Geology Legends and Misconceptions
#1) Groundwater exists as underground rivers and subterranean lakes or basins:
More Accurately... While it is possible that some caves and underground caverns contain pools of water and / or flowing streams, these are rare examples of how water exists underground. For the most part, groundwater flows slowly through the small connected pore spaces and / or fractures within solid rock layers such as sandstone or fractured limestone, or through the pores of unconsolidated sands and gravels, much in the same way water can pass through pore spaces within a sponge. Precipitation, snowmelt, and seepage from surface lakes and rivers soaks into the ground until the water hits a layer of rock or sediment that has no openings (or the openings are too tiny to let water easily pass through). The water then accumulates above this impermeable or less permeable layer until all pores and openings are saturated with water. The groundwater will then start flowing from areas of high elevation to low elevation, or in the case of an aquifer trapped between two impermeable confining layers, the water will flow from areas of high pressure to low pressure.
#2) The most accurate method for calculating the age of the earth is by radiocarbon (carbon-14) dating:
More Accurately... The carbon-14 radiometric dating method is useful for dating some materials but is only accurate for dating material that is in the range of thousands of years old, not millions or billions. Due to its relatively short half-life (5730 +/- 40 yrs), anything older than approximately 50,000 years should theoretically not have any detectable carbon 14 left. Most geologists accept the age of the earth to be close to 4.6 billion years based on radiometric dating of meteorites and lunar rocks. For now, the oldest object dated from earth is a tiny zircon grain collected from a rock sample from the Jack Hills of Western Australia. The radiometric age of this crystal is approximately 4.4 billion years old. The most common and accurate technique used to calculate the age of such very old material, as this zircon, is from the analysis of uranium and lead not carbon-14.
#3) Simple single-celled organisms were present when Earth first formed.
More Accurately... As noted in number two, Earth formed some 4.6 billion years ago along with the formation of the rest of our solar system. The oldest fossil record of life on Earth is estimated to be approximately 3.5 billion years old. Rocks of Western Australia and slightly younger rocks in South Africa contain microscopic spheroidal and thread-like filaments along with sedimentary structures that may be stromatolites. Stromatolites are finely layered, mound-shaped accumulations of mud trapped by growing mats of cyanobacterial communities. Cyanobacteria are very primitive photosynthetic prokaryotes (bacteria) that today grow in marine environments, producing mats of cell filaments that can mound-up with marine mud to produce structures several meters high. These early fossils show that life originated sometime after the first one billion years of the Earth's existence.