Blombos Cave
Encyclopedia
Blombos Cave is a cave
Cave
A cave or cavern is a natural underground space large enough for a human to enter. The term applies to natural cavities some part of which is in total darkness. The word cave also includes smaller spaces like rock shelters, sea caves, and grottos.Speleology is the science of exploration and study...

 in a calcarenite
Calcarenite
thumb|250px|The [[Pietra di Bismantova]] in central [[Italy]] is an example of calcarenite formation.Calcarenite is a type of limestone that is composed predominately, more than 50 percent, of detrital sand-size , carbonate grains...

 limestone
Limestone
Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....

 cliff on the Southern Cape coast in South Africa
South Africa
The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...

. It is an archaeological
Archaeology
Archaeology, or archeology , is the study of human society, primarily through the recovery and analysis of the material culture and environmental data that they have left behind, which includes artifacts, architecture, biofacts and cultural landscapes...

 site made famous by the discovery of 75,000-year-old pieces of ochre
Ochre
Ochre is the term for both a golden-yellow or light yellow brown color and for a form of earth pigment which produces the color. The pigment can also be used to create a reddish tint known as "red ochre". The more rarely used terms "purple ochre" and "brown ochre" also exist for variant hues...

 engraved with abstract designs and bead
Bead
A bead is a small, decorative object that is usually pierced for threading or stringing. Beads range in size from under to over in diameter. A pair of beads made from Nassarius sea snail shells, approximately 100,000 years old, are thought to be the earliest known examples of jewellery. Beadwork...

s made from Nassarius
Nassarius
Nassarius, common name nassa mud snails or dog whelks , is a genus of minute to medium-sized sea snails, marine gastropod molluscs in the family Nassariidae. -Etymology:...

shells, and c. 80,000-year-old bone tool
Bone tool
Bone tools have been documented from the advent of Homo sapiens and are also known from Homo neanderthalensis contexts or even earlier. Bone is a ubiquitous material in hunter-gatherer societies even when other tool materials were not scarce or unavailable...

s. Some of the earliest evidence for shellfishing and possibly fishing
Fishing
Fishing is the activity of trying to catch wild fish. Fish are normally caught in the wild. Techniques for catching fish include hand gathering, spearing, netting, angling and trapping....

 has been discovered at the site and dates to c. 140,000 years ago.

Introduction

Excavations carried out since 1991 at Blombos Cave provide snapshots of life in the African Middle Stone Age
Middle Stone Age
The Middle Stone Age was a period of African Prehistory between Early Stone Age and Late Stone Age. It is generally considered to have begun around 280,000 years ago and ended around 50-25,000 years ago. The beginnings of particular MSA stone tools have their origins as far back as 550-500,000...

 (MSA) in the southern Cape,
South Africa
South Africa
The Republic of South Africa is a country in southern Africa. Located at the southern tip of Africa, it is divided into nine provinces, with of coastline on the Atlantic and Indian oceans...

. Three phases of MSA occupation have been identified and named M1, M2 and M3. Dating by the optically stimulated luminescence
Optically stimulated luminescence
In physics, optically stimulated luminescence is a method for measuring doses from ionizing radiation.The method makes use of electrons trapped between the valence and conduction bands in the crystalline structure of certain types of matter . The trapping sites are imperfections of the lattice -...

 (OSL) and thermoluminescence
Thermoluminescence
Thermoluminescence is a form of luminescence that is exhibited by certain crystalline materials, such as some minerals, when previously absorbed energy from electromagnetic radiation or other ionizing radiation is re-emitted as light upon heating of the material...

 (TL) methods have provided occupation dates for each phase: these are about 71,000 BCE
Common Era
Common Era ,abbreviated as CE, is an alternative designation for the calendar era originally introduced by Dionysius Exiguus in the 6th century, traditionally identified with Anno Domini .Dates before the year 1 CE are indicated by the usage of BCE, short for Before the Common Era Common Era...

 for the M1 phase, about 78,000 BCE for the M2 phase, and between 100,000 and 140,000 BCE for the M3 phase.

The evidence indicates periods of relatively brief occupation separated by long periods of non-occupation, including a separation between occupation during the Late Stone Age
Late Stone Age
The Later Stone Age refers to a period in African prehistory. Its beginnings are roughly contemporaneous with the European Upper Paleolithic...

 (LSA) and the Middle Stone Age. Bone tools, marine shell beads, and engraved ochre were found in the M1 phase, bone tools in the Upper M2 phase, and considerable quantities of ochre and associated ochre working tools in the M3 phase.

Excavation history and stratigraphy

Blombos Cave is some 100 metres (328.1 ft) from the coast and 35 metres (114.8 ft) above sea level. The cave is a wave-cut bench in Mio
Miocene
The Miocene is a geological epoch of the Neogene Period and extends from about . The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words and and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene follows the Oligocene...

/Pliocene
Pliocene
The Pliocene Epoch is the period in the geologic timescale that extends from 5.332 million to 2.588 million years before present. It is the second and youngest epoch of the Neogene Period in the Cenozoic Era. The Pliocene follows the Miocene Epoch and is followed by the Pleistocene Epoch...

 Wankoe Formation aeolian deposits. Interior cave deposits, including those in recesses, cover more than 80 square metres (861.1 sq ft). About 20 square metres (215.3 sq ft) of the MSA has been excavated to a depth of about 2 metres (6.6 ft) below the original surface. The depositional history of the MSA levels is complex. Probably just prior to the accumulation of the M3 phase large calcrete roof blocks up to 3 metres (9.8 ft) thick were dislodged creating a variable and uneven floor surface. Further rockfall onto the MSA deposits occurred after the M3 phase occupation at circa 130-140 ka.

Subsequent human occupation left debris scattered over and around these blocks up to a height of more than 2 metres (6.6 ft). Compaction has caused deposits to drape over and around large spall
Spall
Spall are flakes of a material that are broken off a larger solid body and can be produced by a variety of mechanisms, including as a result of projectile impact, corrosion, weathering, cavitation, or excessive rolling pressure...

s with some examples of near vertical layering. Near the rear and side cave wall MSA deposits have in some instances shrunk leaving a gap that later filled with LSA deposits. In places large rocks have shifted or broken causing shearing of deposits and infills. Despite these anomalies most MSA deposits are in situ and undisturbed. By identifying and excluding material from contaminated areas archaeologists are confident of the integrity of more than 95 per cent of recovered MSA material.

Artifacts and fauna

Principal markers of the M1 phase are bifacial foliate points, typical of the Stillbay
Stillbay
The Stillbay industry is the name given by the archaeologists Goodwin and van Riet Lowe in 1929 to a mid-Palaeolithic stone tool manufacturing style after the site of Stilbaai in South Africa where it was first described. It may have developed from the earlier Acheulian types...

, both complete and in various stages of manufacture. More than 400 have been recovered. Silcrete
Silcrete
Silcrete is an indurated soil duricrust formed when silica is dissolved and resolidifies as a cement. It is a hard and resistant material, and though different in origin and nature, appears similar to quartzite...

 is the dominant raw material and the nearest source is circa 30 kilometres (18.6 mi). Large numbers of small flakes occur indicating on-site production of these artifacts. Some of the points show fractures which were interpreted as the result of their use as spear points. According to an experimental study of the points, shaping of the points could have been achieved through pressure flaking, a technique that was previously believed to appear first in Europe 20,000 years ago as part of the Solutrean
Solutrean
The Solutrean industry is a relatively advanced flint tool-making style of the Upper Palaeolithic, from around 22,000 to 17,000 BP.-Details:...

 toolkit.

More than 60 bead
Bead
A bead is a small, decorative object that is usually pierced for threading or stringing. Beads range in size from under to over in diameter. A pair of beads made from Nassarius sea snail shells, approximately 100,000 years old, are thought to be the earliest known examples of jewellery. Beadwork...

s manufactured from Nassarius
Nassarius
Nassarius, common name nassa mud snails or dog whelks , is a genus of minute to medium-sized sea snails, marine gastropod molluscs in the family Nassariidae. -Etymology:...

 kraussianus
gastropod shells have been recovered. Twenty-seven of these beads may derive from a single personal ornament. Two chunks of ochre
Ochre
Ochre is the term for both a golden-yellow or light yellow brown color and for a form of earth pigment which produces the color. The pigment can also be used to create a reddish tint known as "red ochre". The more rarely used terms "purple ochre" and "brown ochre" also exist for variant hues...

 engraved with geometric patterns and more than 15 bone tools come from the M1 phase. M2 phase markers are the more than 20 bone tools and a marked reduction in bifacial technology. In the M3 phase bifacial flaking and bone tools disappear. Silcrete is still dominant but there are fewer retouched tools. Striated ochre, particularly in large chunk form, is common in these levels. Ochre processing tools include lower and upper grindstone
Grindstone
Grindstone may refer to:*Grindstone , a tool used for sharpening*Grindstone, a type of millstone used to grind grains such as wheat*Grindstone , 1996 Kentucky Derby winner and sire of the racehorse Birdstone...

s and hammerstone
Hammerstone
In archaeology, a hammerstone is a hard cobble used to strike off lithic flakes from a lump of tool stone during the process of lithic reduction. The hammerstone is a rather universal stone tool which appeared early in most regions of the world including Europe, India and North America...

s. Dense shellfish middens characterize the lower layers with very large hearth
Hearth
In common historic and modern usage, a hearth is a brick- or stone-lined fireplace or oven often used for cooking and/or heating. For centuries, the hearth was considered an integral part of a home, often its central or most important feature...

s.

Faunal remains from the three MSA phases show that a wide range of terrestrial resources were exploited. More than a thousand fish bones, many from large fish, marine shells, seals
Pinniped
Pinnipeds or fin-footed mammals are a widely distributed and diverse group of semiaquatic marine mammals comprising the families Odobenidae , Otariidae , and Phocidae .-Overview: Pinnipeds are typically sleek-bodied and barrel-shaped...

 and dolphin
Dolphin
Dolphins are marine mammals that are closely related to whales and porpoises. There are almost forty species of dolphin in 17 genera. They vary in size from and , up to and . They are found worldwide, mostly in the shallower seas of the continental shelves, and are carnivores, mostly eating...

s attest to extensive exploitation of aquatic resources and suggest exploitation patterns not dissimilar to that of LSA people in this region. Nine human teeth, mostly deciduous, have been recovered from the MSA levels but no other human skeletal material. The teeth probably derive from fairly gracile individuals and are similar to samples recovered at Klasies River Caves
Klasies River Caves
The Klasies River Caves are a series of caves located to the east of the Klasies River mouth on the Tsitsikamma coast in the Humansdorp district of Eastern Cape Province, South Africa. The three main caves and two shelters at the base of a high cliff have revealed evidence of middle stone...

 and De Kelders
De Kelders
De Kelders is a coastal village in the Overberg District Municipality, Western Cape, South Africa....

.

Engraved ochre and its interpretation

The Blombos Cave people engraved pieces of ochre are regarded as the oldest known artwork but very much simpler than the cave paintings and figurines found in Europe after 40,000 BP
Before Present
Before Present years is a time scale used in archaeology, geology, and other scientific disciplines to specify when events in the past occurred. Because the "present" time changes, standard practice is to use AD 1950 as the origin of the age scale, reflecting the fact that radiocarbon...

.

The date of engraved ochre is now firmly established. The use of abstract symbolism on the engraved pieces of ochre and the presence of a complex tool kit suggests Middle Stone Age
Middle Stone Age
The Middle Stone Age was a period of African Prehistory between Early Stone Age and Late Stone Age. It is generally considered to have begun around 280,000 years ago and ended around 50-25,000 years ago. The beginnings of particular MSA stone tools have their origins as far back as 550-500,000...

 people were behaving in a cognitively modern way and had the advantages of syntactical language at least 80,000 years ago.

Remains

Human remains from the cave include four teeth found in 1998, of which two are heavily worn deciduous teeth and two are incomplete permanent premolar crowns. Marks on the premolars may indicate the use of toothpick
Toothpick
A toothpick is a small stick of wood, plastic, bamboo, metal, bone or other substance used to remove detritus from the teeth, usually after a meal. A toothpick usually has one or two sharp ends to insert between teeth. They can also be used for picking up small appetizers or as a cocktail...

s. Another five dental specimens were unearthed in the cave during 1999–2000

Tools

In 2010, a study headed by Vincent Mourre under the auspices of the University of Toulouse
University of Toulouse
The Université de Toulouse is a consortium of French universities, grandes écoles and other institutions of higher education and research, named after one of the earliest universities established in Europe in 1229, and including the successor universities to that earlier university...

 found evidence that prehistoric humans had used the technique of pressure flaking to shape stone into tools. The researchers said that the remains of stone points, likely used as spear points or knives, that were carved using pressure flaking had been found that were around 75,000 years old. Previously, it had been believed that pressure flaking had only been invented around 20,000 years ago, in parts of France. The study examined 127 separate artifacts, all made from silcrete
Silcrete
Silcrete is an indurated soil duricrust formed when silica is dissolved and resolidifies as a cement. It is a hard and resistant material, and though different in origin and nature, appears similar to quartzite...

, a difficult material to work with, especially compared to flint
Flint
Flint is a hard, sedimentary cryptocrystalline form of the mineral quartz, categorized as a variety of chert. It occurs chiefly as nodules and masses in sedimentary rocks, such as chalks and limestones. Inside the nodule, flint is usually dark grey, black, green, white, or brown in colour, and...

, which was the rock in which previous evidence of pressure flaking had been found. Out of the 127 points found, around three-fifths appeared to have been produced using pressure flaking.

According to an official at the University of Colorado Museum of Natural History
University of Colorado Museum of Natural History
The University of Colorado Museum of Natural History is a museum of natural history in Boulder, Colorado. With more than four million artifacts and specimens in the areas of anthropology, botany, entomology, paleontology and zoology, the museum houses one of the most extensive and respected...

, Paola Villa, the French team's discovery was "important because it shows that modern humans in South Africa had a sophisticated repertoire of tool-making techniques at a very early time." However, Curtis Marean, an archaeologist from the Arizona State University
Arizona State University
Arizona State University is a public research university located in the Phoenix Metropolitan Area of the State of Arizona...

, said that although the results are plausible he remains unconvinced that the researchers had based their conclusions on mathematical data, expressing concerns that the results were too reliant on more subjective observations of the tools discovered.

Mourre's University of Toulouse
University of Toulouse
The Université de Toulouse is a consortium of French universities, grandes écoles and other institutions of higher education and research, named after one of the earliest universities established in Europe in 1229, and including the successor universities to that earlier university...

 study follows upon the earlier 2008 Stillbay
Stillbay
The Stillbay industry is the name given by the archaeologists Goodwin and van Riet Lowe in 1929 to a mid-Palaeolithic stone tool manufacturing style after the site of Stilbaai in South Africa where it was first described. It may have developed from the earlier Acheulian types...

 study by Zenobia Jacobs, of the University of Wollongong
University of Wollongong
The University of Wollongong is a public university located in the coastal city of Wollongong, New South Wales, Australia, approximately 80 kilometres south of Sydney...

, Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...

 who dated Still Bay silcrete
Silcrete
Silcrete is an indurated soil duricrust formed when silica is dissolved and resolidifies as a cement. It is a hard and resistant material, and though different in origin and nature, appears similar to quartzite...

 tools at 71,000-71,900 years BP (Before Present
Before Present
Before Present years is a time scale used in archaeology, geology, and other scientific disciplines to specify when events in the past occurred. Because the "present" time changes, standard practice is to use AD 1950 as the origin of the age scale, reflecting the fact that radiocarbon...

), pushing the culture's advent back a further few thousand years if Mourre's team's dating is accepted.

Palaeoenvironment

The M1 phase (oxygen isotope stage 5a/4) occupation occurs during a period of falling sea levels (c. 60 – below present sea levels and 10 – from present coastline) that is arguably colder than during M2. Donax serra, a sand burrowing white mussel, occurs in the M1 phase suggesting beach conditions in front of the cave. Densities of shell are lowest in this phase (17.5 kg/m3) probably because of the distance of the coast from the cave. M2 phase occupations fall within OI 5a with sea levels circa 25 metres (82 ft) lower than present and a coastline less than 5 kilometres (3.1 mi) from the present shore. Intermediate densities of shell occur in M2 (31.8 kg/m3). Climatic conditions may have been temperate and warmer than during M1 occupations. The upper part of the M3 phase (CH/CI layers) is a high density shell midden (68.4 kg/m3) suggesting sea levels similar to the present. These upper levels arguably fall just after the Eemian period (OI 5d; c. 100 ka. Temperatures were probably 1 to 2 °C (2 to 4 °F) warmer than present with higher sea levels (+3 m or +10 ft). An OSL date of c. 143 ka (OI 6) for a low density occupation level (layer CJ) in M3 suggests the M3 phase may need further subdivision when more dates are available.

See also

  • Behavioral modernity
    Behavioral modernity
    Behavioral modernity is a term used in anthropology, archeology and sociology to refer to a set of traits that distinguish present day humans and their recent ancestors from both living primates and other extinct hominid lineages. It is the point at which Homo sapiens began to demonstrate a...

  • List of caves in South Africa
  • Howieson's Poort Shelter
  • Enkapune Ya Muto
    Enkapune Ya Muto
    Enkapune Ya Muto, also known as Twilight Cave, is a Late Stone Age site on the Mau Escarpment of Kenya. Beads made of perforated ostrich egg shells found at the site have been dated to 40,000 years ago. The beads found at the site represent some of the earliest known personal ornaments.-External...

  • Prehistoric art
    Prehistoric art
    In the history of art, prehistoric art is all art produced in preliterate, prehistorical cultures beginning somewhere in very late geological history, and generally continuing until that culture either develops writing or other methods of record-keeping, or it makes significant contact with another...

  • Symbolic culture
    Symbolic culture
    Symbolic culture is a concept used by archaeologists, social anthropologists and sociologists to differentiate the cultural realm constructed and inhabited uniquely by Homo sapiens from ordinary "culture", which many other animals possess. Symbolic culture presupposes more than the ability to learn...

  • Timeline of evolution
    Timeline of evolution
    This timeline of evolution of life outlines the major events in the development of life on planet Earth since it first originated until the present day. In biology, evolution is any change across successive generations in the heritable characteristics of biological populations...

  • The Human Revolution (human origins)
    The Human Revolution (human origins)
    'The Human Revolution' is a term used by archaeologists, anthropologists and other specialists in human origins; it refers to the spectacular and relatively sudden – apparently revolutionary – emergence of language, consciousness and culture in our species...

  • Human evolution (origins of society and culture)
    Human evolution (origins of society and culture)
    While for many specialists, the term 'human evolution' should be restricted to the physical emergence of Homo sapiens as a distinct species, others – notably Chris Stringer and Stephen Oppenheimer – argue that associated cognitive, social and cultural developments are equally legitimate topics of...

  • Timeline of historic inventions

Further reading

  • d’Errico, F. & Henshilwood, C.S. 2007. Additional evidence for bone technology in the southern African Middle Stone Age. Journal of Human Evolution 52:142–163.
  • Henshilwood, C.S. 2006. Modern humans and symbolic behaviour: Evidence from Blombos Cave, South Africa. In Origins (ed. G. Blundell). Cape Town: Double Storey: 78–83.
  • Henshilwood, C. S. & Marean, C. W. 2006. Remodelling the origins of modern human behaviour. In : The Prehistory of Africa: Tracing the lineage of modern man (ed. H. Soodyall). Johannesburg: Jonathan Ball Publishers: 31–46.
  • Henshilwood, C.S. & d’Errico, F. 2005. Being modern in the Middle Stone Age: Individuals and innovation. In The Individual hominid in context: Archaeological investigations of Lower and Middle Palaeolithic landscapes, locales and artefacts. (eds. C. Gamble & M. Porr).Routledge (Taylor Francis): 244–264
  • Henshilwood, C. S. 2005. Stratigraphic integrity of the Middle Stone Age levels at Blombos Cave. In From Tools to Symbols. From Early Hominids to Modern Humans. (eds. F. d’Errico & L. Backwell). Johannesburg, Witwatersrand University Press: 441–458.
  • d’Errico, F., Henshilwood, C., Vanhaeren, M., van Niekerk. K. 2005. Nassarius kraussianus shell beads from Blombos Cave: Evidence for symbolic behaviour in the Middle Stone Age. Journal of Human Evolution 48:3–24.
  • Henshilwood, C.S. 2004. The Origins of Modern Human Behaviour: Exploring the African evidence. In Combining the Past and the Present: Archaeological perspectives on society. (eds. T. Oestigaard, N. Anfinset and T. Saetersdal). BAR International Series 1210: 95–106.
  • Henshilwood, C.S., d’Errico, F., Vanhaeren, M., van Niekerk, K., Jacobs, Z. 2004. Middle Stone Age shell beads from South Africa. Science, 384:404.
  • Henshilwood, C.S. & Marean, C.W. 2003. The origin of modern human behaviour: A review and critique of models and test implications. Current Anthropology 44 (5): 627–651
  • d’Errico F., Henshilwood C., Lawson G., Vanhaeren M., Soressi M., Bresson F., Tillier A.M., Maureille B., Nowell A., Backwell L., Lakarra J.A., Julien M. 2003. The search for the origin of symbolism, music and language: a multidisciplinary endeavour. Journal of World Prehistory, 17 (1): 1–70.
  • Henshilwood, C.S., d’Errico, F., Yates, R., Jacobs, Z., Tribolo, C., Duller, G.A.T., Mercier N., Sealy, J.C., Valladas, H., Watts, I. & Wintle, A.G. 2002. Emergence of Modern Human Behaviour: Middle Stone Age engravings from South Africa. Science 295:1278–1280.
  • Grine, F.E. & Henshilwood, C.S. 2002. Additional Human Remains from Blombos Cave, South Africa: (1999–2000 excavations). Journal of Human Evolution 42: 293–302.
  • Henshilwood, C.S., Sealy, J.C., Yates, R.J., Cruz-Uribe, K., Goldberg, P., Grine, F.E., , Klein, R.G., Poggenpoel, C., van Niekerk, K.L., Watts, I. 2001a. Blombos Cave, southern Cape, South Africa: Preliminary report on the 1992 – 1999 excavations of the Middle Stone Age levels. Journal of Archaeological Science 28(5): 421–448.
  • Henshilwood, C.S., d’Errico, F.E., Marean, C.W., Milo, R.G., Yates, R. 2001b. An early bone tool industry from the Middle Stone Age at Blombos Cave, South Africa: implications for the origins of modern human behaviour, symbolism and language. Journal of Human Evolution 41:631–678.
  • d’Errico, F., Henshilwood, C.S., & Nilssen, P. 2001. An engraved bone fragment from ca. 75 kyr Middle Stone Age levels at Blombos Cave, South Africa: implications for the origin of symbolism . Antiquity. 75, 309–18.
  • Grine, F.E., Henshilwood, C.S. & Sealy, J.C. 2000. Human remains from Blombos Cave, South Africa: (1997–1998 excavations). Journal of Human Evolution, 37: 755–765.
  • Henshilwood, C.S. 1997 Identifying the collector: Evidence for human consumption of the Cape dune mole-rat, Bathyergus suillus, from Blombos Cave, southern Cape, South Africa. Journal of Archaeological Science 24:659–662.
  • Henshilwood, C.S. & Sealy, J.C. 1997. Bone artefacts from the Middle Stone Age at Blombos Cave, southern Cape, South Africa. Current Anthropology 38(5):890–895.
  • Henshilwood, C. S. 1996. A revised chronology for the arrival of pastoralism in southernmost Africa: new evidence of sheep at ca. 2000 b.p. from Blombos Cave, South Africa. Antiquity 70:945–949.


Dating the Blombos deposits
  • Jacobs, Z. Duller, G.A.T. Henshilwood, C.S. Wintle, A.G. 2006. Extending the chronology of deposits at Blombos Cave, South Africa, back to 140 ka using optical dating of single and multiple grains of quartz. Journal of Human Evolution 51: 255–273.
  • Tribolo, C., Mercier, N., Selo, M., Joron, J-L., Reyss, J-L., Henshilwood, C., Sealy, J. & Yates, R. 2006. TL dating of burnt lithics from Blombos Cave (South Africa): further evidence for the antiquity of modern human behaviour. Archaeometry, 48 (2): 341–357.
  • Jacobs, Z. Duller, G.A.T., Wintle, A.G. & Henshilwood, C.S. 2006.Extending the chronology of deposits at Blombos Cave, South Africa, back to 140 ka using optical dating of single and multiple grains of quartz. Journal of Human Evolution 51: 255–273.
  • Jacobs, Z., Wintle, A. G. & Duller, G. A. T. (2003a). Optical dating of dune sand from Blombos Cave, South Africa: I—multiple grain data. J. Hum. Evol. 44, 599 – 612.
  • Jacobs, Z., Duller, G. A. T. & Wintle, A. G. (2003b). Optical dating of dune sand from Blombos Cave, South Africa: II—single grain data. J. Hum. Evol. 44, 613 – 625.


External links

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