Life Influences Dating Method

The rate of calcium carbonate precipitation can double if microbes are present, says an article in PhysOrg.  Scientists studying hot spring deposits in Yellowstone made this “surprising discovery about the geological record of life and the environment.”  The article adds, “Their discovery could affect how certain sequences of sedimentary rock are dated, and how scientists might search for evidence of life on other planets.”
    The travertine terraces at Mammoth Hot Springs in Yellowstone can grow millimeters per day.  The precipitation can actually “more than double” when microbes are present, the article said.  Calcium carbonate is the most abundant mineral in the rock record.
    The scientists believe that inferences about the presence of life can be drawn from studying the rate of deposition.  “Separating biologically precipitated calcium carbonate from non-biologically precipitated calcium carbonate is difficult,” however.  Inferences about life would also require independent knowledge about the rate of deposition.  They believe they can tease this information out from the chemistry, based on “the environmental and ecological context of the rock being studied.”

The important observation here is that previous trusted assumptions about most common sedimentary rock were off by more than a factor of two.  What other assumptions are still unquestioned that will be overturned in the future?  Other questions: What will this do to cave formation dating methods?  Will they change the textbooks within the next decade?  How can they rightfully infer the presence of life from a precipitation rate on a planet where no life has been found, when other unknown factors could influence the rate?  How come geologists never apologize for the misinformation they spread?