Geoscience Reference
In-Depth Information
Fig. 9.19
The chronology for
mega-tsunami in Northwestern
Australia over the past two
millennia. The panel was
constructed using the same
Fifteen dates have been used
here. The dips are an artifact of
age reversals in radiocarbon
chronology
Northwestern
Australia
1.0
0.5
0.0
0
500
1000
1500
2000
Year
an impact event at this time from North America. Abbott
et al. (
2010
) found impact glass, an impact spherule and
marine microfossils in a bog core at Cornwall, New York
that has been radiocarbon dated around AD 1006 ± 65.
There are also Micmac legends in Canada referring to such
an event (Nowlan
1983
). This collection of records suggests
a significant cosmogenic event occurred in 1014 affecting a
number of locations around the North Atlantic Ocean. The
suspected source area lies in the middle of the Atlantic
Ocean above 40 latitude (Haslett and Bryant
2008
; Abbott
et al.
2010
).
describing coherent catastrophism was severely criticized
by Chapman (
1996
), while Kristan-Tollmann and Toll-
mann's (
1992
) Deluge Comet hypothesis
8,200 ± 200 years ago received harsh criticism and rejec-
tion (Deutsch et al.
1994
). The idea of a comet crashing into
the Indian Ocean May 10, 2807 BC and producing a mega-
tsunami was considered extra-ordinary and the ''term
'chevrons' should be purged from the impact-related liter-
ature'' (Pinter and Ishman
2009
). Chevrons on Madagascar
were also clearly denied by Bourgeois and Weiss (
2009
)in
the title of their publication, ''Chevrons are not mega-tsu-
nami deposits''. Both papers ignore the fact that they are
presence worldwide and have a fabric that is not wind-
blown (Fig.
3.9
) (Kelletat and Scheffers
2003
; Scheffers
et al.
2008a
). Much of the criticism for cosmogenic tsunami
concerns this author's collaborative work along the New
South Wales coast (Felton and Crook
2003
; Goff et al.
2003
; Courtney et al.
2012
). Surprisingly, while storms are
often suggested as an alternative, some of the authors have
published their own research on paleo-tsunami along this
coast that clearly supports the evidence and chronolo-
gies—particularly for the Mahuika Comet Event—pre-
sented above (McFadgen
2007
; Switzer et al.
2011
). These
criticisms, while posing alternative explanations in some
cases, but often none otherwise, trivialise three aspects of
the tsunami hazard. First, the signatures described in
occurrences. They form a suite of signatures that charac-
terizes the geomorphology of long sections of coastline in
many countries as outlined in this topic. Second, these
signatures have been published under peer review in highly
regarded Geology journals. Third, this evidence in the case
9.7
Criticisms of Legendary Events
The invoking of Late Holocene comet impacts, let alone the
possibility of the generation of mega-tsunami, poses a
problem for Science, which is cultured to a minimalism
point of view—namely nothing changes suddenly. This is
especially true for geological discovery. The best example
of this is the invective criticism that occurred in the 1960s
with the proposition of continental drift. This topic has been
dedicated to J Harlem Bretz who proposed that the Scab-
lands of Washington State were formed by catastrophic
flooding generated by outbursts from glacial Lake Missoula.
The criticisms were polemic; but Bretz stood his ground and
was eventually proved correct (Baker
1981
). Some of our
evidence for catastrophic tsunami parallels his. The ideas
put forward by this author and those of others supporting
coherent catastrophism, comet impacts in the last
10000 years, or the role of cosmogenic tsunami in shaping
coastlines
is
no
different.
Duncan
Steel's
(1995)
book
