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This is a response to: Knight, J., 2012. The shape of glacial valleys: comment on Hall (2010). South African Geographical Journal, http://dx.doi.org/10.1080/03736245.2012.663953. This was in turn a comment on: Hall, K., 2010. The shape of glacial valleys and implications for southern African glaciation. South African Geographical Journal, 92, 35–44. [ABSTRACT FROM AUTHOR]

• Great Unconformity investigated using glaciogenic strata. • Whole rock compositions are used as proxy for Ediacaran Upper Continental Crust. • Glacial abrasion created of accommodation space. The "Great Unconformity" across the Proterozoic-Phanerozoic boundary has long been recognised as critical for understandings of the Cambrian Explosion and changes in sediment preservation. However in many parts of the Earth no rock strata are preserved for hundreds of millions of years leading up to the Cambrian Period. This study reports detrital zircon age and whole rock geochemical data from 43 samples of glaciogenic rocks in the Ediacaran Luoquan and Dongpo Formations. Detrital zircon age populations show a distinct peak at ca. 2.5 Ga and minor peaks at 2.2–1.6 Ga, typical of Mesoproterozoic provenance. It has been established that glaciogenic strata are uniquely suited as a proxy for the average upper continental crust (UCC). Applying this principle, the samples presented herein are used to provide insights into the UCC present in the North China Craton (NCC) during the Great Unconformity. This reveals UCC older than the Neoproterozoic but younger than the Great Oxygenation Event. Based upon these findings a tectonic and climatic model is proposed, using a modern analogue from Antarctica, wherein accommodation space was created by glacial abrasion whilst uplift continued throughout the NCC. This overdeepening process provides an explanation for the preservation of these glaciogenic strata, despite the Great Unconformity that surrounds them on all sides and this study contribute towards understanding of processes in the NCC during a critical time when little has survived into the rock record. [ABSTRACT FROM AUTHOR]

A 67-yr-resolution δ18O profile of a230Th-dated stalagmite from Luoshui Cave, central China, is presented to refine the Asian summer monsoon (ASM) history from 336 to 290 kyr BP. The sub-stages of Marine Isotope Stage 9 (MIS 9) are clearly reflected in the Luoshui δ18O record, in line with changes in the Northern Hemisphere summer insolation (NHSI). The concurrency of eight weak monsoon intervals (WMIs) between 320 and 290 kyr BP and shifts in the Atlantic oceanic circulation suggest that monsoon weakening was forced by northern high-latitude climate oscillations with north-south shifts in the Intertropical Convergence Zone (ITCZ). Spectrum analyses show a cyclic change of 1–4 kyr between 320 and 290 kyr BP, similar to the Dansgaard-Oeschger cycles during the last glacial period. This suggests a relatively unstable monsoon state when the northern ice volume reached intermediate levels. The detrended δ18O agrees well with the δ13C record on the millennial to sub-millennial scales, suggesting a coupling of monsoon climate and cave environment. After removal of the summer insolation signal at 65°N, the residual Luoshui δ18O record is highly similar to orbital- and millennial-scale temperature changes in Antarctica in an anti-phased fashion, revealing the significant influence of Southern Hemispheric climates on ASM intensity. The absence of counterparts of the two WMIs between 315 and 310 kyr BP in Antarctica, however, indicates a complicated teleconnection. • A high resolution and precision dating stalagmite record covered MIS9 in China. • A potential chronologic benchmark for global millennial-scale events in MIS9. • Eight WMIs over MIS9 presented anti-phased relationship with Antarctic temperature. [ABSTRACT FROM AUTHOR]