Senior Member
French - France
The context is a letter in Nature, "Organic-walled microfossils in 3.2-billion-year-old shallow-marine siliciclastic deposits". The abstract contains the following sentence:

Ambiguities and controversies persist regarding the biogenicity and syngeneity of the record older than Late Archaean.

The "record" here is made of would-be fossils. I understand that biogenicity refers to the fact that these fossils are (or not) remnants of living organisms, rather than morphologies resulting from non-biological physical processes. But what does syngeneity mean ?
  • Well, the OED doesn't have syngeneity, but it does have syngen:
    A group of organisms, esp. protozoans, capable of breeding together.
    and syngeneic:
    Immunologically compatible; (of a group of organisms) so closely related that their tissues do not act as antigens when transplanted to one another; = ISOGENEIC a
    Might these be relevant?
    I found this in a Google Books search. Sorry, I can't link because I'm a newbie...It is an old volume of the Journal of Geology.

    "Primary ore deposits are…classified as syngenetic (formed simultaneously with the country rock) and epigenetic (formed later than the country rock). Syngenetic deposits are divided into magmatic segregations and sedimentary ores."

    Thus, formed at the same time as the surrounding rock? Here is the definition of syngenetic ore: "An ore deposit formed simultaneously with the host rock and by similar processes, e.g. bedded ironstone, magmatic segregation deposits."

    I would guess that syngeneic and syngenetic are variations of the same word. :)
    The Greek derivation break down; syn=co, gen=birth (verb) seems to confirm Loob's finding in quote No 1.

    Edit: Did not see Doofy response when posting.
    It seems syngen and syngeneic belong to biology, while the adjective syngenetic and noun syngeneity are commonly used in geology. The meaning is clear now. Thanks a lot.