[meteorite-list] Alaska Big Wave at 12, 900? [ >230 m ] George Howard CosmicTusk.com blog: letter Carl L. Blanchard, report Robert D. Miller 1973, 2007 abstract: Rich Murray 2012.02.18

From: Rich Murray <rmforall_at_meteoritecentral.com>
Date: Sat, 18 Feb 2012 21:06:15 -0800
Message-ID: <CAHqJ8pY9dGZwAze9wa=mzL8tiTmaGjjpzz09c4gPZgBXsvJp3A_at_mail.gmail.com>

Alaska Big Wave at 12,900? [ >230 m ] George Howard CosmicTusk.com
blog: letter Carl L. Blanchard, report Robert D. Miller 1973, 2007
abstract: Rich Murray 2012.02.18


Alaska Big Wave at 12,900?

CosmicTusk.com blog George Howard

One of the fun things about blogging is that ideas and research will
often come in ?over the transom? from readers.
I was recently contacted by Mr. Carl Blanchard with what appears to be
long simmering evidence of an Alaskan mega-tsunami at our favorite
time period, the Pleistocene-Holocene transition.
Carl?s prose is disturbingly direct, but filled with intriguing
tid-bits of evidence.
Blanchard reports that deposits of marine shells and other oceanic
detritus found in the Juneau area stratigraphy were washed in from the
sea with a wave, rather than having been laid down over time.
Apparently, the accepted explanation for the shells is that the area
was once, not too long ago, under the sea, pressed won by glaciers,
and that the landscape was lifted from the ocean bottom to many meters
above present-day sea level when the glaciers receded.
However, according to Carl, there is no other traditional evidence of
glaciers having so recently effected the landscape in such a manner in
the area.

Blanchard does come out and say it, but his implication is that this
wave was so large that it was generated by an oceanic cosmic impact,
not by an earthquake.

I submit Blanchard?s telegramatic communication below for your review
and commentary.

UPDATE:
I found this paper which seem to represent the conventional opinion
regarding the marine deposits.
Seems there are three of them.
How does a single wave do that?

free full text on Scirbd:
Gastineau Channel Formation, a composite glaciomarine deposit near
Juneau, Alaska.
A description of the depositional environment and lithology of
diamictons of late Pleistocene and early Holocene age.
Robert D. Miller,
Geological Survey Bulletin 1394-C 1973 24 pages
[ 58.3 -134.4 ]

UPDATE II:
Check out this modern abstract on the Gastineau Chanel formation:

http://gsa.confex.com/gsa/2007AM/finalprogram/abstract_131294.htm

2007 GSA Denver Annual Meeting (28?31 October 2007)
Paper No. 87-10
Presentation Time: 8:00 AM-12:00 PM
UNDERGRADUATES PRODUCE GASTINEAU CHANNEL FORMATION WEBSITE FOR
IDENTIFICATION OF EARLY HOLOCENE MARINE SUBFOSSILS FROM AN UPLIFTED
GLACIOMARINE DIAMICTON, JUNEAU, ALASKA
CONNOR, Cathy L., BLEIDORN, Daniel M., KNUTH, Edwin, and THILENNIUS,
Carol, Natural Sciences, Univeristy Alaska Southeast, 11120 Glacier
Highway, Juneau, AK 99801, cathy.connor at uas.alaska.edu

Following the Last Glacial Maximum (LGM), the Gastineau Channel
Formation (GCF) was deposited between 12,000 and 10,000 years ago as
retreating tidewater glaciers calved icebergs into deepening fjords,
when rising sea level flooded the Juneau area (Miller, 1973, 1975).
The three facies of this formation contain ice-rafted debris that was
dumped into bluish-gray marine silt and sand.
These sediments provide the early Holocene matrix for subfossils of
marine mollusks, barnacles and foraminiferans.
This glaciomarine diamicton is exposed throughout the Juneau area at
elevations up to 230 m and indicates that LGM ice-loading, locally
depressed the crust well below worldwide sea level lowering of -120 m.

Field studies undertaken by University Alaska Southeast environmental
science program undergraduates, provided samples from throughout the
region.
Thilenius and Connor have identified the faunal constituents and
reconstructed their distributions and ranges.
Bleidorn created web accessible taxonomic keys and linked them with
photomicrographs to facilitate comparison of faunal constituents from
other early Holocene fjord deposits elsewhere in the region.
Knuth created a new GIS map that provides site location data, early
Holocene inundation visualization, and the areal extent of the facies
in the GCF.
The website enables visitors to key out species, locate
invertebrate-rich outcrop locations, navigate through GCF
stratigraphy, radiocarbon information, and learn about the areal
extent of these uplifted fjord sediments.

It is hoped that this website will be provide a useful, easily
accessible resource for Quaternary researchers working on post-LGM
records of climate variability in the region.
http://www.uas.alaska.edu/envs/gastineau_formation/index.html
2007 GSA Denver Annual Meeting (28?31 October 2007)


Hi, this article is intended to describe some aspects of the findings
related to the Pleistocene-Holocene boundary near Juneau, Alaska.
Carl Blanchard.

Marine Shells _at_ the Pleistocene-Holocene Boundary @ Juneau, Alaska

The RC date for a large chaotic array of Marine shells near Auke Bay,
 Alaska is quite close to one frequently used date for the PH
boundary.
The mix of shells included unexpected forms, scallops and deep water
barnacles are shells not observed on beaches in the area now --
however are still present in the inlet waters.
Several species no longer in waters of the area are found in the
Arctic Ocean now.
These shells reflect much colder conditions for the area in general. *******

RC dates are little changed for the much warmer water species on
Douglas Island near 10,000 years ago and all Arctic forms are absent.
Hiatella Arctica represents the Pleistocene cold water and Saxidomus
Giganteous indicates early Holocene conditions. *******

A large collection of shells from the site at 44 meters elevation was
washed and sorted into 14 piles of similar forms.
The most exotic were taken to the lab of the National Oceanic &
Atmospheric Adm. _at_ Auke Bay for specific identification.
Balanus Evermani typically found near 180 meter depth in the Juneau
area inlets was the most intriguing. *******

Ocean currents of unusual nature near the PH boundary in the Atlantic
Ocean near the Azores suggested a need for research.
One immense flow had dismembered and transported coral, typical of
shallow water, out to the Mid-Atlantic ridge.
The depositional position of the coral indicated only one event _at_
10,000 years ago had occurred.
RC dates and the rapid replacement of the cold water forms seemed to
indicate that the Juneau, Alaska area sites dating close to 10,000
years ago perhaps endured a similar surge from the Pacific Ocean.
Surging of the Ocean toward the north could help explain the rapid
warming of the area waters, especially as the Juneau area is far from
the open ocean. *******

The arid nature of the Juneau area during the last cold period likely
is a surprise.
Pollen analysis of samples from Montana Creek strata indicated
abundant sagebrush.
This harmonizes with the even more surprising fact that large areas
near Juneau have never once been glaciated [Auke Mt and central Lemon
Creek].
A thin protruding dike about 4 meters high is close to massive talus
blocks almost certainly indicating no glacial activity at that Lemon
Creek site in several hundred thousand years.
The high undisturbed stream gravel terrace along Lemon Creek provides
additional evidence that a large portion of this stream valley has
never been glaciated. One source claims a layer of excellently
preserved marine shells is found within the terrace along Lemon Creek.
Talus covered slopes surround the Auke Mountain area.
Erratics are believed absent from most of the plateau while some
streams have little total sediment.
A predecessor or ancestral glacier larger than Mendenhall left a large
pile of boulders as a terminus with no erratics beyond this point and
thick talus slopes soon appear.
The area seemingly has had no glaciers other than valley glaciers at
any time in the past.
Disjunct ?Yellow Cedar? occupies this area as additional indication
that this immediate area has not been disturbed by glaciation.
This information limits the possible glacial effects on sea level from
isostatic depression. *******

Marine shells encountered when the Treadwell ditch and flume was
constructed are at the highest reported elevation of the Juneau area
at 164 meters. Microfossils reported at 230 meters near the Montana
Creek headwaters is the highest known evidence indicating former ocean
level.
Some rebound, hard to fully evaluate, has occurred in the Juneau area
however the nature of the ice before the event sharply limits the
maximum amount. Investigators of the USGS rejected the all
encompassing and terrain covering ice sheet typically visualized for
the late Pleistocene in the Juneau area.
It was learned that many area glaciers were not even reaching the
tidal area of the ocean.
Aridity of the area revealed by pollen analysis supported this conclusion
[ the author was credited with the discovery of the layer containing
organics permitting the pollen analysis ]
The strata analyzed for pollen also indicates that the ocean level
was similar to the present level, or lower, in the Pleistocene before
39,000 years ago.
McGinnis [ tributary of Montana Creek ] creek upstream from the
organic layer has the 2nd highest elevation [130 meters] for reported
occurrence of marine shells. Consensus likely exists among
investigators that the Juneau high level marine phase was short lived
rising from and returning to a much lower level in no more than a few
thousand years.
The highest deposits are poorly indicated apparently without a beach
phase while unexpected forms [worm tubes, etc.] are present.
The organic layer also has a level layer of volcanic ash [layers above
the ash were sampled].
The marine shells at McGinnis Creek indicate that the associated
diamicton achieved elevations that overlie the earlier land based
deposits.
The site of the marine shells is now about 10 meters higher than the
pollen containing layer.
Immediate dominance of Pine Pollen for a basal site investigated at
the head of Montana Creek suggests that the Lodge Pole Pine remained
throughout the Pleistocene on the Auke Mountain Plateau where this
tree species still unexpectedly largely dominates the higher
elevations.
Peterson Lake, thought to be unrelated to glacial processes, is on the
plateau -- therefore likely can confirm the continuous presence of
pine trees by coring and pollen analysis. *******

Peterson Lake is shielded from all glacial events and at 250 meters in
elevation apparently can test the surge thesis.
The highest reported PH oceanic high stand level for the Juneau area
was indicated by foraminifera _at_ 230 meters at the head of Montana
Creek [ Peterson Lake is 4 km from this site ] *******

A significant mystery involving marine shell deposition evolved 27 km
Northwest of Peterson Lake near the Lynn Canal seacoast.
It was mentioned to the author during a flight over the area of
Bridget Cove that a sand deposit was discovered during road
construction as the work approached the watershed divide.
Sand was not something expected in that bedrock dominated coastal area.
Opportunity to inspect this site was delayed for a year or more when
some of the anomalous sand was collected.
When closely inspected at a later time the ?sand? was entirely
pulverized shells, although not a single shell fragment was noted
while briefly at the site [ the deposit is about 3 meter thick & 60
meters above sea level ]
How could such a large deposit become so thoroughly pulverized [ the
rocky coastline suggests large eddies or vortices as one possibility
]? *******

Indication of great pressure at a date and place where no ice was
possible is another mystery although a suggestion of cementation is
introduced by the highly alkaline water of this part of Douglas
Island.
The description indicating dense packing suggests high pressure of
uncertain origin perhaps related to the depth of the water.
Diamicton formation, as described by appropriate scientists, is
regarded as a low pressure process dominated by drifting ice.
Shell collections from northeastern Douglas Island are predominately
of early Holocene age. *******

It is likely that no other place is as profoundly dominated by
Pleistocene -- Holocene transition events as the Juneau, Alaska area,
perhaps the Puget Sound area is a close analogue.
The rapid time frame is less apparent at Puget Sound and the evidence
indicates an implausible confusing extreme short term oscillation of
sea levels.
The lower Fraser River was above sea level and ice free near 18,000
years ago however was destined to record the highest level for the
subsequent marine invasion perhaps due to delayed rebound.
Diamicton with articulated marine shells transgressed land areas while
glacier ice was claimed absent near Bellingham, WA.
Events of the Puget Sound area were also rapidly unfolding -- however
are apparently slightly earlier than indicated at Juneau.
The Puget Sound area had a dry climate before the onslaught of glacial
events perhaps, in part, due to a lower sea level causing marine
climatic effects to be more distant.
The sea level claimed for Juneau is diametrically opposed by the
general claim of far lower sea levels for that time period.
Ice sheet loading is not a viable explanation for this discrepancy for
the sea level at Juneau.
Introduction of the diamicton sediments have not yet been demonstrated
to result from the terminal glacial processes although the timing
intuitionally suggests some relationship.
Overridden land based RC dates should be earlier than the event --
however one of those at Bellingham, Wa. [10,370 years BP] is well
within the range at Juneau.
28 January 2008 Carl L. Blanchard slight revision & corrections
have been made.
February 17th, 2012
Received on Sun 19 Feb 2012 12:06:15 AM PST