Siberian Archaeology 2: Diring Yuriakh

The Diring Yuriakh site lies approximately 140km SSW of Yakutsk on the Lena River, on a point formed by its junction with its tributary, the Diring Yuriakh creek.

 

 

Diring Yuriakh location. Photo credit: Walters 1997 (1).

Original caption: Fig. 1. Map of eastern Russia showing the location of Diring Yuriakh.

 

Approaching the Diring Yuriakh site along the Lena River (3).

Photo credit: Courtesy of the Center for the Study of the First Americans.

The Diring Yuriakh site was discovered accidentally, in June 1982, by Russian geologists, led by O. V. Grinenko whilst they were excavating a geological test pit to show the Cenezoic deposits of the 90m Tustakhsk terrace of the Lena River to participants in the International Union for Quaternary Research, (INQUA) congress XI held in Moscow and came across human bones (2).

The human bones recovered were of late Neolithic date and proved to be from a series of burials or graveyard belonging to the Ymyiakhtakh culture as shown by an excavation carried out in October of the same year, by Yuri Mochanov.

 

Excavations at Diring, adapted from Mochanov 1993 (2)

Yuri Mochanov

Photo credit: Courtesy of the Center for the Study of the First Americans (3).

The history of the site discovery and subsequent excavations is recounted by Mochanov in his first English language publication on the site The Ancient Palaeolithic Site of Diring and the Problem of a Nontropical Origin for Humankind (2). Most of what follows is a summary of that paper:

 

“Near burial V at a depth of 60cm, a flint core, seven flint microblades and 14 small flint flakes were found in the second paleosol from the bottom.. and belong to the late Neolithic Diuktai culture.. in the lower paleosol a concentration of quartzite artifacts was found lying directly on top of the gravels. These included an anvil cobble, two cobble hammerstones, eight amorphous flakes and 92 pieces of debitage.. The concentration of quartzite artifacts was separated from the Diuktai finds by a layer of sterile sand 5-12cm thick. The absence of any kind of diagnostic tool prevented the clear establishment of a cultural-chronological relationship for the quartzite artifacts. In appearance they were unusual for the early cultures of the Yakutia (the region of the site). ..the flakes were obtained (from cores) by a nonsystematic method of splitting cobbles ..unlike the Diuktai flint artifacts, there were well-preserved traces aeolian abrasion on many of the quartzite artifacts ..Traces of abrasion were present not only on pebble cortex, but on the cleavage plane of the detached flakes and debitage as well. ..I have not in 20 years of work on archaeological sites of Northeast Asia, encountered either the technique of nonsystematic flaking of cobbles or wind-abraded stone artifacts. ..(previous) experiments in the flaking of cobbles and nodules of various stone and examination of various museum collections of stone tools permitted the following conclusion: the method of nonsystematic flaking (of cobbles and nodules) was characteristic only during the earliest stage of the Stone Age, when people had not yet mastered the techniques of removing flakes from specially prepared cores..”

 

Flaked Cobbles and Chopper (3).

Photo credits: Courtesy of the Center for the Study of the First Americans.

 

 

 

Core with flakes (above) and flakes refitted (below). (3).

Photo credit: Courtesy of the Center for the Study of the First Americans

In a roundabout manner Mochanov then brings up the technologically similar, simple nonsystematic breaking of stones found in the Oldowan and Acheulian lithic complexes of approximately 2.5 to 1.5Mya from Africa.

 

However he goes on to caution that the site investigation at that stage was far, far from complete and would need a huge amount of systematic work, particularly of stratigraphy to draw any firm conclusions.

 

In 1983, Mochanov was back excavating again. He continues his description of the excavations, noting that by the end of this season 1300 quartzite artifacts of the same type found in the previous year had been found and that the site had expanded to cover 3000m². Some further commentary follows, reinforcing his belief that the site’s lithic assemblage resembled the Oldowan industry of Africa. He notes the discrepancy between the PAE (Prelinsk Archaeological Expedition) view of the site stratigraphy, that aeolian deposits overlay the cultural stratum and his assumptions of great age (dependent on then layers above the cultural bearing stratum 5 being of alluvial origin)  and decides more work needs doing on the site stratigraphy. Here is his description of that stratigraphy from 1983:

 

“In 1983 it was determined that the excavations, trenches, and test pits that the wind abraded quartzite artifacts on the 105-120m terrace were derived from the gravel-pebble-cobble deflated layer which was lying on the red-coloured fluvial sands..

(Deflation is defined as “The removal of surficial deposits of soil, sand or fine gravel by wind action.”) On a bedrock foundation of Cambrian limestone at an elevation of 105m +/- 2m.. It was observed that the culture-bearing stratum intersects the polygonal, sand filled ice-wedges, extends into the fluvial sands at 109-120m, and also intersects the lower gravels at 105-109m and in some places the eluvial top of the bedrock terrace.

In several places on the 105-120m terrace, chiefly at elevations greater than 108m, horizontally layered sandy deposits with cryogenic syngenetic textures and structures were recorded above the culture-bearing stratum and were assigned by us to the floodplain facies of the alluvium. Its thickness varied from 1 to 3.5m. The alluvial, owing to postdepositional denudation in some areas, mostly at the outer bench of the terrace, were marginally preserved or had lost their texture and structure, but in other areas they occurred as distinct ridges separated by furrows... The leaders of the A-14 (geological expedition mention above) had taken it (the sandy layers above the culture bearing stratum) for a dune and evidently therefore decided that its deposition was due to aeoliain processes. They adhered to this point of view until 1985. However in 1983 the PAE (Prelinsk Archaeological Expedition) had clearly noted that at the basal edge of the 105-120m terrace, the horizontally layered sands which covered the culture-bearing stratum were deposited as a sheet wash over the loamy-clay deposits of the 125-135m terrace, and for this reason they could not be aeolian.”

 

This is a key point in Mochanov’s argument. If the deposits above the cultural-bearing stratum are alluvial and not aeolian in origin, then the stratigraphy is intact and therefore the artifacts are EXTREMELY old as he has assumed all along. Mochanov concludes:

“Based on the geomorphological development of the middle Lena terrace, the 105-120m terrace was determined to be Cherendeisk or older, ..which contain the culture-bearing stratum - was restricted to the range of 2.4-1.5 million years.”

 

Here is a schematic view of the stratigraphy from Mochanov’s paper (2):

Mochanov’s schematic of the stratigraphy adapted from his 1993 (2) paper, note I have added a red line to indicate the cultural bearing layer, just above the v-shapes of the ice wedges. Original caption reads: Fig. 2. A. Schematic section of the Tabaginsk terrace in the vicinity of the Diring site. (a) Kembriisk (Cambrian) limestone; (b) gravel stratum2; (c) sand of stratum 3; (d) sandy Ice Wedges; (e) deflated culture bearing gravels; (f) sands, sandy loams and loams of strata 6-10; (g) sandy loams and loams of stratum 11; (h) sandy loams and loams of stratum 13; (i) sands of strata 12 and 14-18; (j) cultural remains of the Most Ancient Paleolithic; (k) drill cores; (l) numbers of the strata. B. (inset) Schematic profile of the locale showing the bedrock foundation of the terraces in the vicinity of the Diring site (not to scale).

 

In 1984 Mochanov was able to acquire more resources, in the form of a bulldozer, to test the extent of the cultural layers extending away from the river and under the higher terrace levels. During that season (2) and subsequently (4) 15850m² of sod was removed, and an area of excavations of 10220m² was excavated, of which 7743m² was the cultural bearing layer. In total 40m of overburden was removed from the centre of the site. By 1988 28 lithic clusters numbering thousands of artifacts had been recovered (4).

 

 

Diring Yuriakh upper site with overburden removed. Note the extreme depth of sediments removed at left of photograph.

Photo credit: Courtesy of the Center for the Study of the First Americans (3).

During the next part of the paper, Mochanov then theorises at length about the whole geological chronology of the Diring Yuriakh-Lena River watershed. Whilst interesting it has no bearing on the overall dating of the stratum 5, the cultural-bearing stratum.

He then to rebuts the views of Medvedev that “for wind abrasion (of the type seen at Diring Yuriakh) of stone to occur, severe artic desert conditions with continuous high velocity - more than 70m/s - were necessary” by detailing the palynological evidence that, pine, larch, fir, birch, bird cherry, alder and mountain ash grew in the region at the time and thus preclude the area being an artic desert. He further discounts this scenario by fairly pointing out that, if winds of this ferocity has scoured the site, the tiny pieces of flake debitage would now not remain in situ as they were indeed found.

 

He then attempts to justify ignoring the opinions of geologists Alexeev and Kamaletdinov that the stratigraphy has ..“inconvenient geological layers related to lake, slope and aeolian deposits” and their judgement that the maximum age down to the bedrock to be no more than a million years.

 

In summary Mochanov sees the entire deposition sequence above the bedrock, as being attributable to the fluvial/interfluvial cycle of the Lena River. Furthermore he sees the cultural-bearing layer as being formed, eroded, the artifacts being abraded by windblown sand, then re-buried by further fluvial/interfluvial cycles of the Lena River. Thus the dates of this layer MUST, according to his theory, be between 2.5 and 1.5 Mya. He notably chooses to ignore the opinions of the geologists that the lithic artifact-baring stratum has been buried by a layer of sediments which are of aeolian origin.

 

Of more interest is the single suspiciously (human?) fractured mammal bone of ungulate or proboscid origin. It was found in a concentration of lithic artifacts and is of obvious antiquity being entirely mineralised.

 

The lithics themselves are quite remarkable in their crudity and their obvious human manufacture.

 

Mochanov gives the following circumstances as indicating their human provenance:

·         The lithics are found in concentrations.

·         Lithics not randomly scattered across the landscape

·         Lithics found at maximum distances of 0.5Km from each other

·         Reconstruction of cores was possible using flake debitage

 

Characterising the concentrations of lithics, Mochanov notes that vast majority were of quartzite with a very low number of sandstone-quartzite artifacts also present. The concentrations of a few hundred artifacts occupied areas of about 100m². A typical assemblage of artifacts as for example from concentration 14 consisted of 18 kinds of ordinary choppers, multiedged macrochoppers one sharpened end microchopper (including one with a bill), one lateral microchopper, an example of the uniquely Siberian Skreblo -  a wide oval scraper, variously poorly formed tools, possibly resembling scrapers, knives, points or burins. Lastly a number of hammerstones and anvils. There was also considerable flake debitage, all the above grouped round a heavy cobble-anvil of dimensions 42 x 31 x 30cm.

Anvil on lag-surface

Photo credit: Courtesy of the Center for the Study of the First Americans (3).

Mochanov then freely admits just how basic and depauparate the assemblage is: “The basic distinction of the Diring Complex from the earliest African complex is the fact that at Diring multifaceted spheroids, bifacial discs, clearly expressed chopping tools, proto-axes, well-retouched small tools on chunks and flakes and above all, unmistakeable cores are lacking.”

Of final note in this paper is the claim that work by A. V. Pen’kov established a range of dates based on the paleomagnetic reversals above and below stratum 5 (the cultural-bearing layer). These ranged between “4.2-3.9 My (stratum 3), 3.15-3.0My (stratum 6, 7 and 8). A variation is possible as well 3.4-2.9 or 2.5 My. At present a “minimum” variation also cannot be excluded: 19.-1.7 My.”

 

 

What on Earth are we to make of all this? Oldowan type stone tools at an impossibly early date way out there in Siberia of all places? And the lead investigator at odds with his colleagues (I have only hinted at that - the detailed story shows far greater depths of disagreement)?

And yet.. and yet those tools are so obviously formed for human purposes.. the only real question is can we get REAL dates and then perhaps decide on the really juicy bit.. The WHO.. the which species of human!

 

 

Luckily for us someone did step up to try to bring some cold hard science to the site.. and luckily for us it was a well-respected outsider.. none other than Michael Waters of Buttermilk Creek fame (see here).

Here is how Waters (1) explains the stratigraphy of the site:

“At Diring, unconsolidated Quaternary sediments rest unconformably on Cambrian-age limestone. These Quaternary sediments are divided into four major stratigraphic units labeled I through IV (from oldest to youngest) and are further subdivided on the basis of lithostratigraphic criteria (Fig. 2). These sediments are of alluvial and eolian origin. The oldest unit that overlies limestone bedrock is composed of well-rounded gravel (unit Ia). Most of the gravels are pebble-sized and composed of quartzite. The gravels are conformably overlain by sands (unit Ib). The sand ranges from coarse-to-fine, angular-to-subangular grains that occur in horizontal beds and crossbeds. A few thin beds of well-rounded fine gravel and granules are interbedded in the sand. Unit I represents fluvial deposition in a sandy braided channel of an ancestral Lena River.

The gravel and sand (units Ia and Ib) are cut by two sets of wedges (3, 5) filled with sand (unit II). Wedges in the first set are large, ranging from 0.6 to 5 m wide and 4 m deep. Wedges in the second set are less than 0.5 m wide and reach a maximum depth of 1.1 m. All the wedges are filled with well-sorted, subangular medium sand. In some cases, small gravels (0.5 to 1 cm in diameter) form distinct vertical beds in the sand wedge fill. Large pebbles or cobbles are absent from both wedge sets. The sand from unit II is well sorted and the grains show evidence of wind abrasion; thus, the sand appears to be of eolian origin. The larger wedges appear to have been truncated by later deflation, whereas the smaller wedges extend downward from the deflation surface. Resting on top of the eroded surface of unit Ib and the truncated sand wedges (unit II) is a gravel lag. This is a loose lag with mostly small pebbles (92%), a few large pebbles (7%), and rare boulders (1%). Compositionally, most of the gravels are siliceous (70%), with the remainder composed of quartzite (20%) and vein quartz (10%). Most of the larger pebbles, and all cobbles and boulders, are quartzite. These quartzite clasts are generally well rounded.

All gravels are wind-abraded, showing pits, facets, and polish. This lag appears to have been created by the eolian deflation of unit I. The upper part of unit I must have contained lenses of gravel and large boulders that were deflated to a common surface and concentrated into a loose lag as the fine-grained sediments were removed when the wind swept over the area. The artifacts from Diring are found on this deflation lag.”

So an extremely simple stratigraphy then: the cultural-bearing stratum in an aeolian deflation lag and NOT of alluvial origin as Mochanov had assumed. In fact it was exactly what his own geologists had told him it was in 1983!

Walters 1997 Fig 2.(1) Original caption: Generalized cross section of the stratigraphy at Diring Yuriakh and associated TL ages. Solid triangles indicate the positions of the artifacts.

As can be seen from the diagram Thermoluminescence (TL) dating was used to date the sediments. Here is how Walters explains the method and his results:

“Thermoluminescence (TL) dating of sediments was the only acceptable technique available to assess the age of the stratigraphy and artifact horizon at Diring because of the proposed antiquity of the site and the absence of materials suitable for other dating methods. Loess and cover sands at Diring Yuriakh are suitable for TL dating because these sediments presumably received prolonged light exposure during subaerial eolian transport and deposition.

This process resets the TL signal to a low definable level. As a test, we exposed the sediment from Diring to sunlight for 16 hours. As a result, natural TL emissions were substantially reduced by .84%. A slightly greater reduction in TL occurred after 8 hours of exposure to an ultraviolet (UV) light–dominated source, which approximates sunlight exposure for .24 hours and provides a better estimate of the full solar resetting level. The 8-hour UV exposure values were used to calculate the TL ages reported here because they provide a maximum estimate of the predepositional TL level and a finite estimate on eolian deposition. The fine-grained (4 to 11 mm) feldspar-dominated fraction was used for dating because of the greater likelihood of solar resetting of the grains and because the grains are ubiquitous in the stratigraphic sequence. The paleodose was determined by the total-bleach technique; there was no discernable instability in the laboratory- induced emission. An attribute of the sediments from Diring that contributes to rendering TL ages >100 ka is the uniform and relatively low dose rate for loess and eolian sand units at 3.7 to 4.0 grays (Gy)/ka and 3.6 to 2.8 Gy/ka, respectively. We obtained nine TL ages at Diring. Fine-grained polymineralic samples from units IIIa and II (large truncated wedge) that bound the artifact-bearing horizon responded sufficiently to laboratory addititive dose and yielded ages of 267 +/- 24 ka (sample OTL471) and 366 +/- 32 ka (OTL472), respectively. .. The similarity among TL ages on polymineral samples and quartz grains, despite different levels of luminescence emissions, indicates that TL ages reflect burial time and are not an artifact produced by combining TL signals of various apparent ages. .. TL ages from the loess of unit IIIe that overlies the archaeological material at Diring provides a minimum age estimate for the artifact-bearing surface of about 260 ka, whereas the TL age from unit II underlying the artifact surface provides a maximum age of about 370 ka. The artifact surface, then, may date to about 300 ka.”

 

Whilst there has been some criticism of Walters’ TL methodology over the years, generally the sites’ antiquity is now well established.

 

Verdict:

 

Site inhabited ca. 300, 000 years ago.

 

Likely candidates Homo erectus or Homo heidelbergensis

 

 

References

1. Michael R. Waters, Steven L. Forman and James M. Pierson. 1997. Diring Yuriakh: A Lower Paleolithic Site in Central Siberia. Science Vol. 275 pp. 1281-1284. DOI: 10.1126/science.275.5304.1281

2. Mochanov, Y. A. 1993. The Ancient Palaeolithic Site of Diring and the Problem of a Nontropical Origin for Humankind. Arctic Anthropology vol. 30, no 1 pp22-53.

 3. Center for the Study of the First Americans. Retrieved from: http://csfa.tamu.edu/gallery.php

4. Carlson, R.L. 2001. Diring Yuriakh: An Early Paleolithic Site on the Lena River, Eastern Siberia. Indo-Pacific Prehistory Bulletin 21, (Melaka Paers vol. 5)







The Peopling of the Americas I: Beringian Land bridges, Formation and Paleoecology

The peopling of the Americas has caused spirited and sometimes heated academic debate among scientists in the USA for decades.

For centuries the route of entry has generally been accepted as across the Bering Land Bridge.

The first writer to suggest this possible route of the entry of people into the American continent was a Jesuit monk named Jose de Acosta. De Acosta had arrived on the Caribbean coast of South America at Carthagena and travelled onwards to the settlement of Nombre de Dios. From here he journeyed through 18 leagues of tropical forest via the route pioneered by Balboa and De Avila to Panama. Once on the Pacific he took ship once more and reached Lima in the recently conquered Peru. It was while travelling to his new posting that he began recording his experiences and observations of fauna, flora, peoples and geography of the Americas. As an educated European he had read the extant writings of the ancient philosophers and upon crossing the equator he later related “He expected, as professed by the philosophers that he had studied, an unbearable intense heat in crossing the equator, but found it to be so cool in March, that he laughed at Aristotle and his philosophy”¹

De Acosta spent many years in Peru carrying out missionary work and lecturing on theology. Initially assisting the Viceroy, Don Francisco de Toledo he travelled the country for two years gaining a grounding in geography of the country. Subsequently he lived at Juli, on the shores of Lake Titicaca the main seat of the Jesuit order in Peru. His missionary duties required him to travel widely and thus he became intimately acquainted with the native peoples and their customs.

One theological problem that was therefore at the forefront of de Acosta's mind was a basic one: scriptures clearly defined man's origins as being in the Old World, therefore theologians must account for a branch of humanity in the New World. De Acosta phrases it thus:

 “Scripture teaches us that all men are descended from a first man. Hence man must have come to the Indies (The Americas) from Europe, Asia or Africa, but such pronouncements do not tell us the manner of travel or the route. ..How could the human race have traversed so great an immensity of seas and lands? How could so large a number of people have been concealed for so many centuries?”

De Acosta goes on to logically rule out intended voyages using navigation techniques as no evidence of such abilities used by ancient peoples exists in the written or oral traditions of the three continents known up to the discovery of the Americas. He discounts accidental voyages as the great diversity of animal life in the New World also had to arrive there in some manner, and in the case of terrestrial animals this had to be via a land connection with some continent.

He therefore goes on to conclude that the Indians and likewise the animals found in the New World probably arrived via some point in the far north at which the two worlds are either connected or closely approximate. He speculated that the Old and New Worlds in the far north either, “continued and joined with the other” or “they approach on nearer unto another”¹ such that the gap would not greatly hinder migration of animals or man.

In 1587, after 16 years in the Peru and later, Mexico de Acosta returned to Spain and occupied various prestigious offices, including lastly rector of the college at Salamanca. He published three great works based on the extensive manuscripts he had compiled during his time abroad. These were: De Natura Novi Orbis, De promulgatione Evangelii apud Barbaros, sive De Procuranda Indorum salute and above all, the Historia natural y moral de las Indias which contains his theory of the man’s entry into the New World.

Photo credit: Google Digital Commons
















The influence of these works was so profound that de Acosta became known as “the Pliny of the Americas”. Thus the land route for the peopling of the Americas entered the intellectual cannon almost from the beginnings of written history of science.
 
This close approach of one land mass to the other was first discovered by Semyon Dezhnyov in 1648 but news of the confirmed close proximity of the Asian and American continents only reached Europe 80 years later when Danish-born Russian navigator Vitus Bering entered the strait, now named after him, in 1728.
 
The theory remained in the realms of theological speculation until late in the 19^th century, when Wallace² suggested that the shallow seas separating Siberia and Alaska, specifically the area around the Bering Strait seemed the most likely site of geologically recent Eurasian-American land connections. In 1898 Wallace³, based on  water depth soundings of Bering Sea, Chukchi Sea and Being Strait, wrote that, “in later geologic times, more than once and perhaps during prolonged periods [there existed] a wide terrestrial plain connecting North America and Asia” .
The timing of the Bering Land Bridge formation remained a thorny issue for scientists with best estimates based on the synchronicity of Asian and North American, fossil, mammal faunas as detailed in the works of Osborn⁴ Willis⁵ and Simpson⁶.
The mechanism of Bering Land Bridge formation was initially thought to be related to tectonic events, however in 1934 Daly⁷ brought forward the theory that sea levels fluctuated drastically during the Ice Ages in response to the amount of water stored on land as continental glaciers such as the Laurentide of North America. Finally the area of the land connection was given its name; Beringia or the Bering Land Bridge by Hulten⁸ in 1937. His work noted that while large areas of North America and Southern Siberia were glaciated, large areas to the north of these remained ice-free refugia for many boreal plant species and animals and that the two continents were connected by the Bering land Bridge for a considerably length of time.
Thus the timing and existence of the Bering Land Bridge while firmly based in the, then current scientific evidence, required unequivocal data to fully prove the theory. With the intervention of World War Two the uncovering of definitive, confirmatory evidence had to await the emergence of a new generation of scientists working in the region.
 
One such scientist was David Moody Hopkins. After graduating from the University of New Hampshire in the summer of 1942 with a degree in Geology, he enrolled as a doctoral student at Harvard. Only three weeks into term-time he was offered a job with the U.S. Geological survey in Alaska locating strategic minerals for the war effort. His advisors at Harvard recommended that he take the post and finish his studies later, after al,l at 20 years of age Hopkins was of prime draft age. He thus accepted the job and was at once posted to Alaska. Through the autumn of 1942 and the summer of 1943 Hopkins mapped the distribution of molybdenum and coal deposits but also found time to collect Pleistocene fossils or marvel at, and study the glaciers and mountain scenery around his camps at Muir Inlet and in the Matanuska mountains. Each autumn it was back to Washington D.C. to write up his reports. In late 1944 he chose to write up his reports in Anchorage, Alaska hoping to drafted in Alaska and not back east. Thus it was that he was drafted whilst still in Alaska and did his basic training there. On completion of the course intelligence and aptitude tests were carried on the recruits, by the army to see which assignments they were best suited for. Experience was also a factor. Hopkins thus gave his experience working for the USGS, fictionalised teenage work on the railroad in New Hampshire and lastly experience of meteorological observations based on a class on climatology he had taken at UNH and watching a friend take such measurements. Basically it was an ‘Anything but the Infantry’ strategy. The army took one look at Hopkins’ weatherman experience and posted him 600 miles north to the extremely stormy cold bay, at the base of the Aluetian chain. Here Hopkins spent the rest of the war carrying out meteorological observations and using Hulten’s Flora of the Aluetian Islands to identify and collect plants. He was finally discharged in the spring of 1946 in the wake of the eruption of Okmuk Caldera on Umak Island.
Consequently, he returned safe and sound to Harvard to complete his Ph. D. He studied under Kirk Bryan an early proponent of the multidisciplinary approach to Geology. This approach was certainly absorbed by Hopkins. It was this combined with his experiences in Alaska before and during the war that formed Hopkins approach to Geology, in that he was prepared to take evidence from a wide field of knowledge and synthesise it into new explanations of natural phenomena. It was then that Hopkins began to see himself as more of a paleonaturalist blending the geology of landscape formation and his naturalist interests of early youth. This combination of interests, led him to be one of the first doctoral students to achieve a Ph. D from Harvard in Quarternary Geology.
 
Going back to work for the USGS Hopkins was able to pursue his interest in the Quartenary Geology of Alaska and in particular the history of the cyclic formation and inundation of the Bering land Bridge. By 1948 he was back in the field, in Alaska with a hand-picked team focussing on the subject that would become his life’s work.

Hopkins at Hammum Creek near the Imuruk River 1948.
Photo Credit O’Neill¹⁰

Sigafoos, Quay and Hopkins drying their gear at Lava Lake camp 1948
Photo Credit O’Neill¹⁰

Through the late 1940’s and 1950’s Hopkins never missed a season in Alaska, despite the tragically early death of his first wife, a disastrous second marriage and being wed again for a third time! He often based himself around the Seward peninsula and worked with a range of scientist or visited others working in the region such as Louis Giddings and Bob Sigafoos. In 1959, Hopkins‘⁹ long years of work led him to publish his first major paper on the Bering land bridge. In it he theorised about the first formation of a land bridge in the Miocene, its first inundation at the Miocene-Pliocene boundary and its continued cyclic formation and submergence during the Pleistocene. Casting his mind back to that time Hopkins comments¹⁰ that “..it suddenly occurred to me that if we three got together we could perhaps solve the problem of the Bering Land Bridge. We could show whether it existed or not and when it existed or not .. The Land Bridge was in the air. It had been for years.”
Whilst not all of his peers accepted these theories, he was fast becoming the best known and widely published figure in Bering land Bridge research.
Thus it may not seem surprising, that in 1963 he was asked by the International  Association for Quarternary Research to organise an all-day symposium on the land bridge for the 1965 INQUA conference.
This galvanised him to begin reaching out to Russian scientists such as Merklin and Petrov and others to request paper proposals for the upcoming symposium. The back and forth of distributing drafts to symposium participants, the insistence that contributors consider and comment on others’ work and address it in print before the symposium, and the judicious editing of the papers ended up with the event being one of the best organised and productive ever organised. It has since been held up as an example of best practice in organising such events. In the year of the symposium it also led Hopkins to jointly publish 1965 published a paper with Merklin and Petrov and other U.S. scientists¹¹.
The work however had only just begun. Now the symposium and it’s papers needed to be organised and published for their full import to be realised. Hopkins set to work with relish. After two years he had edited the monumental tome “The Bering Land Bridge”. It was published in 1967. Hopkins of course, personally wrote the summary chapter¹².  

 

Hopkins on publication day.

Photo Credit O’Neill¹⁰

 

 

Cover of the ‘Bible’ as colleagues began to call the Bering Land Bridge.

Photo credit N Barden

 

The results presented from many different disciplines and by scientist worldwide and their subsequent analysis and synthesis by Hopkins represented a huge step forward in the understanding of the Bering Land Bridge. In summary the results were:

 

·         During the Pleistocene Era (2 million years ago to 10 000 years ago), Beringia was a large, ice-free land mass during periods of glaciation

·         As the climate warmed and the glaciers melted, the Bering-Chukchi platform would flood, severing the terrestrial connection between North America and Asia. Eventually, the climate cooled and glaciers reformed, exposing the Bering Land Bridge again.

·         When exposed, this land bridge was covered with vegetation and supported a variety of animal life

·         That 4 waves of mammalian immigration had occurred over the land bridge, once during early Miocene, again at the Pliocene-Pleistocene boundary and probably at least twice more during Pleistocene. Furthermore the climate on the land bridge appeared to be temperate, humid and forested in the first two episodes, temperate grasslands in the mid Pleistocene and only in late Pleistocene was the climate significantly colder being represented by tundra, steppe and Taiga plant communities. Additionally there was some back migration from the Americas to Asia.

·         That the land bridge had existed at least nine times during the Pleistocene

 

Table by Reppening showing envisaged mammalian migrations during the late Pliocene and Pleistocene¹³

 

Whilst a huge amount of the work was accepted by the scientific community at large many questions remained for Hopkins. For example was it possible to reconstruct the ancient climate on and near the land bridge and more particularly could he reconstruct the climate during the LAST land bridge. For this it was assumed would allow basic questions about the peopling of the Americas to be, at last, definitively answered.

 

During the editing of The Bering land Bridge in 1966, Hopkins did not forsake his usual Alaskan, summer field season. Whilst camped on the north shore of the Seward peninsula, Dale Guthrie and John Matthews turned up to study fossil insects in sedimentary deposits that Hopkins had previously recommended to them at the adjacent, Cape Deceit on Kotzebue Sound. As Hopkins says¹⁰: “I had reason to think that Cape deceit had a record that went at least back through the last glaciation, the IIlinoian. I had no idea that it would go back, possibly, to the Pliocene.. They started digging at Cape Deceit, which turned out to be one of the most important contributions ever to Beringian Paleoecology.” The Pliocene/Pleistocene boundary fossil faunal were presented in The Bering land Bridge, a year later by Reppening¹³. It was not these fossils, impressive as they were, however, that were of key importance. It was the fossil pollen, plant fragments and body parts of assorted insects that were the real goldmine. For it was in these, that scientist could start to reconstruct the paleoclimate of the Bering Land Bridge. Their work indicated that the early Pleistocene climate in the region had been a dry, scantily clad Tundra which became grassland dominated in mid-Pleistocene and Steppe Tundra at the end of the geologic period and that in warmer interglacials treelines had been considerably further west, and in fact as far west as Cape Deceit, on at least two occasions. In other words there were considerable periods, during which, the migration of large herbivores such as mammoths and presumably their human hunters could have crossed the land bridge throughout the Pleistocene.

This view of the paleoecology of Beringia was not shared by all, however. Another of Hopkins’ associates Paul Colinvaux, had, at Hopkins’ suggestion had carried out sediment coring at Imuruk Lake. The view of the paleoecology of Beringia he drew from the fossil pollen record was in stark contrast to that of Guthrie and Matthews. He viewed Beringia as an  , a windy, forsaken landscape of sparse tundra, “a dusty plain stretching to the horizon, vegetated between the bare patches with a low mat of sedges and grasses looking like a drier version of the modern arctic plain.”¹⁴

Twelve years after the publication of his first book Hopkins arranged a second conference to discuss the current work of the Paleoecology of Beringia, the Wenner-Gren Foundation for Anthropological Research Symposium was held June 8-17, 1979 in Burg Wartenstein Austria. The resulting book¹⁵, The Paleoecology of Beringia was published in 1982.

 

The publication, caused, what has become the longest running argument in Beringian studies. Ritchie and Cwynar stated, in 1982¹⁸ that “We suggest that the ‘Arctic Steppe Biome’ never existed”. Also critical of the productive Mammoth Steppe theory was Collinvaux and West’s 1984¹⁴ view of the Beringian Paleoecology. This was swiftly followed in 1985¹⁶ by Guthrie with his provocatively titled “Woolly Arguments Against the Mammoth Steppe”. Colinvaux’s 1986 reply¹⁷ was equally biting. The situation became so bad that Guthrie is reputed to have dumped a huge, muddy, freshly dug mammoth tusk on Colinvaux’s desk and heatedly told him that he had dated Mammoth remains spanning the whole of the existence of the Bering land Bridge. Colinvaux was unimpressed and continued to insist (in print) that these skeletal remains were the result of migrations of mammoth from distant productive areas. Guthrie’s response “They have to eat every 12 hours!” and evidence in the form of the grass and herbaceous gut contents of mammoth remains sealed in permafrost from Siberia fell on deaf ears.  

 

What was needed was more evidence to demonstrate one way or another whether Beringia was a cold, unproductive arctic desert, or a rich Mammoth Steppe with herbaceous vegetation capable of supporting large herds of grazing animals. Unsurprisingly some of the evidence was actually and literally uncovered by Hopkins himself. In 1988, following up on a 1974 observation of what he believed to be a preserved Pleistocene ground surface, he took his graduate students Claudia Hofle and Victoria Goetcheus to the Devil Mountain-Cape Espenberg area. Here, sealed by a layer of volcanic tephra, they uncovered actual preserved remains of a rich array of herbaceous plants, shrubs and grasses. Furthermore, radiocarbon dating of the remains gave a date of 18000BP, i.e. in the middle of the period disputed by the Palynologists, Colinvaux and Ritchie on one hand and Guthrie and Young on the other. This supported the Mammoth Steppe theory. Later publications by Hofle^{23a and b} and Goetcheus^{24a and b} confirmed this.

 

Further evidence came to light from Cinq-Mars’ excavation of the Blue Fish Caves¹⁹ in the Yukon. Cinq-Mars states:

“More importantly, these results demonstrate that the mammoth steppe.. constituted an essential element of the Glacial Maximum biotope of eastern Beringia (between about 17,000 and 25,000 BP).”

Basically Cinq-Mars is saying that their palynological and other data show that Mammoth Steppe did exist at the time of the sediment formation over height of the last glacial maxima (ca. 22000BP). In other words their data refute the “productivity paradox” of Schweger et al.²⁰ (1982) and the position of Cwynar and Ritchie (1980)²¹ and support the position of Guthrie (1985)¹⁶ and Matthews (1982)²² that the environment was extremely rich and capable of supporting an extensive megafaunal assemblage.

 

Further publications, including Guthrie 2001²⁵ have thus stabilised the view that the Mammoth Steppe had actually existed as suggested and was capable supporting large Pleistocene grazing fauna which, in turn, were followed into the new world by humanity.

 

Here Hopkins’ direct involvement of the investigations of the Bering Land Bridge ends. He died aged 79, in November 2001.

 

Research has of course, continued. In fact Hopkins’ hypothesis in 1967 that the Bering Land Bridge had existed at least nine times has been updated by workers such as Pielou (1991) who theorises²⁶ that the Bering Land bridge has existed at least 20 times during the Pleistocene.

 

The Bering land Bridge at the height of the Illinoian glaciation. From Hopkins¹² p462

 

 

 

The Bering land Bridge at the height of the Wisconsin glaciation. From Hopkins¹² p462

 

References

1. Joseph de Acosta, Edward Grimston, Clements Robert Markham, The Natural and Moral Historie of the Indies, Hakluyt Society, 1880 pp.i-ii

 

2. Wallace, H. R. 1876. The geographical distribution of animals: harper, New York 2 vols.

 

3. Dawson, G. M. (1898). Geologic notes on some of the coasts and islands of Bering Sea and vicinity: Geol. Soc. American Bulletin., v.5 p117-146

 

4. Osborn, H. F. 1909. Cenozoic mammal horizons of western North America: US Geol. Survey Bull. 361 138p.

 

5. Willis, Bailey. 1909. Paleogeographic maps of North America: 13, Eocene-Oligocene North America: Jour. Geology v.17 p506-508; Quarternary North amerioca: Jour. Geology v17 p600-602

 

6. Simpson, G. G. 1947. Holarctic mammalian faunas and continental relationships during the Cenezoic: Geol. Soc. America Bull., v.58 p.613-687

 

7. Daly, R.A. 1934. The changing world of the Ice Age: Yale Univ. Press, 271p.

 

8. Hulten, Eric. 1937. Outline of the history of arctic and boreal biota during the Quarternary Period: Bokforlags Aktiebolaet Thule, Stockholm, 168 p.

 

9. Hopkins, D.M. 1959. Cenozoic history of the Bering Land Bridge. Science, 129, 1519–1528.

 

10. O’Neill, D. 2004. In The Last Giant of Beringia. Westview Press Boulder Colorado p. 107

 

11. Hopkins, D.M., MacNeil, F.S., Merklin, R.L. and Petrov OM (1965) Quaternary correlations across Bering Strait. Science, 147, 1107–1114.

 

12. Hopkins, D.M. 1967. The Cenozoic history of Beringia—A Synthesis., in The Bering Land Bridge Hopkins, D.M, ed. Stanford University Press.

 

13. Reppening, C. 1967 Palearctic-Nearctic Mamalian Dispersal in the Late Cenozoic. In The Bering Land Bridge Hopkins, D.M, ed. Stanford University Press.

 

14. Colinvaux, Paul A. and Frederick H. West. 1984. The Beringian Ecosystem. The Quarterly Review of Archaeology, Sept issue 1984.

 

15. Hopkins, D.M., Matthews, J.V., Schweger, C.E. and S.B. Matthews. 1982. The Paleoecology of Beringia. Wenner-Gren Foundation for Anthropological Research. Symposium. New York : Academic Press.

 

16. Guthrie, R. Dale. 1985. Woolly Arguments Against the Mammoth Steppe - A new look at the Palynological Data. The Quarterly Review of Archaeology, Sept 1984.

 

17. Colinvaux, Paul, A. 1986. Plain Thinking on Bering land Bridge Vegetation and Mammoth Populations. The Quarterly Review of Archaeology, March 1986. 

 

18. Ritchie, J.C. and L. Cwynar. 1982. “The Late Quaternary Vegetation of the North Yukon.” In: Paleoecology of Beringia, ed. D.M. Hopkins et al. (New York, Academic Press) pp. 113-126.

 

19. Cinq-Mars, Jacques and Richard E. Morlan. 1999. “Bluefish Caves and Old Crow Basin: A New Rapport,” in Ice Age Peoples of North America, ed. by Robson Bonnichsen and Karen L. Turnmire, pp. 200-212. Corvallis: Oregon State University Press for the Center for the Study of the First Americans.

 

20. Schweger, C.E., J.V. Mathews, Jr., D.M. Hopkins and S.B. Young (eds.) 1982.

“Paleoecology of Beringia – A Synthesis.” In: Paleoecology of Beringia, ed. D.M. Hopkins et al. (New York, Academic Press) pp. 425-444.

 

21. Cwynar, L. and J.C. Ritchie.1980. Arctic steppe-tundra: A Yukon perspective. Science Vol. 208, pp. 1375-1377.

 

22. Matthews, J.V., Jr. 1982. East Beringia during Late Wisconsin Time: A Review of the Biotic Evidence. In: Paleoecology of Beringia, ed. D.M. Hopkins et al. (New York, Academic Press) pp. 127-150.

 

23a. Hoefle, C. L. Buried Soils on Seward Peninsula, Northwest of the Bering Land Bridge. Masters thesis, University of Alaska Fairbanks, August 1995.

 

23b. C. Hoefle, C. L. Ping, D. Mann and M. Edwards

Buried Soils on Seward Peninsula: A Window into the Paleoenvironment of the Bering Land Bridge. Current Research in the Pleistocene Vol. 11, 1994.

 

24a. Goetcheus, Victoria G. 1995. The vegetation of A 17 Buried Surface on the Northern Seward Peninsula. 24^th Artic Workshop, Quebec. Abstracts, 1995.

 

24b. V. G. Goetcheus, D. M. Hopkins, M. E. Edwards and D. H. Mann

Window on the Bering Land Bridge: A 17,000-year-old Paleosurface on the Seward Peninsula, Alaska Current Research in the Pleistocene Vol. 11, 1994

 

25. Guthrie, Dale. R. 2001. Origin and causes of the mammoth steppe: a story of cloud cover, woolly mammal tooth pits, buckles, and inside-out Beringia

Quaternary Science Reviews 20 ps.549-574

 

26. Pielou, E.C. 1991.  After the Ice Age: The Return of Life to Glaciated North America. University of Chicago Press, Chicago