Cosmogenic nuclide dating of Australopithecus at Sterkfontein, South Africa
Darryl E Granger cs 2022
PNAS 119 (27) e2123516119
doi org/10.1073/pnas.2123516119

Australopithecus fossils from the richest hominin-bearing deposit at StF (Member-4) are
- considerably older than previously argued by some,
- contemporary with Au.afarensis in E.Africa.
Our dates demonstrate the limitations of the widely accepted concept that Au.africanus (well represented at StF) descended from Au.afarensis.

The contemporaneity of the 2 spp now suggests:
a more complex family-tree prevailed early in the human (not human but hominid! --mv) evolutionary process.
The dates
- highlight the limitations of faunal age estimates previously relied upon for the S.African sites,
- demonstrate the importance of detailed stratigraphic analysis in assessments of accurate dating of the karst cave sites in S.Africa, which are stratigraphically highly complex.

Abstract

StF is the most prolific single source of Australopithecus fossils,
the vast majority were recovered from Member-4, a cave breccia now exposed by erosion, weathering at the landscape surface.
A few other Australopithecus fossils (incl. StW-573) come from subterranean deposits (Partridge cs 2003 Sci.300:607, Clarke cs 2019 Hum.Evol.134,102634).
Here, we report
- a cosmogenic nuclide isochron burial date of 3.41 ± 0.11 Ma, within the lower middle part of Member-4,
- simple burial dates of 3.49 ± 0.19 Ma in the upper middle part of Member-4, and 3.61 ± 0.09 Ma in Jacovec Cavern.
Together with a previously published isochron burial date of 3.67 ± 0.16 Ma for StW-573 (Granger cs 2015 Nature 522:85), these results place nearly the entire Australopithecus assemblage at StF mid-Pliocene,
i.e. contemporaneous with Au.afarensis in E.Africa.
Our ages for the fossil-bearing breccia in Member-4 are considerably older than the previous ages of c 2.1-2.6 Ma, interpreted from flow-stones ass.x the same deposit.
We show:
- these previously dated flow-stones are stratigraphically intrusive within Member 4,
- they therefore under-estimate the true age of the fossils.

_____

:-)
Yes, Pliocene "gracile" afarensis & africanus (aquarboreal?) apparently evolved in parallel to early-Pleistocene "robust" boisei resp. robustus (still aquarboreal??).
IMO (Hum.Evol.papers), the E.African afarensis->boisei belonged to Gorilla, the S.Afr.africanus->robustus to Pan (for refs, google "aquarboreal").
If we call the S.Afr.fossil subgenus "Australopithecus" (africanus & robustus), the E.Afr.fossil subgenus could be called "Paranthropus" or even "Zinjanthropus" (afarensis & boisei).

littor...@gmail.com wrote:
> Cosmogenic nuclide dating of Australopithecus at Sterkfontein, South Africa
> Darryl E Granger cs 2022
> PNAS 119 (27) e2123516119
> doi org/10.1073/pnas.2123516119

The REAL text, not what you made up

https://www.pnas.org/doi/epdf/10.1073/pnas.2123516119

Significance
Australopithecus fossils from the richest hominin-bearing deposit (Member 4)
at Sterkfontein in South Africa are considerably older than previously argued
by some and are contemporary with Australopithecus afarensis in East Africa.
Our dates demonstrate the limitations of the widely accepted concept that
Australopithecus africanus, which is well represented at Sterkfontein,
descended from A. afarensis. The contemporaneity of the two species now
suggests that a more complex family tree prevailed early in the human
evolutionary process. The dates highlight the limitations of faunal age
estimates
previously relied upon for the South African sites. They further
demonstrate the
importance of detailed stratigraphic analysis in assessments of accurate
dating
of the karst cave sites in South Africa, which are stratigraphically
highly complex.

Abstract
Sterkfontein is the most prolific single source of Australopithecus
fossils, the vast
majority of which were recovered from Member 4, a cave breccia now exposed
by erosion and weathering at the landscape surface. A few other
Australopithecus
fossils, including the StW 573 skeleton, come from subterranean deposits
[T. C.
Partridge et al., Science 300, 607–612 (2003); R. J. Clarke, K. Kuman,
J. Hum. Evol. 134, 102634 (2019)]. Here, we report a cosmogenic nuclide
isochron
burial date of 3.41 ± 0.11 million years (My) within the lower middle part of
Member 4, and simple burial dates of 3.49 ± 0.19 My in the upper middle part
of Member 4 and 3.61 ± 0.09 My in Jacovec Cavern. Together with a previously
published isochron burial date of 3.67 ± 0.16 My for StW 573 [D. E.
Granger et al.,
Nature 522, 85–88 (2015)], these results place nearly the entire
Australopithecus assemblage at Sterkfontein in the mid-Pliocene,
contemporaneous with
Australopithecus afarensis in East Africa. Our ages for the fossil-bearing
breccia in
Member 4 are considerably older than the previous ages of ca. 2.1 to 2.6 My
interpreted from flowstones associated with the same deposit. We show that
these previously dated flowstones are stratigraphically intrusive within
Member 4
and that they therefore underestimate the true age of the fossils.

"Ecological reconstructions from the Member 4 fauna indicate a climate more
humid than today, with mosaic grassland, savanna, and gallery forest,
consistent with
both C3 and C4 diets determined from fossil teeth (49). The Member 5 fauna is
associated with a drying climate and far more grazers (49). "

"savanna"

Op woensdag 29 juni 2022 om 07:30:19 UTC+2 schreef Primum Sapienti:

> > Cosmogenic nuclide dating of Australopithecus at Sterkfontein, South Africa
> > Darryl E Granger cs 2022
> > PNAS 119 (27) e2123516119
> > doi org/10.1073/pnas.2123516119

> The REAL text, not what you made up
> ... "savanna" ...

:-DDD
My little boy, you're the most idiotic of the kudu runners...
Do you understand the word "flow-stones"??

But the importance of this paper is that africanus did not evolve from afarensis, as anthropocentric PAs (kudu runners) like to believe.
IOW, Pliocene "gracile" afarensis & africanus (aquarboreal) evolved in // to early-Pleistocene "robust" boisei resp. robustus.

On Wednesday, June 29, 2022 at 1:30:19 AM UTC-4, Primum Sapienti wrote:
> littor...@gmail.com wrote:
> > Cosmogenic nuclide dating of Australopithecus at Sterkfontein, South Africa
> > Darryl E Granger cs 2022
> > PNAS 119 (27) e2123516119
> > doi org/10.1073/pnas.2123516119
> The REAL text, not what you made up
>
> https://www.pnas.org/doi/epdf/10.1073/pnas.2123516119
>
> Significance
> Australopithecus fossils from the richest hominin-bearing deposit (Member 4)
> at Sterkfontein in South Africa are considerably older than previously argued
> by some and are contemporary with Australopithecus afarensis in East Africa.
> Our dates demonstrate the limitations of the widely accepted concept that
> Australopithecus africanus, which is well represented at Sterkfontein,
> descended from A. afarensis. The contemporaneity of the two species now
> suggests that a more complex family tree prevailed early in the human
> evolutionary process. The dates highlight the limitations of faunal age
> estimates
> previously relied upon for the South African sites. They further
> demonstrate the
> importance of detailed stratigraphic analysis in assessments of accurate
> dating
> of the karst cave sites in South Africa, which are stratigraphically
> highly complex.
>
> Abstract
> Sterkfontein is the most prolific single source of Australopithecus
> fossils, the vast
> majority of which were recovered from Member 4, a cave breccia now exposed
> by erosion and weathering at the landscape surface. A few other
> Australopithecus
> fossils, including the StW 573 skeleton, come from subterranean deposits
> [T. C.
> Partridge et al., Science 300, 607–612 (2003); R. J. Clarke, K. Kuman,
> J. Hum. Evol. 134, 102634 (2019)]. Here, we report a cosmogenic nuclide
> isochron
> burial date of 3.41 ± 0.11 million years (My) within the lower middle part of
> Member 4, and simple burial dates of 3.49 ± 0.19 My in the upper middle part
> of Member 4 and 3.61 ± 0.09 My in Jacovec Cavern. Together with a previously
> published isochron burial date of 3.67 ± 0.16 My for StW 573 [D. E.
> Granger et al.,
> Nature 522, 85–88 (2015)], these results place nearly the entire
> Australopithecus assemblage at Sterkfontein in the mid-Pliocene,
> contemporaneous with
> Australopithecus afarensis in East Africa. Our ages for the fossil-bearing
> breccia in
> Member 4 are considerably older than the previous ages of ca. 2.1 to 2.6 My
> interpreted from flowstones associated with the same deposit. We show that
> these previously dated flowstones are stratigraphically intrusive within
> Member 4
> and that they therefore underestimate the true age of the fossils.
>
>
> "Ecological reconstructions from the Member 4 fauna indicate a climate more
> humid than today, with mosaic grassland, savanna, and gallery forest,
> consistent with
> both C3 and C4 diets determined from fossil teeth (49). The Member 5 fauna is
> associated with a drying climate and far more grazers (49). "
>
> "savanna"
Forest.

littor...@gmail.com wrote:
> Op woensdag 29 juni 2022 om 07:30:19 UTC+2 schreef Primum Sapienti:
>
>>> Cosmogenic nuclide dating of Australopithecus at Sterkfontein, South Africa
>>> Darryl E Granger cs 2022
>>> PNAS 119 (27) e2123516119
>>> doi org/10.1073/pnas.2123516119
>
>> The REAL text, not what you made up
>> ... "savanna" ...
>
> :-DDD
> My little boy, you're the most idiotic of the kudu runners...
> Do you understand the word "flow-stones"??

"We show that these previously dated flowstones are
stratigraphically intrusive within Member 4
and that they therefore underestimate the true age
of the fossils. "

"intrusive", child...

> But the importance of this paper is that africanus did not evolve from afarensis, as anthropocentric PAs (kudu runners) like to believe.
> IOW, Pliocene "gracile" afarensis & africanus (aquarboreal) evolved in // to early-Pleistocene "robust" boisei resp. robustus.
>