Sort order:  

Status: 1 Treffer   •   Seite 1 von 1   •   10 Artikel pro Seite

2016-09-10 14:01:55   •   ID: 1504

Quartz during the Paleolithic: More important than usually assumed

Figure 1
This is a small discoidal handaxe from the Mousterian site at Kervouster (6x5x2 cm) made from Microcrystalline Quartz (Fig. 1, Fig. 2&3 showing the translucent character of the piece). The site and is putatively dated to MIS 3.

The industry is assigned to a Mousterian with Bifacial Tools, MBT, a term coined by Karen Ruebens some years ago.

The principal characteristic of the MBT at Kervouster is the preferential bifacial treatment, with most of the industry made from flake supports. The main raw material for the production of bifacial tools at Kervouster was a fine grained glossy sandstone.

Figure 2
Among the thousands of artifacts; only a handful were made from translucent Quartz, as the one shown here. “Quartz” is a term that includes both well crystallized and compact forms of silica.

All varieties are chemically the same substance, silicon dioxide, SiO2 also known as silica (from the Latin: Silex). Silica is one of the hardest and most common materials in the Earth’s crust.

Due its ubiquitous availability it always played a role as raw material during the Stone Age and beyond- if you remember most computer microchips are currently made from SiO2 due to its effective semi-conducting properties.

Figure 3
For a long time the classification of Quartz was mostly based on the visual appearance and the possibility to resolve structural elements in an optical microscope.

Today the petrographic characterization is complemented by X-ray diffraction, Scanning Electron Microscopy, and Energy Dispersive X-ray analysis. Microcrystalline varieties that develop visible crystals or are made of large intergrown crystals: Rock crystal, Citrine, Milky Quartz, Rose Quartz and others, while the dense and compact forms are called Cryptocrystalline Quartz (Chert, Flint, Chalcedony and others).

It is astonishing that one chemical compound can have several different appearances such as a “Berg Crystal” and Flint. Quartz fractures are less predictably relative to other raw materials and have a tendency to shatter and fragment. In addition, Quartz requires different techniques and tools than are normally used to knap flint or chert.

There seems to be a prolonged learning curve for the knappers know how to produce predictable flakes and blades compared to task of knapping flint.

There is almost no scientific literature about this theme and no systematic review about the use of Quartz during the Paleolithic so far I know.

The Perception of the role that Quartz once played on lithic economies may be biased to a certain degree, especially by a selection bias of excavations until the late mid-20th century.

Discussing his recent research in Portugal, Almeida (2006) noted that data from earlier excavations in Portugal were difficult to use in analyses because most of the non-flint materials were discarded, along with the smaller artefacts.

Especially, European Archaeologists have only recently recognized Quartz as a significant part of prehistoric stone technologies. Quartz is abundant in many areas and was utilized extensively during prehistory.

However, research biases have obscured a fuller understanding of it, with the evidence either having been overlooked or ignored. Often dismissed as a poor alternative to flint, and impossible to analyse due to perceived irregular fracture properties, quartz is best understood as a different material with different physical characteristics to cryptocrystalline materials such as flint and chert that were used in prehistory.

Africanists, on the other hand were always aware of the importance of Quartz even during the earliest Paleolithic. Quartz is common during the Oldowan in East Africa.

A Comparison of the geological and archaeological samples at Gona, dated to about 2, 6 Mya, clearly demonstrates a high degree of raw material selectivity exercised by the hominids at this site.

The excavators noticed a clear preference for felsic volcanic rocks, using them in much greater proportion than would be expected from their representation in the gravels.

Quartz, on the other hand was preferably used by Late Pliocene toolmakers (ca. 2, 3 Mya) in assemblages from the Omo Shungura Member F, where its frequency is most probably a reflection of local availability and not of deliberate choice.

Figure 4
At Olduvai, Bed I (1,85–1, 70 Mya), the archaeological assemblages are dominated by volcanic cobbles from local paleochannels. These cobbles appear to have been selected for size and their lithic composition.

In Bed II (1, 7 Mya), assemblages show a clear tendency toward the increased use of quartz and exotic volcanic rocks. Causes underlying the increased selective use of quartz over time remain unclear, and may include changes in raw material availability, hominid ranging patterns and tool using behaviours.

The use of quartz persisted during the East and North African Acheulian and east African MSA. A wonderful ca 1mya k.a. old small handaxe from Bed IV in Olduvai Gorge is shown at the British Museum Olduvai Handaxe .

Figure 4 shows a 20 cm long translucent Quartz cleaver from Tihodaine (Tassili n’Ajjer). Here the Acheulean artefacts are associated with interglacial fauna at the playa of a Paleolake. In general, Quartzite, Quartz and Rhyolite were used as raw materials.

Raw material selectivity of early Homo sapiens can be nicely demonstrated from the MSA in South Africa.

At Sibudu Cave, the presence of quartz backed tools is restricted to the lower and middle part of the Howiesons Poort sequence (MIS4) These implements are smaller, and not as highly standardized than backed tools made from other rock types. Quartz backed tools are recorded in other HP sites in South Africa, for example, Klasies River and Umhlatuzana Rock Shelter.

Figure 5
Interestingly, a preferential use of Quartz is not restricted to the Howiesons Poort, as the most common rock type in “post- Howiesons Poort assemblages“ at Sibudu is Quartz.

Figure 5 shows an extraordinary appealing MSA point made from Microcrystalline Quartz from Melka Kunture-Garba III / Ethiopia, which is at least 120 k.a. old.

The Garba III industry is based on Levallois operational sequences. The archaeological evidence towards MSA from Garba III, together with a few other finding related to this same geological time period, currently represent at Melka Kunture the only MSA occurrences, which are otherwise, in Eastern Africa, rather common.

A Quartz artifact from Garba III, is a rare finding, as a wide range of finer grained lavas and obsidian, played the most important role in raw material procurement on this site .

During the 19th and early 20th century, in Europe Rock crystal was occasionally recognized, from the Mousterian in S/W-France (Les Merveilles and Laussel in the Dordogne, La Chapelle-aux-Saints and Chez-Poure in the Corrèze). Rock crystal Solutrean leaf points are known from Le Placard (Charente), and from the rock shelter of Badegoule (Dordogne).

Rock crystal was also used during the Hungarian Epigravettian and during the Magdalenian at Zitny, Kulna and Pekarna caves in Moravia and during the late Magdalenien of the Gudenus cave in Lower Austria.

In Iberia there are a lot of Middle Paleolithic sites with the preferential use of Quartz like the recently published microlithic Mousterian from Navalmaíllo, dated to MIS4.

Other examples are known from Catalonia at Cueva 120 level G ; Avellaners and Diable Coix (Comarca de la Selva, Girona); Arbreda (Serinyà, Girona) level H-43 and many more. Up to 91% of the artifacts at these sites are made on Quartz.

Similar sites are also known from France, beginning with the Quartz tools, that are part of the Lower Paleolithic industries of the Garonne and Roussillon terasses and from cave sites like Arago.

The most important question, what made Quartz so attractive for our ancestors has not been answered up to now. What characteristic of this material made them not to use high quality flint from the vicinity of their camps but instead Quartz, sometimes from a 20-30km distance?

Theoretically Chert is somwath an optimal raw material by its homogeneity, ability to develop high quality conchoidal fracture, and the production of exceptionally sharp edges. Anyhow, compared to other raw materials, the flake edges are often less less durable. This may have necessitated more frequent retouching to strengthen the edges of chert flakes. This thesis would need experimental confirmation.

Maybe one of my readers knows the answer…