Large-scale architecture in non-marine basins: the response to the interplay between accommodation space and sediment supply

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Abstract

Sedimentary successions of non-marine basins can be considered in terms of accommodation space and sedimentary supply changes. Changes in accommodation space controlling the large-scale architecture of non-marine basins are different in areas with high and low sedimentary supplies. Uplift of intrabasinal monoclines and anticlines reduced the available accommodation space, resulting in changes in both the geometry of the depositional sequences and the large-scale architecture of fluvial, mudflat and shallow carbonate lacustrine deposits. Main drainage fluvial systems record areas with a high sedimentary supply, while mudflats and shallow fluctuating lakes represent areas that received less sediment. Two end members in the large-scale architecture of main drainage fluvial system in the Almazán Basin (Spain) are: (i) ribbon-shaped channel fills with low interconnectivity which pass laterally into mudflats dominated by mudstones and evaporites and into palustrine and shallow carbonate lacustrine deposits (mainly in the A2 depositional sequence); and (ii) sheet-like channel fills with high interconnectivity laterally correlated with stacked calcretes in the marginal mudflats (in the upper part of A3). Ribbon-shaped channel fills formed in areas of high accommodation space and sheet-like channel fills formed in areas of reduced accommodation space.

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