What is relative dating of rocks and fossils best dating place in guwahati
In 2014, Mary Schweitzer and her colleagues reported the presence of iron particles (goethite-a Fe O(OH)) associated with soft tissues recovered from dinosaur fossils.
Based on various experiments that studied the interaction of iron in haemoglobin with blood vessel tissue they proposed that solution hypoxia coupled with iron chelation enhances the stability and preservation of soft tissue and provides the basis for an explanation for the unforeseen preservation of fossil soft tissues.
In this case the fossil consists of original material, albeit in a geochemically altered state.
This chemical change is an expression of diagenesis.
Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in amber, hair, petrified wood, oil, coal, and DNA remnants.A shell is said to be recrystallized when the original skeletal compounds are still present but in a different crystal form, as from aragonite to calcite.Compression fossils, such as those of fossil ferns, are the result of chemical reduction of the complex organic molecules composing the organism's tissues.Often what remains is a carbonaceous film known as a phytoleim, in which case the fossil is known as a compression.Often, however, the phytoleim is lost and all that remains is an impression of the organism in the rock—an impression fossil.