Arkell.1956.Jurassic..

244 THE IBERIAN PENINSULA
one unbroken limestone and shale series. The Middle Jurassic is but
feebly developed but shows a little more variety, for though usually
limestone, the Bathonian in some places contains sandy elements. The
Upper Jurassic consists almost entirely of nodular limestones (fausses
breches, Knollenkalk), often a mere 30-50 m. thick but reaching a maximum
of 350 m.; the Tithonian is strongly developed (up to 250 m.). The
Oxfordian and Kimeridgian of the Andalusian facies, from a few metres
to 100 m. thick, contrast spectacularly with the 1500 m. of the same stages
in their Lusitanian facies in Portugal. Besides nodular structure, a
speciality is red colouring, which recurs at several horizons, not only in
the Upper Lias, which provides, as elsewhere in the Mediterranean region,
FIG. 28.—Tectonic sketch-map of the Betic Cordilleras. After Fallot, 1948.
the typical Ammonitico rosso, but also in the Upper Jurassic and locally
in the Lower Lias. The fauna consists almost exclusively of cephalopods,
among which are a high proportion of Phylloceratids and Lytoceratids
at nearly all levels.
The Andalusian (or, better, Mediterranean) facies has often been called
bathyal, but several facts suggest that the sea cannot have been deep. The
red colouring is derived from iron oxides intrinsic to the deposits, and this
presupposes aeration of the bottom; the microscopic composition of the
limestones is not that of deep-sea sediments; and the typical Tithonian,
Kimeridgian and Upper Oxfordian nodular limestones are all locally
transgressive (Fallot, 1934, p. in). Nevertheless, the lack of terrigenous
sediments indicates deposition in a tranquil and open sea a considerable
distance off-shore.
The change of facies from the epicontinental or west European type to
the Andalusian or Mediterranean type takes place abruptly along an
irregular line running from the southern edge of the Neogene basin of
the Guadalquivir eastwards to the sea at Alicante, and is found again
http://jurassic.ru/