![\"\"](\"https:\/\/www.europesays.com\/us\/wp-content\/uploads\/2025\/08\/jim_oconnell.jpg\")
<\/a>James O\u2019Connell<\/p>\nIn collaboration with a colleague from \u00a0Australia\u2019s La Trobe University, James O\u2019Connell<\/a>, Distinguished Professor Emeritus in the Department of Anthropology<\/a>, reported new findings in a study in the journal Archaeology in Oceania. The team highlights conclusions from previous studies that argue Homo sapiens and Neanderthals interbred only once, over a period of several thousand years\u2014between 43,500 and 51,500 before present, or BP. Most modern humans, including Indigenous Australians, carry 1\u20134% Neanderthal DNA<\/a>. The logic follows that modern Aborigine ancestors\u2019 arrival on the continent could not have predated this time range.<\/p>\n Moreover, the dating of most archaeological sites across Australia points to a range between 43,000 and 54,000 years. \u201cThe colonization date falls within that interval,\u201d O\u2019Connell said. \u201cThat puts it in the same time range as the beginning of the displacement of Neanderthal populations in western Eurasia by anatomically modern humans.\u201d<\/p>\n Other hominids, such as Homo erectus, had lived in Southeast Asia for more than a million years, but had not crossed overseas in large enough numbers to create a stable population in Australia. That is an important measure of the significance of Homo sapiens\u2019 arrival.<\/p>\n Dating archaeological sites using OSL<\/p>\n One important Australian outlier among archaeological sites, O\u2019Connell notes, is Madjedbebe, a site dated within a range of 59,000 to 70,000 years ago. The dating technique used in a 2017 study of Madjedbebe published in Nature<\/a> was optically stimulated luminescence<\/a>, or OSL. The technique reads minerals, typically quartz or feldspar, recovered at the site like a \u201cclock\u201d by measuring the energy they store. Radiation accumulates when these minerals are buried, then released when they are exposed to light. Measurements of the amount released determine when the minerals were last exposed to light.<\/p>\n The site has been subject to sand deposition, which may explain the estimated age of the artifacts. \u201cThe question for us has not been about the validity of the date. It\u2019s about the relationship between the date and material evidence of human presence\u2014that is, artifacts. In that part of Australia, many older archaeological sites are in situations where the depositional environment is a sand sheet. Material can move down through those deposits over time.\u201d<\/p>\n Artifacts that are heavier than sand could settle through the sand deposit over time, and as a result, the dating process may have accurately analyzed the age of the sand deposits but not the artifacts they come to contain.<\/p>\n O\u2019Connell also reviewed the hurdles the first Sahul peoples to arrive in Australia would have faced. The Sahul likely relied on rafts or canoes for exploration from Southeast Asia and colonization of Australia. But several challenges existed: first, they would need to engineer marine-capable watercraft that could pass through a \u201cformidable ecological barrier,\u201d the Wallacean archipelago, spanning 1,500 kilometers. Island-hopping through the archipelago, now comprising the nation of Indonesia, to Australia would involve at least eight separate crossings, the longest being 90 kilometers.<\/p>\n Early colonizers arrived in at least four groups<\/p>\n Moreover, these journeys would need to support a sizable population. Citing mitochondrial data, O\u2019Connell noted: \u201cGenomic analysis shows that early human colonizing populations included at least four separate mitochondrial lineages. Simple modeling exercises show that establishing each lineage on Sahul required the presence of at least five\u201310 women of reproductive age, which implies census populations of at least 25\u201350 individuals per lineage among the founders.\u201d<\/p>\n The analysis indicates that these founding populations arrived within a short timeframe, lasting just a few centuries.<\/p>\n \u201cThis strongly suggests that colonizing passage was deliberate, not accidental,\u201d O\u2019Connell said,\u201d and that it required sturdy rafts or canoes capable of holding, say, 10 or more people each plus the food and water needed to sustain those folks on open ocean voyages of up to several days, and of making headway against occasionally contrary ocean currents.\u201d<\/p>\n Altogether, this technological progression adds more weight to a post-50,000-year arrival date, with other innovations and behavioral shifts\u2014including cave art, tools, and ornaments\u2014emerging in that timeframe.<\/p>\n The 50,000-year hypothesis has been a focus of the Australian anthropological debate since 2018. Four separate genetics studies have outlined the DNA ancestries of modern Indigenous New Guineans and Australians, concluding they could not have arrived earlier than 55,000 years ago. The other side of the debate continues to favor a 65,000-year date, which O\u2019Connell disputes.<\/p>\n \u201cI would expect in the next five years or so, the pendulum is going to swing back to general agreement for an under 50,000-year date for Australian colonization. It links up with the broader Eurasian record of an out-of-Africa population wave that spreads across Eurasia\u2014a process that occurs over several thousand years. That raises all kinds of questions about why it happens, what it involves, what prompts it, and what changes in behavior are indicated in greater detail than they are now.\u201d<\/p>\n O\u2019Connell\u2019s co-author and longtime collaborator is archaeologist Jim Allen<\/a>, a retired professor from La Trobe University. Their study, titled \u201cRecent DNA Studies Question a 65 kya Arrival of Humans in Sahul<\/a>,\u201d appeared online June 29 in the journal Archaeology in Oceania.<\/p>\n Header photo: Aboriginal cultural event in Queensland, Australia. Photo credit: Rafael Ben-Ari, via Adobe Stock.<\/p>\n \n MEDIA & PR CONTACTS\n <\/p>\n","protected":false},"excerpt":{"rendered":"Aboriginal Australian culture is regarded as humanity\u2019s oldest continuous living culture. Existing scientific literature estimated their arrival on…\n","protected":false},"author":3,"featured_media":183733,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[26],"tags":[815,159,17304,17302,67,132,17303,68,103236],"class_list":{"0":"post-183732","1":"post","2":"type-post","3":"status-publish","4":"format-standard","5":"has-post-thumbnail","7":"category-genetics","8":"tag-genetics","9":"tag-science","10":"tag-the-u","11":"tag-the-university-of-utah","12":"tag-united-states","13":"tag-unitedstates","14":"tag-uofu","15":"tag-us","16":"tag-when-did-humans-first-colonize-australia-theu"},"share_on_mastodon":{"url":"https:\/\/pubeurope.com\/@us\/115109847700188663","error":""},"_links":{"self":[{"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/posts\/183732","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/comments?post=183732"}],"version-history":[{"count":0,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/posts\/183732\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/media\/183733"}],"wp:attachment":[{"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/media?parent=183732"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/categories?post=183732"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.europesays.com\/us\/wp-json\/wp\/v2\/tags?post=183732"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}<\/a>Burrungkuy (Nourlangie) rock art site in Australia\u2019s Kakadu National Park. Photo credit Chris Olszewski via Wikimedia Commons.<\/p>\n