[S26-2] Exploring connections between heat flow and tectonics II

[S26-2-03] Curie Depth Point of the Iberian Microplate. A thermal, compositional and tectonic perspective of its evolution

Juvenal Andres¹, Ignacio Marzan¹, David Marti¹, Imma Palomeras², Puy Ayarza², ^○Ramon Carbonell¹ (1.CSIC-ICTJA Inst. Earth Sciences Jaume Almera, 2.Department of Geology, University of Salamanca, Salamanca, Spain)

Thermal structure of the Iberian micro-plate is derived from magnetic data through the Curie-Depth Point (CDP) isotherm, which accounts for the depth at which ferromagnetic minerals become paramagnetic (~580 ºC). CDP modulates the surface heat flow through thermal conduction. Variations on the CDP thickness translate into heat anomalies most probably due to small scale tectonics. The CDP, the CDP derived thermal gradient with the Moho depth maps provide knowledge on the thermal regime. Within Iberia the isotherm is located at depths of 17 to 29 km beneath surface. This isotherm is shallow offshore, where the lithosphere is thinner. In continental Iberia, the Variscan domain reveals a deep signal, probably linked to thickening-extension processes during the orogeny, which an extensive emplacement of granites (in the Central Iberian Arc). This resulted in a very thermally conductive crust. The CDP at the Gibraltar Arc is consistent with the slab roll-back geodynamic model. Offshore the broad magnetization can be accounted for by proposing serpentinization of the upper mantle. Similarly, in the Atlantic margin, a relatively thick serpentine layer is interpreted, which is consistent with a hyperextended margin configuration (exhumed mantle has been sampled). The Mediterranean presents generalized serpentinitation in the Algerian Basin. Furthermore, correlations have been found between the CDP, thermal gradient and vertical ground motion, where subsidence is related to low thermal gradient and, null or small uplift implies high thermal gradient. (Research supports: CGL2014-56548-P, 2009-SGR-1595, CGL2013-47412-C2-1-P)