19th Dec., 2009
Dear WM, I found an old paper entitled “The
Method of multiple working hypotheses” by T.C. Chamberlin
published in Journal of Geology, 5 (1897) 837–848.
It has close bearing on current debates on the mantle
plume hypothesis. The mantle plume hypothesis has often
been linked to the origin of oceanic island basalts
(OIB) and continental flood basalts (CFB), with potential
implications for the composition of the lower mantle
and even the core-mantle boundary layer. The debates
centered on this issue closely mirror imperfections
of our knowledge of mantle geochemistry. The issue
of the origins and evolutionary mechanisms of oceanic
and continental basaltic magmas is a vast subject.
For anyone who wants to argue for/against the mantle
plume hypothesis, it is necessary to clarify the positions
of those said to hold divergent views.
The supposed divergence here includes not only acceptance/rejection
of the evidence for the existence of mantle plumes
(and the implications for the geochemical nature of
their postulated ultradeep mantle sources), but also
confidence/doubt in the applicability of the plume
hypothesis to the origin of continental mafic rocks.
The view that this position is somehow subjective may
arise from confusion between objective reality (the
existence of geochemical varieties of OIB and CFB )
and a human construct (a cherished but subjective model
for the origin of observed features). The problem appears
to be one of “academic affection” in the
method of multiple working hypotheses (Chamberlin,
1897). On one hand, when a model has assumed the status
of reality in the minds of its adherents, the whole
system under discussion is viewed in the context of
the model and thus there is great resistance to any
attempt to challenge it.
Cruises
