Jm. Soria et al., Quantitative subsidence-uplift analysis of the Bajo Segura Basin (eastern Betic Cordillera, Spain): tectonic control on the stratigraphic architecture, SEDIMENT GE, 140(3-4), 2001, pp. 271-289
The Bajo Segura Basin is located in the eastern Betic Cordillera, at presen
t connected with the Mediterranean Sea to the east. It has a complete strat
igraphic record from the Tortonian to the Quaternary, which has been separa
ted into six units bounded by unconformities. This paper is concerned with
the northern edge of the basin, controlled by a major strike-slip fault (th
e Crevillente Fault Zone, CFZ), where the most complete stratigraphic succe
ssions are found. The results obtained (summarised below) are based on an i
ntegrated analysis of the sedimentary evolution and the subsidence-uplift m
ovements. Unit I (Early Tortonian) is transgressive on the basin basement a
nd is represented by ramp-type platform facies. organised in a shallowing u
pward sequence related to tectonic uplift during the first stages of moveme
nt along the CFZ. Unit II (lower Late Tortonian) consists of shallow platfo
rm facies at bottom and pelagic basin facies at top, forming a deepening-up
ward sequence associated with tectonic subsidence due to sinistral motion a
long the CFZ. Unit III (middle Late Tortonian) is made up of exotic turbidi
tic facies related to a stage of uplift and erosion of the southern edge of
the basin. Unit IV (upper Late Tortonian) consists of pelagic basin facies
at bottom and shallow platform facies at top, defining a shallowing-upward
sequence related to tectonic uplift during continued sinistral movement on
the basin-bounding fault. Units V (latest Tortonian-Messinian) and VI (Pli
ocene-Pleistocene p.p.) consist of shallowing-upward sequences deposited du
ring folding and uplift of the northern margin of the basin. No definitive
evidence of any major eustatic sea-level fall, associated with the 'Messini
an salinity crisis', has been recorded in the stratigraphic sections studie
d. (C) 2001 Elsevier Science B.V. All rights reserved.