Resumen de Estimación de las tasas de erosión a largo y corto plazo basadas en termocronología (AFTD), cargas fluviales, volumen de sedimentos y erosión potencial. Ría de Vigo (Rías Baixas, Galicia)
Marta Pérez Arlucea, F. Clemente, A. Carter, D. González, Miguel Angel Nombela Castaño, Gonzalo Méndez Martínez
Denudation rates have been established using 4 different approaches, I) long-term rates (>106 yrs)based on thermochronology (AFTD), 2) theoretical calculations for potential erosion using DEMs,3) modern sediment yields from rivers loads, and 4) sediment volume (RamaIlosa Complex). AFTD results indicate gradients at or less than global average values of ~30°C/Km, and therefore place anupper limit from which to estimate the maximum amount of section lost to denudation. Thermal history modelling of the data show the samples experienced ~60°C of cooling over a 150 Myrperiod. Maximum geothermal gradient values of 30°C/km results in denudation rates of -13 m/Myr,which are consistent with those of potential erosion (25 m/My). AFTD data is consistent with potential denudation calculations. River loads and sediment volume calculations for short-term denudation rates gave much higher values. Considering the proportion of coarse to fine material, between 90 and 95% of the total sediments correspond to bed-load. An increment in sedimentation and denudation rates from 2000 yr BP to 500 y BP and from the last 500 yr may be interpreted by accelerated human influence. Pollen data suggest that climatic changes during the last 2500 years are not significant and vegetation changes are due to human influence.
