260 Apuntes del Alcázar de Sevilla
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different sandy layers from a flash flood that elevated the basement
level in successive layers more meter and a half warns. On these fill-
ers again a new episode of collapse of structures in the same direc-
tion detected. At the eastern end of the gallery they are located the
remains of a large fluted among many apparently overturned stones
from a height slightly higher, perhaps belonging to the porch of the
adjacent square. These blocks lie between a powerful layer of sand
and shells of irregular thickness (Figure 38).
Mixed with sediment and on the blocks and quadrants of walls and
columns, numerous remains of pavements of opus signinum, deco-
rated architectural elements, fragments sectile marble, tiles, plaster
polychrome Murari, tegula tiles, bricks and adobes were located whose
membership structures the top of the building seems beyond doubt.
The silting reached to exceed threemeters thickof sediments arranged
in very clear layers where it is detected countless graves of plundering
from late levels located to a 10snm level, from the 10.50 level.
The main result of this event was the final abandonment of the re-
publican level (7snm) not to return to constructive activity detected
in two centuries. When such activity is recovered in the V century
and will become the level 10. At that time definitely the memory
disappears in this area of the original natural slopes.
Sedimentary studies divide this process in two consecutive stages:
• Initially, towards the end of a long period of stability between
the late second century AD and early third century AD, could be
frame a possible high-energy event leading to the deposition of
sands with very abundant seashells in the Patio de Banderas and
is followed by the collapse of Roman imperial structures. Profile
stored in the crypt these fillers correspond to the lower gray level
arranged on the Roman pavement.
• Subsequently, a stage of slope instability occurs. Consistent or
not with the aforementioned “high-energy event,” but going
immediately after a new process of destabilization of the slopes
occurs on the escarpment of the river terrace deposits result-
ing coluvionares basically consist of eroded sediment horizons
surface of brown soils to which archeological remains deposits
and next structures are incorporated. These deposits come to
fill rooms and develop bottom-side current Alcazar Gardens.
However, it is not a stage that is only detected in the vicinity of
the Real Alcázar, since identical processes have been described
between the C/ Butron and C/Gallo. In the profile stored in the
crypt these fillers correspond to the reddish upper level.
Regarding the high-energy event, Barral and Borja describe a sand
reservoir with abundant small seashells arranged on the pavement
of the Roman Imperial period. The study of materials and three ra-
diocarbon dates confirm a chronology ranging from the last decades
of the second century and early third century AD to the deposition
of the sands. It is relevant the elevation they appear, located around
+7 m, while the floodplain Roman Imperial period (if AD) stood at
levels of +2 to +4 in the Guadalquivir (Barral, 2004), and +3 to +4
m in Tagarete (Borja and Borja, 2007). This represents a drop of 3-5
m above that plain, with the effect of protection from river flood-
ing involved. It is necessary to consider the influence of the Gua-
dalquivir River, which is still in the vicinity of the current cathedral
in transit s.II the third century, or more on the Tagarete stream. Not
kept rolling sands, perhaps because of his post-depositional removal,
perhaps because they are in an urban context, their sedimentologi-
cal interpretation is difficult. However, considering that the fluvial
influence has had to overcome the 3-5 m separating the floodplain
of the dimension to the sandy deposits that are described, but not be
interpreted the influence of a high-energy event.
The high presence of shells of marine molluscs could even lead to
think as a possibility, about the influence of a tsunami. Studies pub-
lished about tsunamis in historical times have widely reported of
various “extreme wave events” detected in the mouth of the Gua-
dalquivir around the Roman period. It is highlighted the one dated
to ca. 2000 cal BP (Ruiz et al., 2004), interpreted as associated with a
tsunami (Lario et al, 2010), while another described in ca.1500 1700
cal cal BP or BP (Ruiz et al., 2007; Vidal Rodriguez et al, 2008). The
latter, which is close in timing to our sandy deposit with seashells,
is being considered as a EWE with limited impact (Lario et al, 2010).
Therefore, with the information that we have today, these sand de-
posits could be interpreted as corresponding to a deposit of alluvial
origin, having to wait for the new analyses yet to perform to agree
with the circumstances that led to its formation.
After the event described the collapse of the Republican Roman
structures occurs, upon which has been described a set of abundant
deposits silt-clay matrix and a striking reddish-brown color that ap-
proximates the color of brown soil horizons above described to the
roof terrace. Archaeological research gives them Roman Imperial
chronologies (III-II century AD with intrusions of materials V cen-
tury because plundering removals), arranged between levels rang-
ing from +6.30 +8.50 m to m. These sediments are characterized by
abundant fine matrix, mainly silty clays armed incorporating clay
and in some cases songs carbonate nodules. Both silt-clay matrix,
as the reddish-brown clay and armed edges can inform the nearest
source of sediment, specifically the erosion of the upper horizons
of the brown soils of river roof terrace. This could be explained as
the result of a process characteristic coluvionamiento of troughs and
scarps of river terraces. That is, the removal and immediate depo-
sition on the escarpment of the terrace (natural or anthropogenic)
surface formations of the roof of the same by a runoff, not chan-
neled, and favored by the high slope of the escarpment leading to a
colluvium slope. The presence of various structures in this sector of
the Patio de Banderas should condition the natural development of
colluvium, provided that instead of downhill with the characteristic
sloping deposits depending on the slope, passing colmatar stays ir-
regularly placed at heights more low.
The main consequence of this flood process will be the rising of lev-
els by in about three meters with respect to the Republican base-
ment floors. In other words, if until the second century A.D. there
was a steep slope to the south architecturally corrected thanks to
Roman planning, from the third century AD the land from all over
this sector will be stabilized at a height above 10 snm and since then,
any constructive activity, such as the ones from the centuries V, VII,
XI and XX, will only adapt to a flat terrain, being superimposed until
reaching the current level of 12’40 m. asl.
Late-antique remains. Late V century.
In the archaeological profile kept in the crypt two murarias intru-
sions penetrating the sedimentary levels belonging to that flood are
appreciated. They are the structures of small masonry, which formed
part of the foundation of two separate walls, and disappeared, the
building slow old dated to the late fifth century The first overlaps the
