ABSTRACT Large igneous provinces and associated silicic magmatism can have a significant global climatic effect, so we explored the relationship between the large igneous province record and the ca. 580 Ma Gaskiers glaciation. The late Ediacaran glaciation exists on at least 14 different paleocontinental blocks, and assuming synchroneity, this Gaskiers glaciation was likely of short duration, with estimates ranging from 1.6 m.y. to 340 k.y. The Central Iapetus magmatic province event found in Laurentia, Baltica, and West Africa consists of multiple pulses in the range 620–520 Ma, with the ca. 580 Ma pulse particularly well developed in North Africa. Based on the age matches of 580–570 Ma Central Iapetus magmatic province pulses and the Gaskiers glaciation, and taking into consideration that there is no robust evidence for a major meteorite impact at the time of the Gaskiers onset, we propose that: (1) the initial silicic ca. 580 Ma pulse of the Ouarzazate event (Anti-Atlas of Morocco) helped to trigger the Gaskiers glaciation, and (2) global warming associated with the subsequent ca. 579–570 Ma continental flood basalts, marking the second stage of the Ouarzazate event, helped to end the ice age.

Abstract Lithology is acknowledged to be an important internal catchment control on flow processes to adjacent alluvial fans. However, the role of inherited structural configurations (e.g. bedrock attitude) in catchment connectivity and sediment transport is rarely considered. We examine four young (<100-year-old) active tributary junction alluvial fan systems from the Dadès Valley in the High Atlas of Morocco in terms of their catchment-scale connectivity, sediment transfer and resulting alluvial fan processes. The catchments occur on the same lithologies (limestones and interbedded mudstones), but experience different passive structural configurations (tilted and structurally thickened beds). The fan systems react differently to historical peak discharges (20–172 m 3 s −1 ). Catchments containing tectonically thickened limestone units develop slot canyons, which compartmentalize the catchment by acting as barriers to sediment transfer, encouraging lower sediment to water flows on the fans. Syn-dip catchments boost connectivity and sediment delivery from translational bedrock landslides as a result of steep channel gradients, encouraging higher sediment to water flows. By contrast, translational landslides in strike-oriented drainages disrupt longitudinal connectivity by constricting the valley width, while the gradients of the main channels are supressed by the attitude of the limestone beds, encouraging localized backfilling. This diminishes the sediment to water content of the resulting flows.