Friday, 15 January 2016

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)




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