Source Count: 14 | Weighted Score: 36 | Source Confidence: [4/5] | Primary Tier: 2 | Last Updated: April 10, 2026
Keywords: Ice Age, maritime, coastal migration, Kelp Highway, Last Glacial Maximum, watercraft, seafaring, Sunda, Sahul, Beringia, Pacific coast, submerged sites, paleolithic
Category Tags: ice-age, maritime-migration, kelp-highway, coastal-route, seafaring, paleolithic, submerged-sites
Cross-References: F_1_22 — Peopling Americas · F_1_29 — Aboriginal Australian First Arrival · F_4_25 — Doggerland Submerged

QUICK SUMMARY

The recognition that maritime capabilities existed during the Ice Age (Late Pleistocene, ~126,000–11,700 years ago) has transformed our understanding of early human dispersals and the colonization of previously isolated landmasses. For much of the 20th century, the dominant paradigm assumed that pre-modern humans were exclusively terrestrial — walking across land bridges, through ice-free corridors, and along river valleys. The sea was viewed as an impassable barrier until the development of "advanced" watercraft in the Neolithic or later. KEY FINDING This paradigm has been overturned by a convergence of evidence from multiple regions: the colonization of Sahul (the Ice Age supercontinent comprising Australia, New Guinea, and Tasmania) at least 65,000 years ago — which required crossing 60–90 km of open water even at lowest sea levels, demonstrating that behaviorally modern humans possessed seagoing capability in the deep Pleistocene; the occupation of islands in the western Pacific (Buka/Bougainville by 28,000 BP, the Bismarck Archipelago by at least 40,000 BP); the colonization of Crete possibly as early as 130,000 years ago (stone tools from Plakias, attributed to pre-sapiens hominins by Thomas Strasser and colleagues, though debated); and the growing evidence for the Pacific Coastal Migration ("Kelp Highway") hypothesis for the peopling of the Americas. The Kelp Highway hypothesis, developed by Jon Erlandson (University of Oregon) and colleagues since 2007, proposes that the first Americans traveled by watercraft along the Pacific coast from Beringia to South America, exploiting the productive kelp forest ecosystems that formed a nearly continuous habitat corridor along the northeast Pacific rim. This model explains the presence of humans at Monte Verde, Chile, by 14,500 cal BP and at White Sands, New Mexico, by possibly 21,000–23,000 cal BP, while the interior ice-free corridor between the Laurentide and Cordilleran ice sheets was still blocked. The principal challenge to maritime archaeology of the Ice Age is that Late Pleistocene coastlines are now submerged under 80–130 meters of water following post-glacial sea-level rise — meaning that the most diagnostic sites of early coastal peoples are inaccessible or destroyed. Advances in submerged landscape archaeology (sonar mapping, ROV surveys, underwater excavation) are beginning to address this gap, with finds at Cosquer Cave (France, underwater Paleolithic art), Haida Gwaii (British Columbia, submerged sites), and off the coasts of Israel and the Channel Islands.

1. VERIFIED CLAIMS (Tier 1 — Peer-Reviewed / Established)

1.1 The Sahul Crossing

• The colonization of Sahul (Australia + New Guinea + Tasmania, connected as a single landmass during glacial lowstands) required open-water crossings of at least 60–90 km across the Wallacea island chain
• The earliest evidence of human occupation in Australia: Madjedbebe rockshelter (Northern Territory, formerly Malakunanja II), dated to approximately 65,000 years ago (Clarkson et al., Nature, 2017)
• This is the oldest unambiguous evidence for maritime capability by any human species — and it occurred during the Late Pleistocene, tens of thousands of years before agriculture or "civilization"

1.2 Island Colonization in the Western Pacific

• Buka Island (Solomon Islands): Occupied by approximately 28,000 BP — requiring a water crossing of approximately 180 km from the nearest landmass
• The Bismarck Archipelago (New Britain, New Ireland): Occupied by approximately 40,000 BP, with evidence of obsidian transport from New Britain to New Ireland across open water
• Okinawa (Ryukyu Islands): The Sakitari Cave site dates to at least 30,000 BP, requiring maritime crossings from mainland Asia or Taiwan

1.3 Sea Levels and Submerged Landscapes

• During the Last Glacial Maximum (~26,500–19,000 BP), global sea levels were approximately 120–130 meters below present
• This exposed vast continental shelf areas (Beringia, Sundaland, Doggerland, vast coastal plains worldwide) and dramatically altered coastline geography
• As ice melted (19,000–6,000 BP), sea levels rose approximately 130 meters, submerging all Pleistocene coastal sites — the most catastrophic loss of archaeological evidence in human history

2. CREDIBLE CLAIMS (Tier 2 — Academic / Debated but Supported)

2.1 The Kelp Highway Hypothesis

• Jon Erlandson et al. (2007): Proposed that the first Americans traveled by watercraft along the Pacific coast, exploiting kelp forests — highly productive marine ecosystems that support rich communities of fish, shellfish, sea mammals, and seabirds
• Kelp forests formed a nearly continuous habitat corridor from northern Japan through the Kuril Islands, Kamchatka, the Aleutians, coastal Alaska, and down the Pacific coast of the Americas to Baja California (and beyond)
• The hypothesis explains: (a) the extreme antiquity of South American sites (Monte Verde at 14,500 BP); (b) the early presence of maritime-adapted peoples on the Channel Islands (California), where Arlington Springs Man dates to approximately 13,000 cal BP; (c) the genetic evidence showing rapid southward movement

2.2 Submerged Site Discoveries

• Cosquer Cave (France): A Paleolithic painted cave whose entrance is now 37 meters below sea level in the calanques near Marseille — containing paintings dated to 27,000–19,000 BP, demonstrating that Paleolithic people used coastal environments that are now submerged
• Haida Gwaii (British Columbia): Underwater archaeological surveys have identified submerged archaeological sites on the continental shelf at depths of 50–150 meters
• Channel Islands (California): Arlington Springs (13,000 BP) and Cardwell Bluffs (12,200 BP) demonstrate early maritime capabilities off the California coast

2.3 Mediterranean Ice Age Seafaring

• Stone tools from Plakias, Crete, described by Thomas Strasser and colleagues (2010, 2011): Acheulean-style handaxes found in geological deposits dated to 130,000+ years ago — if confirmed, this would indicate that pre-sapiens hominins (Neanderthals or Homo heidelbergensis) possessed maritime capability, as Crete has been an island for over 5 million years
• The dating is based on the geological context, not direct dating of the tools — remains controversial
• KEY FINDING If pre-Homo sapiens hominins could cross the Mediterranean, the assumption that maritime capability is a uniquely modern human innovation would be overturned

3. SPECULATIVE CLAIMS (Tier 3 — Possible but Unverified)

3.1 Systematic Ice Age Maritime Networks

• Researchers (e.g., Geoffrey Bailey and the SPLASHCOS program) suggest that Ice Age coastal peoples may have maintained regular maritime exchange networks — analogous to later Mesolithic and Neolithic coastal trade — but the evidence is mostly destroyed by submergence

3.2 The Solutrean Hypothesis's Maritime Component

• The Solutrean hypothesis (Stanford and Bradley) proposes that Ice Age Europeans traveled along the North Atlantic ice edge by boat — while the hypothesis itself is largely rejected, the idea that Ice Age North Atlantic peoples had watercraft is plausible given the Sahul evidence

4. DUBIOUS CLAIMS (Tier 4 — No Credible Source / Contradicted by Evidence)

4.1 "Advanced Civilizations Existed on Now-Submerged Coastlines"

• DEBUNKED While Pleistocene coastal occupation is confirmed, there is no evidence for "advanced" or "lost" civilizations on Ice Age coastlines. The peoples who lived there were hunter-gatherer-fishers, consistent with the archaeological record

Counter-Arguments & Criticisms

The Taphonomic Problem

• The central challenge to Ice Age maritime archaeology is taphonomic destruction: watercraft made of organic materials (wood, hide, plant fibers) do not survive in the archaeological record; and the sites most likely to preserve evidence of maritime peoples are now under 80–130 meters of water
• This creates a systematic bias: the archaeological record over-represents inland, terrestrial adaptations and under-represents coastal, maritime ones

IMAGES

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BIBLIOGRAPHY

1. Erlandson, Jon M., et al | 2007 | "The Kelp Highway Hypothesis: Marine Ecology, the Coastal Migration Theory, and the Peopling of the Americas" | Journal of Island and Coastal Archaeology | ∅ | 2.2::161–174 | ∅ | ∅ | doi:10.1080/15564890701628612 | ∅ | ∅ | ∅
2. Clarkson, Chris, et al | 2017 | "Human Occupation of Northern Australia by 65,000 Years Ago" | Nature | ∅ | 547.7663::306–310 | ∅ | ∅ | doi:10.1080/03122417.2017.1408198 | ∅ | ∅ | ∅
3. Strasser, Thomas F., et al | 2010 | "Stone Age Seafaring in the Mediterranean: Evidence from the Plakias Region for Lower Palaeolithic and Mesolithic Habitation of Crete" | Hesperia | ∅ | 79.2::145–190 | ∅ | ∅ | doi:10.2972/hesp.79.2.145 | ∅ | ∅ | ∅
4. Bailey, Geoffrey; Nicholas Flemming | 2008 | "Archaeology of the Continental Shelf: Marine Resources, Submerged Landscapes and Underwater Archaeology" | Quaternary Science Reviews | ∅ | 24::2153–2165 | 27.23 | ∅ | doi:10.1016/j.quascirev.2008.08.012 | ∅ | ∅ | ∅
5. Dillehay, Tom D., et al | 2008 | "Monte Verde: Seaweed, Food, Medicine, and the Peopling of South America" | Science | ∅ | 320.5877::784–786 | ∅ | ∅ | doi:10.1126/science.1156533 | ∅ | ∅ | ∅
6. Erlandson, Jon M., et al | 2011 | "Paleoindian Seafaring, Maritime Technologies, and Coastal Foraging on California's Channel Islands" | Science | ∅ | 331.6021::1181–1185 | ∅ | ∅ | ∅ | ∅ | ∅ | ∅
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8. Braje, Todd J., et al | 2020 | "Fladmark + 40: What Have We Learned About a Potential Pacific Coast Peopling of the Americas?" | American Antiquity | ∅ | 85.1::1–21 | ∅ | ∅ | ∅ | ∅ | ∅ | ∅
9. Fedje, Daryl W., et al | 2014 | "Early Post-Glacial Migration Through the Ice-Free Corridor and Coastal Environments" | Paleoamerican Odyssey | ∅ | ∅ | In , edited by Kelly E | ∅ | ∅ | ∅ | ∅ | Graf et al., 127 140; College Station: Texas A&M University Press
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11. Flemming, Nicholas | 2004 | "Archaeological Evidence for Vertical Movement on the Continental Shelf During the Palaeolithic, Neolithic, and Bronze Age Periods" | Geological Society Special Publication | ∅ | 175::129–146 | ∅ | ∅ | ∅ | ∅ | ∅ | ∅
12. Wickler, Stephen; Matthew Spriggs | 1988 | "Pleistocene Human Occupation of the Solomon Islands, Melanesia" | Antiquity | ∅ | 62.237::703–706 | ∅ | ∅ | ∅ | ∅ | ∅ | ∅
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14. Clottes, Jean, et al | 2005 | ∅ | Cosquer Redécouvert | ∅ | ∅ | Paris: Seuil | ∅ | ∅ | ∅ | ∅ | ∅

CROSS-REFERENCE INDEX

Generated from V4 expansion plan. Last Updated: April 10, 2026