Colleagues -
The International Commission on Stratigraphy (ICS), under the auspices of
IUGS and ICSU, is revising the Geological Time Scale. A proposed revision
of great consequence to the Quaternary community is an extension of the
Neogene System to the present. The Pleistocene and Holocene would be
retained as Series, but the Quaternary would be eliminated as a System. An
argument made by ICS is that the "Quaternary" and "Tertiary" are archaic
terms. Elimination of Quaternary as a System is clearly a highly charged
issue, but ICS seems determined to make the change, whether or not
Quaternarists agree.
INQUA does not accept the elimination of the word "Quaternary" from the
Geological Time Scale. Accordingly, its Commission on Stratigraphy and
Geochronology has suggested a compromise to the INQUA Executive Committee
that may or may not be acceptable to both the larger Quaternary community
and ICS (see following letter and proposal from Brad Pillans). The gist of
the proposal is to define a Quaternary Subsystem that encompasses the
present Pleistocene and Holocene Series, as well as the Gelasian Stage
(2.6-1.8 Ma). Under this proposal, the boundaries of the Pleistocene and
Holocene would remain unchanged.
The INQUA Executive Committee ask for your feedback on this important
issue. Please send your comments to John Clague (jclague@sfu.ca) and Brad
Pillans (brad.pillans@anu.edu.au).
INQUA Executive Committee:
John J. Clague
Nicholas Shackleton
Peter Coxon
Margaret Avery
Allan Chivas
Jan Piotrowski
Denis-Didier Rousseau
An Zhiseng
___________________________________________
Dear Colleagues,
The Geological Time Scale (GTS) is one of the great achievements in Earth
Sciences. Recent revisions, and proposed revisions, are part of the ongoing
mandate of the International Commission on Stratigraphy (ICS) - see
www.stratigraphy.org.
One of the proposed revisions of the GTS is to extend the Neogene System
(Period*) up to the present, thereby subsuming what is currently the
Quaternary System (Period). While some may see this as a threat to the
Quaternary, I see it as a wonderful opportunity to redefine the Quaternary
in the way that we have wanted for some time, namely to extend the base
downwards from 1.81 Ma (Plio/Pleistocene boundary) to 2.6 Ma (base of
Pliocene Gelasian Stage).
Let me speak plainly when I say that we (INQUA) have little hope of
retaining the Quaternary System, above the Neogene System, as it is at
present. The weight of support is too great, from within ICS, for extending
the Neogene up to the present. Furthermore we have no hope of changing the
Plio/Pleistocene boundary; we tried that in 1997-98, resulting in a most
acrimonious debate between INQUA and ICS.
I believe that our best, and only reasonable course of action, is to grasp
the opportunity presented to us, and redefine the Quaternary as a Subsystem
within the extended Neogene System, with base at 2.6 Ma. Indeed, I have
been asked to submit such a proposal to ICS. The proposal below is a draft
for comment/discussion and, perhaps, for endorsement by INQUA. As
recommended by ICS, I have tried to keep the document short and
to-the-point.
A strength of the proposal, I think, is that it decouples the base of the
Quaternary from the "blood sweat and tears" of the Plio/Pleistocene
boundary.
The views expressed are my own, but I sense that they will be widely
supported by Quaternary scientists. After all, this is a chance to extend
our time domain by 800,000 years!
To reiterate, this may be a once-in-a-lifetime opportunity - we are
unlikely to get another opportunity to define the Quaternary the way we
want it.
Brad Pillans, President INQUA Stratigraphy & Chronology Commission
* "Period" is the geochronologic unit equivalent of the chronostratigraphic
unit "System".
PROPOSAL TO REDEFINE THE QUATERNARY
In the revised geological time scale (GTS2004) Lourens et al. propose to
extend the Neogene System (Period) up to the present, thereby making the
Quaternary System (= Pleistocene + Holocene Series) redundant. See Figure 1.
Here I propose that the Quaternary be redefined as a Subsystem (Subperiod)
of the Neogene, and that its base be defined at the base of the Pliocene
Gelasian Stage at 2.6 Ma (GSSP ratified - Rio et al. 1998. Episodes 21,
82.). After recent discussions by the ICS executive, in consultation with
the IUGS executive, they have requested that the various formal
stratigraphic groups of ICS and INQUA be asked to consider the proposal.
In support of the proposal for a Quaternary Subsystem (Subperiod), I note
the following:
* There is overwhelming support from INQUA members, who I have talked
with, to retain the Quaternary as a formal chronostratigraphic unit.
* There is precedence for naming Subsystems in the GTS, specifically
the Mississippian and Pennsylvanian Subsystems of the Carboniferous.
* Redefinition of the Quaternary will make use of an existing GSSP
(Gelasian Stage).
* Decoupling the base of the Quaternary from the Plio-Pleistocene
boundary (1.8 Ma) would, I believe, bring an end to the long-running
arguments over the position of the Plio/Pleistocene boundary.
* A majority of INQUA members appear to favour a "long" Quaternary (2.6
Ma) over a "short" Quaternary (1.8 Ma). In essence, the preference for a
"long" Quaternary reflects perceived continuity of character over that
time. For example, around 2.6 Ma, Chinese loess deposition becomes
widespread and is substantially different in character to the underlying
Red Clay (e.g. Ding et al. 1997. Quaternary International 40, 53).
* Around 2.6 Ma, deep sea oxygen isotope records show the culmination
of a series of cycles of increasing glacial intensity, also associated with
the first major inputs of ice rafted debris to the North Atlantic. For many
this marks the beginning of the "Quaternary ice ages". It also marks a
change from precession-dominated to obliquity-dominated climate forcing.
In summary, the extension of the Neogene System (Period) upwards provides
an ideal opportunity to redefine the Quaternary, as a Subsystem (Subperiod)
of the Neogene. The proposal for a Quaternary Subsystem is consistent with
popular usage, does not require a new GSSP, and will end the arguments
about the Plio/Pleistocene boundary.
Sacred Mayan stone uncovered
US archaeologists working in Guatemala have discovered a sacred stone covered with inscriptions dating to the end of the classic Mayan civilisation.
Researchers from Tennessee's Vanderbilt University and the National Geographic Society in Washington discovered the stone while excavating one of the largest Mayan royal palaces, located in Cancuen, central Guatemala.
It was built between 765 and 790 AD by Mayan ruler Taj Chan Ahk.
The archaeologists hope to use the discovery to glean important information about the events of the final 30 years of the Mayan era.
More detail At National Geographic's site.
Obvious statement alert: Do You Judge People By Their Cars? Professor Says Everybody Does It
MADISON, Wis. -- Everyone makes judgments about others based upon their hair, body shape and even their car, according to lesson in a University of Wisconsin archaeology class.
Archaeologist Sissel Schroeder gave students in her Anthropology 112 course the assignment of surveying a small number of cars in designated campus parking lots and using what they observed -- make, model, age, condition -- to draw conclusions about the gender and social standing of the owners.
"In archaeology, when you are dealing with the prehistoric world, there is no reality to check it against, so our inferences are always subject to reinterpretation," Schroeder said.
Archaeologists find emperor's marble head in Petra
AMMAN: French archaeologists have unearthed a perfectly preserved head of the Roman Emperor Marcus Aurelius in the ancient Nabatean city of Petra south of Jordan, the head of the mission said Thursday.
"A monumental white marble head, in excellent condition, belonging to a statue the Emperor Marcus Aurelius was found in Petra by French archaeologists," Christian Auge said.
The head of the 2nd century Roman leader, who was also known as the "good emperor" or the "philosopher-king," was found in the Qasr al-Bint area of Petra, a Nabatean city famous for its rose-red temples dug into rock.
Courtyard archaeology
I awoke to a cool, late spring morning with the resolve to reclaim some lost property.
Over the next few days, my efforts uncovered about 100 square feet of courtyard that had been taken over by matted vines, roots and composted leaves. The project yielded six wheelbarrow loads of dirt, which I used to make a raised bed for herbs and ornamentals.
There are people who pore over land records in courthouses looking for unclaimed property. Instead of a computer, I laid claim with a grain shovel, hoe and hatchet. The work was immensely satisfying.
Okay, not exactly archaeology in the strictest sense. But a nice article nonetheless. Call it lifetime-scale archaeology.
Dam archaeologists! Experts to examine dams' histories
FREDERICKSBURG, Va. -- Archaeologists will examine the history of the Embrey Dam and a wooden dam upstream from it before contractors begin dismantling the structures in July.
The $12,000 project will gather existing documents about the dams, including studies the Army Corps of Engineers and Fredericksburg City Council have commissioned over time.
"These are structures, so they are in the realm of archaeological historians," said Kim Zawacki, an archaeologist and principal investigator with Cultural Resources Inc. of Fredericksburg.