The Valanginian is marked by a major platform demise inducing a hiatus
in the northern Tethyan neritic carbonate record from the top of the
lower Valanginian to the lower Hauterivian. New biostratigraphic and
chemostratigraphic data from the Ollioules section (Provence Platform,
southern France) are presented here, demonstrating that a large part of
the upper Valanginian is preserved in an inner platform environment. The
thick, upper Valanginian, aggrading carbonate succession is observed in
an aborted rift domain, implying relatively low subsidence. In this
context, a relatively long-term sea-level rise was required to sustain a
keep-up style of carbonate production. Like the Apulian Platform, the
remarkable preservation of the Provence Platform may have been favored
by its remoteness from terrigenous source areas, as suggested by the low
clastic inputs and low P-accumulation rates. Two main biotic community
replacements are observed in Ollioules. The first saw the development of
abundant microbialites and algae at the onset of the late Valanginian. A
Tubiphytes concentration occurred during the coolest climatic conditions
and the transition towards arid conditions, whereas the subsequent
Lithocodium-Bacinella and orbitolinids assemblages developed under low
nutrient conditions during a warmer interval. Both assemblages may have
been triggered by increased alkalinity. The second community replacement
saw the installation of coral- and rudist-dominated communities during
the latest Valanginian to early Hauterivian. They indicate a change to
oligotrophic, open marine conditions. Six medium-scale sequences have
been defined in Ollioules, indicating short-term
transgressive-regressive trends superimposed on a long-term
transgression. Low nutrient inputs and relatively low subsidence in an
aggradational context may explain the survival of the isolated Provence
Carbonate Platform during a time of widespread drowning episodes and
platform demise in the northern Tethyan domain. (c) 2012 Elsevier B.V.
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