Late Holocene fluctuations of Quelccaya Ice Cap, Peru, registered by nearby lake sediments

Abstract

Records of clastic sediment from lakes that receive glacial meltwater provide a means for inferring past glacial fluctuations. However, increased clastic sedimentation has been interpreted to indicate both glacial advance and recession. Here we examine the timing of clastic sediment deposition in Challpacocha, a glacially fed lake located downvalley from Quelccaya Ice Cap (QIC), Peru, in comparison with known ice cap margin fluctuations. Using a comparison with a nearby non-glacial lake, Yanacocha, we document that a record of clastic sediment flux from Challpacocha reflects meltwater-derived sediment. We then compare the clastic sediment record from Challpacocha with the Qori Kalis glacier moraine record. We find that organic-rich sediment was deposited primarily during the late Holocene advance of QIC (before $CE 1490). In contrast, clastic sediment was deposited during QIC recession ($CE 1490($CE -1970. Peaks in clastic sediment flux are associated with the onset of ice retreat. We suggest that this pattern of clastic sediment deposition reflects changing meltwater production and/ or glacial erosion during ice advance and retreat and supports models of increased clastic sedimentation during ice retreat.

Equilibrium line altitudes along the Andes during the Last millennium: Paleoclimatic implications

“…Based on these data, we suggest that the Tributary I moraines mark the LMM ice extent at the Vilcanota site and that this occurred at <560 yr BP. Similar dates constrain the LMM at Quelccaya Ice Cap, confirming our findings (see section ‘Discussion’; Stroup et al, 2014, 2015).…”

“…On the northwest side of Cordillera Vilcanota, in the Upismayo valley, Mark et al (2002) showed that the innermost moraine complex of the area was deposited after 340-560 cal yr BP (328 ± 46 14 C yr BP). In addition, at Quelccaya Ice Cap (15 km to the southwest of Vilcanota site), Stroup et al (2014Stroup et al ( , 2015 showed that the LMM in the Qori Kalis and Chalpacocha valley occurred at >520 ± 60 yr BP. Similar results were obtained by Phillips et al (2016), who constrained the LMM in the adjacent Huancané valley between 670 and 410 yr BP.…”

Unique Collections of 14C‐Dated Vegetation Reveal Mid‐Holocene Fluctuations of the Quelccaya Ice Cap, Peru

“…They are not intended for use as accurate exposure ages, but instead are used to examine the age differences between adjacent and nearby surfaces. However, the CH‐2‐Unit‐2 record contains clastic rich (∼95%) sediment, which suggests higher meltwater production and an increase in subglacial erosion, corresponding to the beryllium‐indicated QIC retreat from 1490 to 1710 CE (Stroup et al., 2015). The monitoring of Qori Kalis has been discussed in several studies (Brecher & Thompson, 1993; Hanshaw & Bookhagen, 2014; Kelly et al., 2015; Lamantia, 2018; Stroup et al., 2014; Thompson et al., 2006).…”

“…Numerous studies of the QIC detail a variety of methods that have been utilized to investigate the ice cap's past extent. These include radiocarbon dating of organic material found in sediment (Kelly et al., 2012), radiocarbon dating of vegetation remains (Buffen et al., 2009), cosmogenic nuclide surface exposure age dating ( 10 Be) (Kelly et al., 2015; Stroup et al., 2014, 2015), lake sediment records (Rodbell et al., 2008; Stroup et al., 2015), and paleo‐glacier reconstruction from moraine mapping (Mark et al., 2002; Mercer & Palacios, 1977). While many studies provide regional paleoclimate records from ice cores, moraines, and lake sediments (Rodbell et al., 2008; Stroup et al., 2015; Thompson, 2000), there are few precisely dated glacial landforms in the tropics (Kelly et al., 2015) which limits the understanding of glacier and ice cap behavior in response to changes in climate.…”

The Medieval Climate Anomaly in South America

“…Elevated amounts of organic matter were found in the MCA section of two lakes in the southern Peruvian Cordillera Central, Tarn Challpacocha (site 25) and Tarn Yanacocha (site 28) indicating MCA warming (Stroup et al, 2015) (Fig. S8).…”