagen, histones) and DNA are not consistent with their supposed more than 65-million-year age, but make more sense if the remains are thousands of years old (at most).
Lack of 50:50 racemization of amino acids in fossils ‘dated’ at millions of years old, whereas complete racemization would occur in thousands of years.
Living fossils—jellyfish, graptolites, coelacanth, stromatolites, Wollemi pine and hundreds more. That many hundreds of species could remain so unchanged, for even up to billions of years in the case of stromatolites, speaks against the millions and billions of years being real.
Discontinuous fossil sequences. E.g. Coelacanth, Wollemi pine and various ‘index’ fossils, which are present in supposedly ancient strata, missing in strata representing many millions of years since, but still living today. Such discontinuities speak against the interpretation of the rock formations as vast geological ages—how could Coelacanths have avoided being fossilized for 65 million years, for example? See The ‘Lazarus effect’: rodent ‘resurrection’!
The ages of the world’s oldest living organisms, trees, are consistent with an age of the earth of thousands of years.