6. Rotational kinematics of the Boltaña anticline - Instituto Geológico ...

Boltaña kinematics Mochales, 2011
limestones (Alveolina Limestone) and marly limestones (Millaris and Metils Fms., Van Lunsen 1970).
A deltaic sequence of marls, siltstones and sandstones (Yeba Fm., Van Lunsen 1970), overlies the
previous sequence. The Boltaña Fm. represents the upper unit of the Ypresian (Cuisian) succession
and consists of shallowing upward heterolithic sequences of sandstones, and bioclastic sandy
limestones (Barnolas et al. 1991). These units crop out in the core of the Boltaña anticline (Figure 12).
The top of the Boltaña Fm is a flooding surface resulting from a drowning unconformity above the
shelf (Barnolas and Teixell, 1994) that preludes the sedimentation of distal carbonate ramp marls of
the San Vicente Fm (De Federico, 1981).
The Paules and La Patra Mbs, from the San Vicente Fm, crop out in the western limb of the
Buil syncline. The lower part of the Paules Mb (De Federico, 1981) corresponds to a retrogradational
ramp, which is evidenced by the abundance of stratigraphic truncations. This retrogradational
character turns to progradational in the upper part of the Paules Mb (Barnolas et al., 1992). The
transition to La Patra Mb (De Federico, 1981) is located in a flooding surface with glauconite followed
by a slope carbonate breccia (Coscollar level, Barnolas et al., 1991). This carbonate breccia slope
apron develops at the foot of an erosional truncation in the shallow carbonate Guara Fm (Barnolas et
al., 1992), see figure 12.
Figure 12a.
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