“Climatic fluctuations in the hyperarid core of the Atacama Desert during the past 215 ka”

Abstract

Paleoclimate records from the Atacama Desert are rare and mostly discontinuous, mainly recording runoff from the Precordillera to the east, rather than local precipitation. Until now, paleoclimate records have not been reported from the hyperarid core of the Atacama Desert (<2 mm/yr). Here we report the results from multi-disciplinary investigation of a 6.2 m drill core retrieved from an endorheic basin within the Coastal Cordillera. The record spans the last 215 ka and indicates that the long-term hyperarid climate in the Central Atacama witnessed small but significant changes in precipitation since the penultimate interglacial. Somewhat ‘wetter’ climate with enhanced erosion and transport of material into the investigated basin, commenced during interglacial times (MIS 7, MIS 5), whereas during glacial times (MIS 6, MIS 4–1) sediment transport into the catchment was reduced or even absent. Pelagic diatom assemblages even suggest the existence of ephemeral lakes in the basin. The reconstructed wetter phases are asynchronous with wet phases in the Altiplano but synchronous with increased sea-surface temperatures off the coasts of Chile and Peru, i.e. resembling modern El Niño-like conditions.

Quaternary diversification of a columnar cactus in the driest place on earth

“…However, the stable position of the South American continent for the last 150 Myr (Hartley et al, 2005) in combination with the establishment of the Peru–Chile Current system (PCC) approximately 50 Ma (Cristini et al, 2012) has led to the generally accepted conclusion that the Atacama Desert is an ancient desert, with a hyperarid core since at least the Miocene (Dunai et al, 2005) or even earlier (Hartley et al, 2005). This long‐lasting aridity was, however, repeatedly interrupted by wetter (though still semiarid) phases largely coinciding with globally warmer periods as shown by evidence obtained from 14 C‐dated vegetation fragments from rodent middens (Betancourt, 2000; Latorre et al, 2006), radiocarbon dates of fossil vegetation from the hyperarid core (Nester et al, 2007; Gayo et al, 2012), cosmogenic nuclide exposure dating (Ritter, Binnie, et al, 2018; Ritter, Stuart, et al, 2018), and palaeoclimatic reconstructions based on a drill core (Ritter et al, 2019). Present‐day Atacama vegetation is restricted to the coastal cordillera that benefits from occasional winter precipitation and the influence of coastal fog (Rundel et al, 1991; Schulz et al, 2011) and the Andean foothills, receiving summer rain.…”

Vegetation growth and landscape genetics of Tillandsia lomas at their dry limits in the Atacama Desert show fine‐scale response to environmental parameters

“…Large‐scale genetic differentiation due to migration, colonization, and extinction may mirror the effect of Pleistocene climatic fluctuations, drastically altering extreme aridity, with the recent less arid interglacial phases 75–135 and 175–225 thousand years ago (Marine Isotope Stage 5 and Marine Isotope Stage 7) eventually opening larger corridors for migration in north–south/south–north directions (Ritter et al., 2019). Apart from this information reflecting hundreds of thousands of years, there is also evidence from stratigraphic and stable carbon isotope analysis of subfossil banding patterns inside the dunes that populations from the central and northern genetic cluster represent a vegetation type that has persisted over at least 3,000 years (Jaeschke et al., 2019; Latorre et al., 2011).…”

The origins and implications of paleochannels in hyperarid, tectonically active regions: The northern Atacama Desert, Chile

“…The pervading landscape stability of the region is linked to its extreme hyperaridity, but when that period of stability began and how consistent it has been is contentious, with proponents arguing for the onset of hyperarid conditions as recently as the Pleistocene and as long ago as the Miocene/Oligocene (Alpers and Brimhall, 1988;Amundson et al, 2012;Dunai et al, 2005;Evenstar et al, 2009;Hartley, 2003;Hartley and Chong, 2002;Jordan et al, 2014;Nishiizumi et al, 2005). Several authors have also pointed to evidence that there have been episodic wetter, though still arid, periods within these time-frames, questioning the notion that the landscape is entirely stable over several millions of years (Dunai et al, 2005;Evenstar et al, 2009;Garcia et al 2011;Houston and Hartley, 2003;Oerter et al, 2016;Placzek et al, 2010;Ritter et al, 2019;Sáez et al, 2012), while others note the spatial context and type of proxy used in individual studies may help resolve discrepancies between the various studies (Jordan et al, 2014;Ritter et al, 2018a).…”