Post-tectonic landscape evolution in NE Iberia using staircase terraces: Combined effects of uplift and climate

Abstract

39River incision into bedrock resulting from the combined effects of tectonic uplift and 40 climate governs long-term regional landscape evolution. We determined spatial and 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176

Terrestrial 10Be and electron spin resonance dating of fluvial terraces quantifies quaternary tectonic uplift gradients in the eastern Pyrenees

“…In the Cinca watershed, where 10 levels have been identified in total, only the two most elevated terraces (Qt1 and Qt2) are older than the BrunheseMatuyama reversal, i.e. older than 781 ka (Lewis et al, 2009(Lewis et al, , 2017. On the G allego, with 12 tread levels in the downstream region, the six most elevated terraces (T06 to T01) are also reportedly older than 781 ka (Benito et al, 1998(Benito et al, , 2010.…”

“…midway up the terrace sequence as in the Segre watershed. Terrace levels attributed to MIS 6 on the G allego River, with 6 OSL ages ranging from 181 ± 13 and 133 ± 10 ka, refer to a system displaying much less relative relief (30e50 m) between the treads of the different terraces (Lewis et al, 2009(Lewis et al, , 2017Benito et al, 2010). Finally, the lower terraces form between 2 and 6 strath terraces distributed within a band of relative relief ranging between 20 and 60 m (Fig.…”

Geomorphic and tectonic implications of the endorheic to exorheic transition of the Ebro River system in northeast Iberia

“…Deciphering how much the fluvial dissection progressed, how far the regional waves of incision propagated upstream, and how close from a steady state the long profiles are under the new postcapture base level will provide clues on how the landscape evolved in the basin and how ancient the capture was, especially when comparing it with neighbouring basins (e.g., Duero basin; Antón et al, 2012Antón et al, , 2018. In this regard, geomorphic and geologic studies carried out at different locations in the Ebro catchment suggest the existence of prominent knickpoints in the profiles of some of the most important tributaries of the Ebro River; these might reflect that the sectors upstream of these knickpoints graded to a base level that was different from the present one (Stange et al, 2013;Scotti et al, 2014;Lewis et al, 2017). Previous investigations also proposed that uplift movements affected the catchment throughout the Quaternary and helped to create and preserve the terrace staircases of the Ebro tributaries (García-Castellanos and Larrasoaña, 2015;Giachetta et al, 2015;Stange et al, 2016).…”

“…According to Stange et al (2013), terrace formation seems to be related to the synchronous action of Quaternary climatic oscillations and tectonic uplift. Aggradation phases are linked to the delivery of large volumes of sediment, originating in the surrounding reliefs as a result of the expansion of glacial and/or periglacial conditions during the colder phases of the Quaternary (Whitfield et al, 2013;Lewis et al, 2017). The formation and preservation of entrenched, paired terraces across different basins required homogeneous uplift movements.…”

“…Therefore, they hypothesised that incision rates over the Quaternary were controlled by near-uniform bedrock uplift, in the context of climate variability (Stange et al, 2016). According to Lewis et al (2017), the regional elevations of the terrace sequences in the main Pyrenean tributaries of the Ebro River rules out the existence of differential uplift, which is in agreement with the cessation of differential uplift in the Mediterranean shoulder from at least the mid-Pleistocene (Casas-Sainz and De Vicente, 2009;Fernández-Lozano et al, 2011) and with our results derived from the AF index calculations. All in all, Stange et al (2016) hypothesised that incision rates over the Quaternary were controlled by near-uniform regional uplift, as a response to lithospheric thickening in northeastern Iberia with the contribution of the erosional isostatic uplift related to the Ebro basin exorheism (Garcia-Castellanos and Larrasoaña, 2015;Stange et al, 2016;Lewis et al, 2017).…”