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Articles by John Hellstrom
Onset of summer aridification and the decline of Homo floresiensis at Liang Bua 61,000 years ago - Communications Earth & Environment
Abstract The cause of the disappearance of the primitive hominin Homo floresiensis from the Indonesian island of Flores about 50,000 years ago is a key question in palaeoanthropology. While the potential roles of climate change and human agency continue to be debated, the history of freshwater availability essential for survival at the type locality, Liang Bua, remains poorly understood.
Warming drives dissolved organic carbon export from pristine alpine soils - Nature Communications
Abstract Despite decades of research, the influence of climate on the export of dissolved organic carbon (DOC) from soil remains poorly constrained, adding uncertainty to global carbon models. The limited temporal range of contemporary monitoring data, ongoing climate reorganisation and confounding anthropogenic activities muddy the waters further.
Elevated Southern Hemisphere moisture availability during glacial periods - Nature
Abstract Late Pleistocene ice-age climates are routinely characterized as having imposed moisture stress on low- to mid-latitude ecosystems1,2,3,4,5. This idea is largely based on fossil pollen evidence for widespread, low-biomass glacial vegetation, interpreted as indicating climatic dryness6. However, woody plant growth is inhibited under low atmospheric CO2 (refs.
Full article: Pleistocene raptors from cave deposits of South Australia, with a description of a new species of Dynatoaetus (Accipitridae: Aves): morphology, systematics and palaeoecological implications
Abstract The Pleistocene fossil record of Australian raptors (Accipitridae: eagles, hawks and Old World vultures) is very poorly understood with only three distinct extinct species confirmed until now. The small Necrastur alacer remains unstudied; however recent research has established Cryptogyps lacertosus as a valid species that, along with the very large Dynatoaetus gaffae, has potential affinities with the Aegypiinae–Circaetinae clade.
Reply to: Clusters of flowstone ages are not supported by statistical evidence
replying to P. Hopley et al. Nature https://doi.org/10.1038/s41586-021-03586-0 (2021) Access options Subscribe to Journal Get full journal access for 1 year $199.00 only $3.90 per issue All prices are NET prices. VAT will be added later in the checkout. Tax calculation will be finalised during checkout. Rent or Buy article Get time limited or full article access on ReadCube. from$8.99 All prices are NET prices.
The rapid climate changes of the last glacial period
By Ellen Corrick, Russell Drysdale and John Hellstrom Tuesday September 1, 2020 Disko Bay glacier during midnight sun season of polar summer. Ilulissat, Greenland. Adobe Abrupt changes in climate have occurred throughout Earth’s geological past. Some of the largest and most rapid changes occurred during the last glacial period, which extended from 115,000 to 11,700 years ago. At that time, the global climate was considerably cooler and drier than today.
The rapid climate changes of the last glacial period
Abrupt changes in climate have occurred throughout Earth’s geological past. Some of the largest and most rapid changes occurred during the last glacial period, which extended from 115,000 to 11,700 years ago. At that time, the global climate was considerably cooler and drier than today. Expansive ice-sheets covered northern Eurasia, and about half of North America. Global sea-levels were around 130 metres lower than at present.
We pieced together the most precise records of major climate events from thousands of years ago. Here’s what we found
Between 115,000 and 11,700 years ago, the Earth would have been almost unrecognisable. Massive ice-sheets covered northern Europe and northern Asia, and about half of North America, and global sea-levels were as much as 130 meters lower than today. In this period, known as the “last glacial period”, the climate was much cooler and drier than today. It was punctuated by some of the largest and most rapid climate change events in Earth’s recent geological history.
Synchronous timing of abrupt climate changes during the last glacial period
Research Article View ORCID ProfileEllen C. Corrick1,2,*, View ORCID ProfileRussell N. Drysdale1,2, View ORCID ProfileJohn C. Hellstrom3, View ORCID ProfileEmilie Capron4,5, View ORCID ProfileSune Olander Rasmussen5, View ORCID ProfileXu Zhang6,7,8, View ORCID ProfileDominik Fleitmann9, View ORCID ProfileIsabelle Couchoud2,1, View ORCID ProfileEric Wolff10 1School of Geography, The University of Melbourne, Melbourne, Victoria, Australia.
Using speleothems to constrain late Cenozoic uplift rates in karst terranes
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U-Pb-dated flowstones restrict South African early hominin record to dry climate phases
1. Wood, B. & Boyle, E. K. Hominin taxic diversity: fact or fantasy? Am. J. Phys. Anthropol. 159, 37–78 (2016). 2. Herries, A. I. R. & Shaw, J. Palaeomagnetic analysis of the Sterkfontein palaeocave deposits: implications for the age of the hominin fossils and stone tool industries. J. Hum. Evol. 60, 523–539 (2011). 3. Granger, D. E. et al. New cosmogenic burial ages for Sterkfontein Member 2 Australopithecus and Member 5 Oldowan. Nature 522, 85–88 (2015). 4. Kramers, J. D. & Dirks, P. H. G. M.
The influence of Antarctic subglacial volcanism on the global iron cycle during the Last Glacial Maximum
Samples of brown-reddish subglacial calcite crusts were collected from the bedrock, consisting of glacially polished amphibolite, where these were not covered by snow, within a total area of 100?m2 (location shown in Fig. 1b) in the course of a survey targeted to obtain terrestrial cosmogenic nuclide exposure ages on adjacent moraines. The morphology of the crust was typical of similar deposits occurring on exposed carbonate and non-carbonate bedrocks of Alpine glaciers.
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