The Cenozoic Malaguide Basin from Sierra Espuña (Murcia, S Spain): An Example of Geological Heritage

Abstract

The Cenozoic Malaguide Basin from Sierra Espuña (Internal Betic Zone, S Spain) due to the quality of outcropping, areal representation, and continuity in the sedimentation can be considered a key-basin. In the last 30 years, a large number of studies with very different methodological approaches have been done in the area. Models indicate an evolution from passive margin to wedge-top basin from Late Cretaceous to Early Miocene. Sedimentation changes from limestone platforms with scarce terrigenous inputs, during the Paleocene to Early Oligocene, to the deep basin with huge supplies of turbidite sandstones and conglomerates during the Late Oligocene to Early Miocene. The area now appears structured as an antiformal stack with evidence of synsedimentary tectonics. The Cenozoic tectono-sedimentary basin evolution is related to three phases: (1) flexural tectonics during most of the Paleogene times to create the basin; (2) fault and fold compartmentation of the basin with the creation of structural highs and subsiding areas related to blind-fault-propagation folds, deforming the basin from south to north during Late Oligocene to Early Aquitanian times; (3) thin-skin thrusting tectonics when the basin began to be eroded during the Late Aquitanian-Burdigalian. In recent times some works on the geological heritage of the area have been performed trying to diffuse different geological aspects of the sector to the general public. A review of the studies performed and the revisiting of the area allow proposing different key-outcrops to follow the tectono-sedimentary evolution of the Cenozoic basin from this area. Eight sites of geological interest have been selected (Cretaceous-Cenozoic boundary, Paleocene Mula Fm, Lower Eocene Espuña-Valdelaparra Fms, Middle Eocene Malvariche-Cánovas Fms, Lowermost Oligocene As Fm, Upper Oligocene-Lower Aquitanian Bosque Fm, Upper Oligocene-Aquitanian Río Pliego Fm, Burdigalian El Niño Fm) and an evaluation has been performed to obtain four parameters: the scientific value, the educational and touristic potential, and the degradation risk. The firsts three parameters obtained values above 50 being considered of “high” or “very high” interest (“very high” in most of the cases). The last parameter shows always values below 50 indicating a “moderate” or “low” risk of degradation. The obtained values allow us considering the tectono-sedimentary evolution of this basin worthy of being proposed as a geological heritage.

A Python Application for Visualizing an Imbricate Thrust System: Palomeque Duplex (SE, Spain)

“…It is surrounded by the towns of Mula and Bullas to the north, Aledo and Totana to the south, Zarzadilla de Totana to the west, and El Berro to the east, with Pliego located in a center position (Figure 1B). Geologically, this area belongs to the Malaguide Complex from the Internal Betic Cordillera [32][33][34][35][36][37][38][39][40]. The Internal Zone of this cordillera usually shows metamorphic rocks in the lower Nevado-Filabride and Alpujarride complexes [41].…”

“…The Internal Zone of this cordillera usually shows metamorphic rocks in the lower Nevado-Filabride and Alpujarride complexes [41]. The upper Malaguide Complex is the only one showing a sedimentary basement (sometimes epimetamorphic) and cover [35][36][37][38][39][40][41][42].…”

“…The area mainly shows the Mesozoic-Cenozoic cover (with a thin sheet of Paleozoic basement) from the Malaguide Complex [38][39][40]. The entire area is structured in the Mula-Pliego Depression (a synclinorium with minor structural highs, related to fold-thrust) to the north (Figure 1B), followed, to the south, by the Sierra Espuña s.s. (an antiformal stack) [32][33][34].…”

“…The area has a quite continuous sedimentary record and outcrops of good quality from the entire succession, so that a large number of papers have been published in the last three decades ( [32][33][34][35][36][37][38][39][40] and references therein). In particular, the Paleocene to Early Miocene tectono-sedimentary evolution has been the subject of numerous research papers, making this basin a key site for understanding the Cenozoic tectono-stratigraphy of the region [38].…”

“…This new research aims the application of Python libraries to construct 3D structural and stratigraphic representations of an imbricate thrust system, using, as an example, the Palomeque Duplex from the Malaguide Complex [32][33][34] in the Mula-Pliego Depression from the Sierra Espuña area [35][36][37][38][39][40] in the Murcia province (SE, Spain: Figure 1). The methodology presented in this article can be exported to other geological systems.…”