The earliest human footprints (Laetoli) occur in lake sediments that have been misinterpreted as datable volcanic ash

Allan Krill

The earliest human footprints (Laetoli) occur in lake sediments that have been misinterpreted as datable volcanic ash  
Allan Krill, Department of Geoscience, NTNU, Trondheim, krill@...  

An alternative paradigm of human evolution is the “aquatic-ape hypothesis,” in which our ancestors evolved naked skin, long head-hair, large brain, bipedal gait, subcutaneous fat (blubber), descended larynx, hooded nose, and all other human features, during a period of semiaquatic habitat. This unorthodox theory has been ridiculed in paleoanthropology for 60 years, just as the “continental-drift hypothesis” was ridiculed in geology in its time.   

The current paradigm is that human ancestors evolved on the eastern African savanna and were bipedal as early as 3.5 Ma ago. I contend that this history is based on errors — falsifications like Piltdown Man (e.g. Lucy, Turkana Boy, Little-Foot) — and geological misinterpretations (e.g. Laetoli). Humans may instead have evolved from chimpanzees that became isolated on Galapagos-like volcanic islands: proto-Bioko in western Africa, where fossils could not be preserved. No mammal fossils are known in any of the areas where chimpanzees speciated.   

The human footprint track at Laetoli is said to be 3.5 Ma old. That age is probably wishful thinking, and the layer less than 200 000 years old. Calcareous sediments have been interpreted to be volcanic ash, in which K-feldspar and biotite dates give meaningful ages.   

18 thin calcareous layers with mud cracks, raindrop marks, and footprint trails from hundreds of savanna animals (and even an insect), are interpreted to be fresh ashfall from 18 volcanic eruptions. The geology professor behind this interpretation thought that enough rain fell after each ashfall to dampen the ash so that it could preserve prints. There was not enough rain to wash the ash away from the flat, horizontal and grassless surface where the animals walked. I claim that this is an unreasonable geological interpretation.   

The layers are calcaerous, so it was thought that the ash was carbonatite from the Sadiman volcano. But ash of carbonatite is unknown in geology, and no carbonatite is found at Sadiman, or on the Laetoli-Serengeti Plain.   

Thin-section photos and chemical analyses of these so-called ash layers have never been published. Mineral grains giving K-Ar dates of 3.5 Ma have been claimed to be the age of the layers and the footprints. Grains giving inappropriate dates were discarded.   

To protect the footprints from vandalism, the layer was covered over by soil and blocks of rock, before the exciting results were published. This cover-up kept visiting geologists from suggesting that these were lake sediments that cannot be dated using detrital minerals. A lake-sediment hypothesis has never been mentioned.  

I am hoping to publish a paper exposing these errors. You can read the manuscript, with pdf references, here:  See also