"Biomarkers, molecular fossils, are organic compounds in Holocene to
Precambrian sedimentary deposits that can be related to specific chemical
compounds produced in the biosphere. We demonstrate here that
24-norcholestane biomarkers, i.e, C26 steranes (saturated hydrocarbons
having a steroid skeleton), can be useful to constrain the age and
paleolatitude of geologic samples. The biological precursors of
24-norchloestanes remain unclear, but samples from more than 100 basins
provide evidence that 24-norcholestanes show an initial increase above
background in Jurassic oils, but they increase dramatically in Cretaceous
oils, coincident with diatom evolution. The highest ratios are found in
oils and rock extracts from Oligocene or younger marine siliceous source
rocks in which the sources were deposited at paleolatitudes greater than
30[deg] N" ~ A. G. Holba et al, "24-norcholestanes as Age-sensitive
Molecular Fossils," Geology 26(1998):783-786, p. 783
Now, what are the possibilities:
1. Diatoms lived in the oceans prior to the Cretaceous part of the flood,
but they didn't die. Given the supposed violence of the flood, this seems
unlikely as the waters should have been thoroughly mixed up and the
microscopic diatoms should have been found with microscopic conodonts and
other small evidences of life in the Paleozoic
2. Diatoms fled with the dinosaurs and were washed into the sea later.
This is Morris' hydrodynamic sorting and ecological zonation hypothesis.
Morris suggests that dinos and men were able to flee to the hills and avoid
burial in the early part of the flood and escape early burial. It seems
difficult to envision diatoms fleeing to the hills.
3. Diatoms only lived in freshwater before the flood and they didn't enter
the flood until the waters washed them into the sea. The difficulty with
this is that fresh water deposits, without any diatoms are found in the
Paleozoic.
4. Diatoms actually evolved in the Cretaceous rocks as evolution and
paleontology says.
The same line of reasoning goes for another chemical found in petroleum,
oleananes, which are manufactured only by angiosperms. Angiosperms first
appear early in the Cretaceous but don't become numerous until the
Maastrichtian at the very end of the Cretaceous. And guess what?
Oleananes also follow this pattern.
"The results of the oleanane analyses are broadly comparable with
those found for fossil angiosperm occurrences. The relative concentrations
of oleanane to hopane, excluding the unusual Middle Jurassic and Neocomian
occurrences, begin low, near the detectable limit of 3% during the Early
Cretaceous and steadily incrase to a plateau during the latest Cretaceous.
Then, during the Tertiary there is a major increase." J. Michael Moldowan
et al, "the Molecular Fossil Record of Oleanane and Its Relation to
Angiosperms," Science 265(1994):768-771, p. 769
The question for the global flood advocates is: Why do the chemicals found
in petroleum not show the presence of preflood diatoms and angiosperms?
glenn
Adam, Apes and Anthropology
Foundation, Fall and Flood
& lots of creation/evolution information
http://www.isource.net/~grmorton/dmd.htm