radiometric age determinations for early hominids and for the preagricultural stone age in africa

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Board of Trustees, Boston University Radiometric Age Determinations for Early Hominids and for the Preagricultural Stone Age in Africa Author(s): Creighton Gabel Source: The International Journal of African Historical Studies, Vol. 5, No. 1 (1972), pp. 1-21 Published by: Boston University African Studies Center Stable URL: http://www.jstor.org/stable/216798 . Accessed: 09/05/2014 15:33 Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at . http://www.jstor.org/page/info/about/policies/terms.jsp . JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact [email protected]. . Boston University African Studies Center and Board of Trustees, Boston University are collaborating with JSTOR to digitize, preserve and extend access to The International Journal of African Historical Studies. http://www.jstor.org This content downloaded from 169.229.32.138 on Fri, 9 May 2014 15:33:14 PM All use subject to JSTOR Terms and Conditions

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Board of Trustees, Boston University

Radiometric Age Determinations for Early Hominids and for the Preagricultural Stone Age inAfricaAuthor(s): Creighton GabelSource: The International Journal of African Historical Studies, Vol. 5, No. 1 (1972), pp. 1-21Published by: Boston University African Studies CenterStable URL: http://www.jstor.org/stable/216798 .

Accessed: 09/05/2014 15:33

Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at .http://www.jstor.org/page/info/about/policies/terms.jsp

.JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range ofcontent in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new formsof scholarship. For more information about JSTOR, please contact [email protected].

.

Boston University African Studies Center and Board of Trustees, Boston University are collaborating withJSTOR to digitize, preserve and extend access to The International Journal of African Historical Studies.

http://www.jstor.org

This content downloaded from 169.229.32.138 on Fri, 9 May 2014 15:33:14 PMAll use subject to JSTOR Terms and Conditions

RADIOMETRIC AGE DETERMINATIONS FOR

EARLY HOMINIDS AND FOR THE

PREAGRICULTURAL STONE AGE IN AFRICA

Creighton Gabel

During the past decade or so, there has been a rapid and very substantial increase in the number of isotopic dates for the African Late Tertiary and Quaternary which has, among other things, served to, raise the apparent age of man on the continent to something on the order of 3.75 million years. Whether relating to earliest man or not, these new dates have an obvious value in providing a more realistic perspective of the entire pan- orama of human biological and cultural evolution. With these "absolute" chronological guidelines, it should prove possible to align local archae- ological, geological, faunal, and botanical sequences and ultimately to correlate them across Africa and beyond. The general rejection of previ- ously devised climatic ("pluvial") chronologies for Africa,' at least as applied on a wide scale, makes the need for such dates all the more acute.

The isotopic dating methods currently of primary importance in paleo- anthropological studies are potassium-argon (K/Ar) and radiocarbon (C-14). Each involves different types of samples and, thus far, mutually exclusive portions of the total time spectrum. K/Ar analysis, baseld on measuring the rate of decay of potassium-40 to argon-40, requires potas- sium-rich mineral samples such as one finds in certain areas of past vol- canic activity. The tectonically disturbed regions of eastern Africa, which are presently producing the greatest number of new early hominid finds, are ideal for its application.2 Acceptable, or seemingly acceptable, K/Ar dates in Africa all relate to materials a million or more years of age; a few more recent dates have been obtained but are suspect on grounds of pos-

1 For a history of this, see W. W. Bishop, "Annotated Lexicon of Quaternary Strati- graphical Nomenclature in East Africa," in W. W. Bishop and J. D. Clark, eds., Back- ground to Evolution in Africa (Chicagoi, 1967), 375-395.

2 Unfortunately, this is not true of the Transvaal Australopithecine sites, which are still dated on paleontological grounds alone.

The International Journal of African Historical Studies, v, 1 (1972)

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2 CREIGHTON GABEL

SUDAN

Lothagam

. Kanapoi UGANDA

KENYA

* Baringo

* Ft. Ternar

Penin j

TANZANIA

Late Miocene - Early Pleistocene localities mentioned in the text

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RADIOMETRIC AGE DETERMINATIONS

sible contamination or disagreement with other available evidence. Occa- sionally, it has proved feasible to check the accuracy of K/Ar results by means of fission-track dating (counting the number of microscopic tracks, or etchings, resulting from the spontaneous fission of uranium-238 in vol- canic glasses or crystals) or by correlation with evidence of reversed paleo- magnetic polarity (periodic reversals of the earth's magnetic field from north to south revealed by the orientation of iron and titanium oxides in volcanic rocks).

Radiocarbon analysis involves the measurement of C-14 loss in organic specimens such as bone, wood, or charcoal. It is applicable anywhere that a suitable quantity of such material is found within a timespan of approxi- mately the past fifty thousand to sixty thousand years.3

Barring further refinement of these methods, or the introduction of new

techniques of dating, there is therefore a chronological hiatus of a million years or more within the Pleistocene for which we have few or no accept- able dates. Within this period (roughly 60,000 to ?-1.0 million years ago), we are still essentially dependent on the relative dating evidence provided by geology and paleontology.

Application of K/Ar Dating in Late Tertiary and Early Pleistocene Deposits

Included in this section are localities of Miocene, Pliocene, or Early Pleistocene age which, with one exception, incorporate fossils of hominid or hominid-related character. A few also include stone implements, pre- dominantly of Oldowan ("pebble tool") type.

Because of unresolved controversies regarding the status of L. S. B. Leakey's Homo habilis and the inability of paleontologists to determine the precise taxonomic status of certain fragmentary specimens, no effort has been made here to do more than simply list the hominid designations suggested by individual investigators in their publications. It will be noted that some degree of contemporaneity is intimated at a few localities be- tween either Australopithecus africanus / Australopithecus robustus or Australopithecus robustus / Homo (habilis or unspecified).

One major contribution of K/Ar dating has been to contradict the

belief, widely held until very recently, that geological and paleontological deposits of Pliocene age in Africa are almost universally lacking. The new dates from Omo, Ileret and Koobi Fora, Kanapoi, Lothagam, and Fort

3 A newer method, utilizing carbons incorporated in iron objects at the time of smelt-

ing, shows some promise for dating at Iron Age horizons. See N. J. van der Merwe and M. Stuiver, "Dating Iron by the Carbon-14 Method," Current Anthropology, IX (1968), 48-53.

3

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4 CREIGHTON GABEL

Ternan illustrate the fact that the presumed gap is not only being closed but that some of the earliest hominids of Australopithecine type may be of late Pliocene date.4

Perhaps most obvious, and in some ways more important, is the enor- mously increased timespan which must now be envisioned for the evolu- tionary and cultural development of early man.

A representative group of dated deposits includes: 1. Rusinga Island, Lake Victoria, Kenya. Type-locality for Proconsul

africanus;5a Miocene primate possibly ancestral to later African apes and/or man. The most recent K/Ar and stratigraphic assessment of age is -- 18 million years.6

2. Fort Ternan, Western Kenya. African type-locality for Ramapithe- cus (or, in Leakey's terms, Kenyapithecus africanus), a primate fossil known previously from India, which may have been a pre- Australopithecine hominid. Some evidence is present of rocks be-

ing used to crush the skulls and bones of other animals, according to Leakey.7 There is a K/Ar date of +- 14.0 million years, but the actual age may be somewhat less - possibly early Pliocene rather than late Miocene.8

3. Ngorora, Lake Baringo, Kenya.9 Early Pliocene formation with frag- ments of possible Ramapithecus. K/Ar dates suggest an age be- tween 9.0 and 12.0 million years.

4. Lothagam, Northern Kenya."0 Pliocene deposits just west of Lake Rudolf with a minimum K/Ar age of ?3.7 million years and an estimated age of -?5.5 million which may fall between Ngorora and Omo. No hominid fossils have been reported thus far.

5. Omo, Southern Ethiopia.11 Late Pliocene/Early Pleistocene riverine and delta sediments covering a timespan of about 1.6-4.5 million

4K. P. Oakley, "Pliocene Men," Antiquity, XLIV (1970), 307-308. 5 L. S. B. Leakey, "Skull of Proconsul from Rusinga Island," Nature, CXLII (1948),

688. 6 J. A. Van Couvering and J. A. Miller, "Miocene Stratigraphy and Age Determina-

tions, Rusinga Island, Kenya," Nature, CCXXI (1969), 628-632. 7 L. S. B. Leakey, "Lower Dentition of Kenyapithecus Africanus," Nature, CCXVII

(1968), 827-830. 8 W. W. Bishop, "The Later Tertiary in East Africa - Volcanics, Sediments, and

Faunal Inventory," in W. W. Bishop and J. D. Clark, eds., Background to Evolution in Africa (Chicago, 1967), 41.

9 W. W. Bishop and G. R. Chapman, "Early Pliocene Sediments and Fossils from the Northern Kenya Rift Valley," Nature, CCXXVI (1970), 914-918.

10 B. Patterson, A. Behrensmeyer, and W. Sill, "Geology and Fauna of a New Plio. cene Locality in Northwestern Kenya," Nature, CCXXVI (1970), 918-921.

11 F. C. Howell, "Omo Research Expedition," Nature, CCXIX (1968), 567-572; F. H. Brown and K. R. Lajoie, "Radiometric Age Determinations on Pliocene/Pleistocene

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RADJOMETRIC AGE DETERMINATIONS 5

years. Fifty-one hominid localities were recorded by late 1970, in- cluding one partial skull, six partial or complete jaws, and over 100 teeth. These specimens have been referred to Australopithecus ro- bustus or boisei and to Australopithecus africanus, both of which occur on some individual sites as far back as at least 3.0 million years. Altogether, hominid remains have been found in, strata dating from 1.93-3.75 million years. Worked bone and worked stone have been, reported from exposed surfaces, and it is anticipated that they will be found in sealed contexts eventually.

6. Kanapoi, Northern Kenya.12 Deposits southwest of Lake Rudolf dated at 2.5-2.9 million years which include one limb fragment of a possible Australopithecine (Aus. sp.). No artifacts have been re- covered. Because of conflicts in faunal and K/Ar evidence, it is

suggested that a date more like 4.0-4.5 million years would be more reasonable (or about the same as the oldest Omo deposits).

7. Koobi Fora and Ileret, Northern Kenya.1 Newly investigated fossil beds just south of the Ethiopian border on the eastern side of Lake Rudolf. The initial work produced Oldowan artifacts dated provi- sionally by K/Ar at 2.61 million years and 23 hominid specimens (complete cranium, seven partial crania and fragments, one com-

plete jaw, eight partial jaws and fragments, and six limb fragments). Nineteen are referred to Australopithecus (at least partly of the more robust variety) and Homo (sp.). If the date is correct, it im-

plies that tool-making hominids were present in eastern Africa be- fore the end of the Pliocene.T4 Although perhaps 800,000 years older, the Oldowan implements collected here are described as being better made than those in Bed I, Olduvai Gorge - the type- locality for the industry.

8. Bed I, Olduvai Gorge, Northern Tanzania.5 Early Pleistocene de-

Formations in the Lower Omo Basin, Ethiopia," Nature, CCXXIX (1971), 483-485; K. Butzer, "The Lower Omo Basin: Geology, Fauna, and Hominids," Naturwissenschaf- ten, LVIII (1971), 7-16.

12 B. Patterson, "A New Locality for Early Pleistocene Fossils in Northwestern Kenya," Nature, CCXII (1966), 577-578; B. Patterson and W. W. Howells, "Hominid Humeral Fragment from Early Pleistocene of Northwestern Kenya," Science, CLVI (1967), 64-66.

13 R. Leakey, "New Hominid Remains and Early Artifacts from Northern Kenya," Nature, CCXXVI (1970), 223-230; R. Leakey, "Further Evidence of Lower Pleistocene Hominids from East Rudolf, Kenya," Nature, CCXXXI (1971), 241-245; G. Isaac, R. Leakey, and A. Behrensmeyer, "Archaeological Traces of Early Hominid Activities, East of Lake Rudolf, Kenya," Science, CLXXIII (1971), 1129-1134.

14 Current estimations of the age of the Pliocene/Pleistocene boundary range from 2.0 to 2.7 million years.

15 L. S. B. Leakey, Olduvai Gorge 1951-1961 (Cambridge, 1965); P. V. Tobias, "New

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6 CREIGHTON GABEL

posits of volcanic and fluvial/lacustrine origin containing Oldowan

living floors and an abundant fauna. Hominid remains include eight individuals: one skull of Australopithecus robustus or boisei ("Zin-

janthropus"), a fairly complete new skull assigned to Homo habi- lis,16 and assorted teeth, cranial, mandibular, hand, foot, and limb

fragments referred primarily to Homo habilis. K/Ar dates range from about 1.57 to 1.91 million years, averaging about 1.8 million. These are essentially confirmed by a fission-track date of 2.03 mil- lion17 and evidence of a normal magnetic polarity event which is known to have occurred outside Africa also at about 1.8 million.'8

K/Ar dates of 1.0 million for the top of Bed I and of 0.5 million for upper Bed II (where a skullcap of Homo erectus was found) have been generally rejected.19

9. Chesowanja, Baringo District, Kenya.20 Deposits containing fauna similar to that of Olduvai Bed II and Peninj dated 1.1-1.2 million

years by potassium-argon. The facial skeleton of an adult Australo-

pithecus robustus was found with faunal and plant remains sugges- tive of a lagoon-side environment.

10. Peninj, Lake Natron, Northern Tanzania.2" Humbu Formation with fauna similar to that of upper Bed II at Olduvai and including an

Australopithecus robustus mandible. Lower Acheulian artifacts have been recovered slightly higher in the same formation but cannot be

definitely assigned to Australopithecus robustus. Immediately under-

lying the Humbu Formation - and presumably not much earlier- is a lava bed representing the last reversal of the earth's magnetic field, which is dated elsewhere at about 0.7 million years.

Discoveries in Tanganyika: Their Bearing on Hominid Evolution," Current Anthropol- ogy, VII (1965), 391-411.

16 M. Leakey, R. J. Clarke, and L. S. B. Leakey, "New Hominid Skull from Bed I, Olduvai Gorge, Tanzania," Nature, CCXXXII (1971), 308-312.

17 J. Evernden and G. Curtis, "The Potassium-Argon Dating of Late Cenozoic Rocks in East Africa and Italy," Current Anthropology, VI (1965), 351-355; R. L. Fleischer, L. S. B. Leakey, P. B. Price, and R. M. Walker, "Fission Track Dating of Bed I, Olduvai

Gorge," Science, CXLVIII (1965), 72-74. 18 A. Cox, G. Dalrymple, and R. Doell, "Reversals of the Earth's Magnetic Field,"

Scientific American, CCXVI, 2 (1967), 44-54. 19 G. Isaac, "Studies of Early Culture in East Africa," World Archaeology, I (1969), 5. 20 J. Carney, A. Hill, J. Miller, and A. Walker, "Late. Australopithecine from Baringo

District, Kenya," Nature, CCXXX (1971), 509-514. 21 G. Isaac, "The Stratigraphy of the Peninj Beds and the Provenance of the Natron

Australopithecine Mandible," Quaternaria, VII (1965), 101-130; G. Isaac, "Studies of

Early Culture," 3.

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RADIOMETRIC AGE DETERMINATIONS

Geophysical Dates for Key Miocene, Pliocene, and Early Pleistocene Locations in Eastern Africa.

Locality Age Fossils Tools

Peninj 0.7 million Aus. rob.

Chesowanja 1.1-1.2 million Aus. rob. Olduvai Bed I 1.8 million Aus. rob., Oldowan

H. habilis Koobi Fora & 2.61 million Aus. (?rob.), Oldowan

Ileret Homo sp. Kanapoi 2.5-2.9 million Aus. sp.

(or older) Omo 1.93-3.75 million Aus. rob., Oldowan?

Auss. afr. Lothagam 3.7 million --

or more

Ngorora 9.0-12.0 million ?Ramapithecus Fort Ternan 14.0 million Ramapithecus ?

Rusinga Island 18.0 million Proconsul afr.

Radiocarbon Dates for Late Pleistocene and Early Holocene Stone Industries

Since 1950, radiocarbon dating has provided the means for establishing independent and cross-referable chronotloges for the later phases of pre-

history in most parts of the world. In the accumulation of dates required for building up regional time scales, Africa lagged well behind Europe and the Americas for at least a decade. In 1959, at the Fourth Pan-African

Congress on Prehistory, a summary paper by J. D. Clark22 on the implica- tions of C-14 dating for sub-Saharan Africa was formulated on the basis of less than fifty dates pertaining to fifteen widely scattered sites or local- ities. The reasons for this lag were presumably the relatively small amount of archaeological fieldwork 'carried out up to that time and the lack of access to the few existing radiocarbon laboratories outside the continent. A marked increase in prehistoric research and the opening of new labora- tories, including four or five in Africa itself, have altered the picture con-

22 J. D. Clark, "Carbon 14 Chronology in Africa South of the Sahara," in G. Mortel- mans and J. Nenquin, eds., Actes du IVe congres panafricain de Prehistoire et de l'Etude du Quaternaire (Tervuren, 1962), 303-314.

7

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8 CREIGHTON GABEL

siderably. There are now more than one thousand published dates relating to about four hundred archaeological sites in thirty countries.23

It has been recognized for some time that temporal (although appar- ently not geographical) variations in the amount of atmospheric carbon- 14 require us to distinguish between radiocarbon age and true age.24 Only slight deviations seem to have occurred during the last 2000 years, but these then increase steadily until about 4000-5000 B.C., when 800 to 900 years have to be added to obtain a true age. Between 5000 B.C. and the end of the Pleistocene, radiocarbon ages may more nearly coincide with true age, but there is little confirming evidence. The magnitude of such deviations during the Pleistocene is not yet known, although their relative significance might be less in terms of the greater time range involved. In any case, the assessment of comparative age of different sites should not be affected, assuming geographic constancy of atmospheric C-14 at any given point in time.

One of the primary concerns of archaeologists working in Africa at the

present is to reevaluate and redefine the stone industries of the continent on a more scientifically precise basis.25 Eventually, many of the existing classificatory designations, both general and specific, are likely to be aban- doned, replaced, or modified in order to gain greater terminological preci- sion and to enhance the possibilities of cross-comparisons; At least for those portions of the Stone Age falling within the Late Pleistocene and post-Pleistocene, radiocarbon dating is making the need for such reassess- ments even more acutely felt since it frequently has tended to contradict the notion of uniform and discrete developmental stages in, stoneworking technology. Some assemblages regarded as essentially identical have proved to be quite disparate in age, while others once regarded as sequential seem to overlap extensively.

In the following summary of dates available for the Late, Pleistocene and early Holocene, all ages are given in years B.C., using the conventional method of subtracting 1,950 years from the radiocarbon date reported (thus a date of 15,500 years is recorded as 13,550 B.C.). Most radiocarbon dates are expressed as averages together with a standard deviation reflect-

23 Archaeological dates cited herein have been drawn from some general sources (A. Jelinek, "An Index of Radiocarbon Dates Associated with Cultural Materials," Current Anthropology, III [1962], 451-477; J. Deacon, "An Annotated List of Radiocarbon Dates for Sub-Saharan Africa," Annals of the Cape Provincial Museums, V [1966], 5-84; Radiocarbon, I-XIII [1959-19711) as well as from numbers of individual site reports.

24 See E. Neustupny, "A New Epoch in Radiocarbon Dating," Antiquity, XLIV

(1970), 38-45, with references. 25 W. W. Bishop and J. D. Clark, eds., Background to Evolution in Africa (Chicago,

1967), 879-901.

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RADIOMETRIC AGE DETERMINATIONS

ing the most likely age; for example, in a sample dated 15,000 +500 years there is a 68% chance that the true radiocarbon age lies between 14,500 and 15,500 years. For the sake of simplicity, plus-and-minus fac- tors have been ignored here. In most instances, the possible error intro- duced by their exclusion is minimal since the majority of standard devia- tions are relatively small in comparison with the indicated average age of

samples under consideration. No isotopic dates of any kind are available for the bulk of the Acheulian

(handaxe) industrial complex, which may have begun a million or more

years ago. Late occurrences of Upper Acheulian have been dated at Ka- lambo Falls in northern Zambia (several results suggesting a probable age of about 58,000 B.C.) and at Amanzi Spring in the Cape (three dates

ranging from about 31,000 to 58,650 B.C.). These are taken to be about the most recent dates possible for such material.

North African Mousterian, or Levalloiso-Mousterian, stone industries, similar to those of the same name in Europe and southwest Asia, have been dated at Haua Fteah Cave in Cyrenaican Libya (four dates ranging from about 32,050 to 45,050 B.C., the last associated with a Neanderthaloid mandible), Jebel Irhoud in Morocco (>30,050 B.C.,26 associated with the remains of two Neanderthaloid individuals), and Dungal Oasis in

Egypt (geological marker bed containing Mousterian tools, 20,950 B.C.). The last of these seems substantially younger than one would anticipate.

Sangoan industries, which feature large picks, core axes, and scraping tools as well as implements of smaller size, appear to have been early Upper Pleistocene derivatives of the Acheulian. They are widely distrib- uted in the central portions of the continent, with outliers in the Sudan, the Guinea coast, and southern Africa. Believed to represent the first major adaptation to humid forest or forest-and-savannah mosaic, they may reflect

greater use of vegetable foods and increased reliance on wood as a raw material. At Kalambo Falls, where Sangoan occurrences overlie Acheulian

ones, there is a series of about a dozen dates (35,500 to 44,150 B.C.) which imply approximate contemporaneity with the North African Mous- terian. A single date of >40,050 B.C. for the Sangoan level at Pomongwe Cave in Rhodesia was based on a sample too small for an accurate count, but the same site produced dates of 33,550 and 40,300 B.C. for a horizon

yielding "Proto-Stillbay" ("Charaman") materials which many authorities now regard as a Sangoan phase in south central Africa.27 A similar occur-

26 Dates such as this ("more than") usually reflect samples too old or too small for an accurate count.

27 C. K. Cooke, R. Summers, and K. R. Robinson, "Rhodesian Prehistory Re-examined, Part I: The Stone Age," Arnoldia, XII (1966), 4.

9

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10 CREIGHTON GABEL

rence at the Twin Rivers site in Zambia has dates of 20,850 and > 31,250 B.C. It was with such an industrial variant that theNteanderthaloid Broken Hill skull was found fifty years ago in the same general area.

During the later part of the Upper Pleistocene, local variability in stone- working technology became more pronounced, a trend continued and elab- orated in the early Holocene. One finds a basic differentiation, although not necessarily a rigid one geographically or technologically, between assemblages featuring either continued use of a substantial proportion of heavier tools, emphasis on the Levallois technique together with the use of smaller core and flake implements, or a high index of blade tools. These are succeeded by, or quite early begin to incorporate, assemblages with greater microlithic content. It is not always clear in the case of blade or microlithic elements what relationships existed with Europe or the Levant

(although, on the whole, one sees more resemblances to those areas in northern Africa), but previous assumptions that these were simply intro- duced wholesale into Africa from external sources are not being borne out by radiocarbon evidence. Blade industries in at least one instance seem to have appeared as early as any found elsewhere, and microlithic ones in a number of areas have yielded astonishingly early dates.

Apparently Mousterian-derived, the North African Aterian, with its characteristic tanged projectile points, displays some resemblances to, Still- bay-type industries of eastern and southern Africa. It occurs from Morocco as far east as the Kharga Oasis in Egypt and into the Sahara as far south as Chad. Dated occurrences include Dar-es-Soltan, Morocco (>25,050 and >28,050 B.C.), Fachi, eastern Niger (17,500 and 19,350 B.C.), Wadi Gan, Libya (4,550 B.C.), and Djebbana, Algeria (1,950 B.C.). The last two dates might be discounted at first glance, and perhaps should be, although some isolated populations may have continued the tradition as an Aterien preneollithique.28

The Dabban blade industry of Cyrenaica is the earliest one of its kind known thus far in Africa. Chronological evidence from Haua Fteah Cave (14,120 to 31,150 B.C.) and Ed Dabba Cave (>37,550 and 38,550 B.C.) implies a very long timespan as well as a remarkably early origin.

A later blade industry, the Oranian, occurs in both Cyrenaica and the

Maghreb during the terminal Pleistocene. In contrast with the Dabban, there is thought to be somewhat more indication of outside (southwest Asian?) influence, although this is far from proven. Existing C-14 dates

range from about 8,000 to 12,500 B.C. (Taforalt, Morocco, 8,550 to

28 H. J. Hugot, "Le Paleolithique terminal dans I'Afrique de l'ouest," in W. W.

Bishop and J. D. Clark, eds., Background to Evolution in Africa (Chicago, 1967), 441.

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RADIOMETRIC AGE DETERMINATIONS

1.1,050 B.C..; Rassel, Algeria, 12,320 B.C.; Tamer Hat, Algeria, 8,400 and 10,500 B.C.; Haua Fteah Cave, Cyrenaica, 8,650 to 10,800 B.C.).

Once thought to substantially overlap the Oranian, the Capsian blade- and-microlithic complex (usually occurring in enormous snail shell mid- dens which seems to indicate dependence on this organism as a food staple) has now been placed quite convincingly in the early Holocene. Dated occurrences, excluding the so-called "Neolithic of Capsian Tradition," fall within a period of roughly 3,000 to 7,000 B.C. Tunisian sites include Gafsa (6,650 B.C.) and Bortal Fakher (4,950 and 5,750 B.C.), while Algerian ones are Ain Boucherit (3,170 to, 5,050 B.C.), El Marmouta (4,290 and 4,500 B.C.), Medjez 11 (4,550 to 5,910 B.C.), Khanguet-el- Mouhaad (5,250 B.C.), el-Abiod (5,250 B.C.), R'Fana (5,500 B.C.), Ain Naga (5,270 to 7,350 B.C.), Koudiat Kifen Lahda I (6,100 B.C.), and Columnata (4,390 and 4,900 B.C.). Between Capsian and Oranian levels at the Columnata site is an ultramicrolithic assemblage dated at 4,850 to 6,330 B.C., and a similar "Columnatian" occurrence dated at 6,370 B.C. underlies the normal Capsian at Koudiat Kifen Lahda I. The "Libyco-Capsian" at Haua Fteah Cave is dated between 5,350 and 6,450 B.C.

As the result of archaeological reconnaissance and excavation carried out in conjunction with the Aswan salvage program, a whole new series of .Late Pleistocene and early Holocene stone industries has emerged in Nubia.29

In the Wadi Halfa region, the Khormusan industry occurs in what

appear to be overlapping campsites along the river. Predominantly in the flake-tool category, it incorporates a high percentage of unretouched Levallois flakes, burins, and denticulated pieces. Although lacking bifacial artifacts, the industry bears some resemblance to the East African "Still-

bay." Two sites are dated at 15,850 and 20,750 B.C. respectively. First identified nearly fifty years ago, the Sebilian is concentrated around

the Kom Ombo area of Upper Egypt, with extensions down to Wadi Halfa. Its several stages (beginning as a flake industry and culminating in a blade-and-microlithic industry) seem to fall between about 9,000 and 13,000 B.C. (Gebel Silsila, Kom Ombo, Egypt: 11,120-13,360 B.C.; New Abu Simbel, Egypt: 10,070 B.C.; Khor Musa, Sudan: 8,975 and 9,050 B.C.).

The Sebekian and Silsilian of Kom Ombo are quite like the Oranian and may be related in some degree.30 The former is characterized by long,

29 See especially F. Wendorf, ed., The Prehistory of Nubia (Dallas, 1968). 30 p. E. L. Smith, "The Late Paleolithic of Northeast Africa in the Light of Recent

Research," American Anthropologist, LXVIII (1966), 343.

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12 CREIGHTON GABEL

narrow, retouched blades, while the latter is much more microlithic and includes backed bladelets, microburins, and some geometric pieces. Five Sebekian dates at Gebel Silsila range from 11,660 to 14,050 B.C. Although not dated by C-14, the Silsilian underlies the Sebekian at Gebel Silsila.

At El Kilh, between Kom Ombo. and Luxor, a flake-and-blade& industry thus far identified only as "Complex A" has five radiocarbon dates cluster-

ing closely between 15,000 and 15,850 B.C. "Complex B" at Esna in the same region, which has higher percentages of both microlithic and flake

tools, appears to be of about the same age ( 15,640 and 16,070 B.C.). A number of other lithic complexes, probably falling between around 10,000 and 15,000 B.C., have been recognized in the area but are not yet very securely dated other than geologically.31

The Ballanan blade industry of Wadi Halfa, which has a marked micro- lithic aspect, is placed by a single date at 12,050 B.C. Even earlier there is the Halfan, with a large proportion of microlithic flake tools. Three sites are dated at 14,550, 16,650, and 17,200 B.C. The Qadan microlithic flake- and-blade industry at Wadi Halfa appears to be primarily terminal Pleis- tocene but may have persisted into the Holocene (four sites dated at 4,480, 9,250, 9,460, 12,550 B.C.). In one instance, the Qadan may be associated with a cemetery whose occupants display an amazingly large number of violence-incurred wounds.32

Largely or entirely post-Pleistocene microlithic industries in Nubia are the preceramic Arkinian (7,440 B.C.) and Shamarkian (3,270, 3,650, and 5,750 B.C.). A possible Qadan derivative which is rather less micro- lithic and includes plain pottery is the Abkan (2,520, 2,550, 4,010 B.C.). At El Kab in Egypt, a microlithic blade industry with one date of 6,400 B.C. succeeds the local Upper Sebilian.

In northern Egypt, small fishing camps which seem to belong to G.

Caton-Thompson and E. W. Gardner's Fayum, B33 have been placed at about 5,190-6,150 B.C. These contain blade and microlithic implements as well as some grindstones and barbed bone points (but not the pottery, bifacial tools, and arrowheads described by the original investigators). Also, it is clear that the Fayum B material antedates, not follows, the Neolithic Fayum A occurrences of ?4000 B.C.

In view of the early dates for the Dabban industry in Cyrenaica, the Nubian blade-tool traditions are more noteworthy for their diversity and

31 F. Wendorf, R. Said, and R. Schild, "Egyptian Prehistory: Some New Concepts," Science, CLXIX (1970), 1164-1165.

32 F. Wendorf, "A Nubian Final Paleolirhic Graveyard near Jebel Sahaba, Sudan," in F. Wendorf, ed., The Prehistory of Nubia (Dallas, 1968), 954-995.

33 G. Caton-Thompson and E. W. Gardner, The Desert Fayum (London, 1934).

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RADIOMETRIC AGE DETERMINATIONS

their presence in an area previously regarded as something of a cultural vacuum than for their antiquity. Most remarkable are the microlithic

expressions, which in a number of instances are much older than one would have anticipated. Together, the Nubian blade and microlithic indus- tries have diminished the gap between the Mediterranean and East Africa, where some technologically comparable materials are found. Unfortu- nately, we have no dates for the Hargeisan blade industry in the Horn and but two for the Kenya Capsian.

Although very similar to the Maghrebian Capsian, the Kenya Capsian seems to have begun earlier. Just as with its northwest African namesake, its stoneworking traditions were continued by some of the first pastoral populations - in this; case the Stone Bowl cultures of the Rift Valley. It is tempting to speculate that the Kenya Capsian heralds the arrival of

Cushitic-speaking peoples in the area, but supporting glottochronoilogical evidence is meager because of the time depth involved.34 Two' sites near Elmenteita have been dated in the terminal Pleistocene, Prospect Farm

(8,610 B.C.) and Enderit Drift ( 10,350 B.C.). The Sangoan-derived Lupemban industrial complex (or the Upper

Sangoan, Djokocian, or Kalinian of some earlier investigators) is charac- terized by well-made bifacial axes, adzes, gouges, and elongated "lance- heads." Not as widespread as the more generalized Sangoan, the Lupemban is limited essentially to the Congo basin and immediately adjacent areas. Radiocarbon results suggest a long timespan and, therefore, possibly some

overlap with the Sangoan proper. Dated sites in the Kinshasa region in- clude Basoko River (10,280, >24,050, >28,050 B.C.), Cabu (13,130 B.C.), and Lemba (>28,050 B.C.). At Mufo Mine in northeastern An-

gola, there are dates of 12,553, >32,050, and 36,050 B.C. The Kalambo Falls variant (overlying Sangoan) falls at 27,050-29,710 B.C.

A Lupemban offshoot known as the Tshitolian occurs in the Congo basin and northeastern Angola, where it likewise appears to have had a

long duration. Small woodworking tools are frequently accompanied by either microlithic transverse projectile points or small leaf-shaped or

tanged points. It is conceivable that industries of this kind were produced by Pygmoid populations, as Murdock suggests for the Sangoan as a whole,35 but there is no proof of it thus far. Intermediate "Lupembo-Tshitolian" or "Lower Tshitolian" dates from Angola indicate origins in the terminal Pleistocene (9,239 B.C. at Mufo Mine and 11,020 B.C. at Calunda 3 Mine). Later Tshitolian dates at the' same sites are 4,880 and 2,750 B.C.

34 Harold Fleming, personal communication. 35 G. P. Murdock, Africa: Its Peoples and Their Culture History (New York, 1959),

48.

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14 CREIGHTON GABEL

respectively. At Furi I Mine in Angola, a late Tshitolian with possibly intrusive pottery has a date of A.D. 150, and Tshitolian with pottery at Murrhura overlies a buried landsurface dated at A.D. 1150. In the Kin- shasa area, other dates have been recorded: 3,800 and 4,080 B.C. at Mount Gafula, 4,330 B.C. at Kizenzu, 6,970 B.C. at Cabu, and 7,780 B.C. at Basoko. At the Cave of Bitorri, Brazzaville, a late Tshitolian occurrence has dates of 1,980 and 2,080 B.C.

Also associated with more heavily wooded country is the Nachikufan industry of northern Zambia, which incorporates geometric and non- geometric microliths, bored "kwe" stones, polished stone axes and adzes, bone points, grindstones, pestles, and pigments utilized for schematic art. Because of the emphasis on heavy woodworking tools, transverse points, grindstones, and digging stick weights, it is assumed that the Nachikufan as a whole represents adaptation to forest conditions, with extended use of wood and of vegetable foods. A four-part typological/chronological sub- division is currently recognized: Nachikufan I, IIa, IIb, and III.

Overlying a "Proto-Later Stone Age" horizon of 19,600-21,650 B.C. at

Leopard's Hill Cave is one Nachikufan I occurrence dated at 14,765 B.C. Another at Mwela Rocks is placed at 9,310 B.C. "Post-Nachikufan I" assemblages at Chifubwa Stream Shelter (4,360 B.C.) and Nachikufu Cave (7,770 B.C.) fall a bit later. Nachikufan IIa is dated about 7,750 B.C. at Leopard's Hill Cave and 5,310-6,690 at Mwela Rocks. Nachikufan IIb at Nachikufu Cave occurs between 2,880 and 3,680 B.C. Nachikufan III, which often includes pottery and/or iron, is much later: A.D. 890 and A.D. 1,750 at Nachikufu Shelter, A.D. 1,650 at Nachikufu Cave, 915 and 1,550 B.C. at Leopard's Hill Cave, and A.D. 770 and A.D. 1,040 at Nakapapula Shelter (which also yielded a date of 1,330 B.C.).

Widely distributed in the more open woodlands and savannahs of South, south central, and East Africa are Late Pleistocene industries characterized by use of the Levallois technique and featuring predominantly lightweight implements such as scrapers, cutting tools, and unifacial or bifacial pro- jectile points. Numbers of regional expressions have been subsumed under the term Stillbay, a designation almost certain to be abandoned or strin- gently redefined as more detailed typological analyses are undertaken. Similar "Middle Stone Age" materials already have been segregated as 'separate industries or special variants in southern Africa (e.g., Pietersburg, Hagenstad, Mossel Bay, Mazelspoort, Bambatan). Over one-half the avail- able C-14 dates fall between 8,000 and 35,000 B.C. A third or more - too many to be dismissed out of hand - suggest overlap with the Sangoan (35,000 to over 50,000 B.C.). A few Holocene dates may reflect either erroneous chronological results, mistaken typological assessment, or iso-

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RADIOMETRIC AGE DETERMINATIONS

lated persistence of earlier technologies. The broad range of dates, in any case, suggests that total reevaluation of the complexity in lithic sequences may be necessary in some areas (see also comments below on the "Mago- sian") :36

Cape Province: Wagenaar's Cave (nondescript "Middle Stone Age," 16,710 B.C.); Witkranz Cave (Pietersburg, 31,200 B.C.); Peer's Cave (Stillbay, 34,050, >33,650 B.C.); Melkbos ("late Middle Stone Age," 41,250B.C.); Baviaanskloof (unspecified "Middle Stone Age," 10,700B.C.).

Swaziland: Sibebe Shelter ("Middle Stone Age," 20,900 B.C.).

Orange Free State: Florisbad (Mazelspoort, Peat III, 4,750 and 17,580 B.C.; Mazelspoort, Peat II, 7,154 and 26,500 B.C.; Hagenstad, Peat I, >33,050, >39,050, >42,050, and >46,950 B.C. - associated with the Florisbad skull, which may represent an early sapient type).

Natal: Holley Shelter (unspecified "Middle Stone Age," 2,540 an( 16,250 B.C.).

Transvaal: Cave of Hearths37 (Pietersburg, 9,650, 9,750, 13,150, ani 14,861 B.C.); Olieboompoort Cave (Pietersburg, >23,050 B.C.); Bush- man Rock (unspecified "Middle Stone Age," 10,520, >43,550, >49,050 B.C. - first date may represent intrusion of a sample from overlying "Later Stone Age" level).

Rhodesia: Pomongwe Cave (Stillbay [Bambatan], 19,750 B.C.); Redcliff (Stillbay [Bambatan], 33,550, 38,920, 39,850 and >37,950 B.C.).

It is widely suspected that the so,-called "Magosian" occurrences of eastern and southern Africa, which include both "Middle Stone Age" and microlithic elements, are not so much reflective of a "Second Intermediate" transitional phase as of either mixed deposits, activity variants, or indepen- dent lithic expressions. For some years, the "Magosian" has been regarded as one of the poorest terminological constructs in Africa, and this appears to be borne out by radiocarbon evidence. At Magosi itself, the Ugandan type-site, there is now known to have been a mixture of separate occupa- tions which went unnoticed by earlier investigators.38 Elsewhere, suppos- edly "Magosian" dates cover an enormous range of time: Siachingola, Zambia (570 B.C.); Kalambo Falls, Zambia (7,600 B.C.); Pomongwe Cave, Rhodesia (13,850 B.C.); Kisese Shelter, Tanzania (29,530 B.C.);

36 R. J. Mason, "Tentative Interpretations of New Radiocarbon Dates for Stone Arte- fact Assemblages from Rose Cottage Cave, O.F.S., and Bushman Rock Shelter, Tvl.," South African Archaeological Bulletin, XXIV (1969), 58.

37 The dates are stratigraphically out of sequence. *38 G. H. Cole, "A Re-investigation of Magosi and the Magosian," Quaternaria, IX

(1967), 153-167.

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16 CREIGHTON GABEL

Montagu Cave, Cape (Howieson's Poort variant, 17,150, 21,250, >36,050, 43,950, and 48,850 B.C.),39 and Rose Cottage Cave, Orange Free State (34,150 to >48,250 B.C.).

In much of the eastern side of the continent, from the Horn to) the Cape, the epitome of microlithic tendencies is represented by numbers of assem-

blages lumped under the single term "Wilton." These are characterized by small core and flake tools, usually including many lunates and scrapers, sometimes associated with a few heavier implements such as polished axes, bored stones, and grindstones. Ceramics appear to be most common in East Africa; in South Africa, if present at all, these were usually borrowed from neighboring Bantu or Hottentot groups. While "Wilton" is a desig- nation so broadly applied in time and space as to, be practically meaning- less in some respects,40 many aspects of the stone technology and typology are suprisingly similar. One suspects that if useful subdivisions ever are worked out, they will have to be based in large part on settlement patterns, subsistence orientations, the presence and nature or absence of pottery, associated artifacts of bone or wood, and so on. For example, there are some instances in which domestic as well as wild fauna occur. The human physical type, when ascertainable, is frequently Bushmanoid, but the pos- sibility of other (e.g., Negroid) physical types cannot be ruled out. Dates cover a wide span of time, and in some areas it is abundantly clear that "Wilton" populations persisted well into the Iron Age.

Radiocarbon dates for the "Wilton" include the following:

South Africa: Grahamstown, Cape (16,790 B.C.); Matjes River Shelter, Cape (3,450 and 5,800 B.C.); Montagu Cave, Cape (5,150 B.C.); Rose Cottage Cave, Orange Free State ("Pre-Wilton" at 27,480 B.C.; Phase 2 Wilton at 4,900 B.C.; Phase 3 Wilton at A.D. 850 and A.D. 1,340); Blydefontein Shelter, Orange River (30, 1,140, and 1,690' B.C.); Wage- naar's Cave, Cape (A.D. 20, 590, 975 B.C.); Umhlanga Rocks, Natal (A.D. 1700).

Southwest Africa: Lower Numas Cave (940 and 1000 B.C. - with rock paintings); Numas Entrance Shelter (A.D. 1080).

Angola. Caninguiri Shelter (5,890, 7,720, and 8,460 B.C. - with rock paintings).

Rhodesia: Pomongwe Cave (5,660 and 5,740 B.C.); Amadzimba Cave (2,250 B.C.); Tshangula Cave (200 B.C., A.D. 830).

39 The dates are stratigraphically out of sequence, and the excavator feels the three older ones in particular are unacceptable. C. M. Keller, "C-14 Dates - Montagu Cave," South African Archaeological Bulletin, XXV (1970), 47.

40 R. Inskeep, "The Late Stone Age in Southern Africa," in W. W. Bishop and J. D. Clark, Background to Evolution in Africa (Chicago, 1967), 558-559.

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RADIOMETRIC AGE DETERMINATIONS

Zambia: Gwisho A (2,350-2,750 B.C.); Gwisho B (1,710-2,835 B.C.); Kalambo Falls (1,900 and 1,970 B.C.); Lusu Village (189 B.C.); Sia- suntwe Village (60 B.C.).

Tanzania: Kisese Shelter (8,770, 12,810, 16,240 B.C.).

Kenya: Tunnel Shelter (100 and 780 B.C.); Agoro Shelter (425 B.C.); Rangong Shelter (365 B.C.); Nyaidha Shelter (280 B.C.); Jawuoyo Shelter (90 B.C.); Abindu Shelter (30 B.C.); Randhore Shelter (A.D. 640).

Uganda: Magosi (2,180 B.C. and A.D. 1,250); Nsongezi (A.D. 1,025).

A rather similar microlithic tradition in South West Africa, the Erongo, seems more or less contemporary with the "Wilton," although only a few dates are available: Cymot Shelter (3,790 B.C.), Striped Giraffe Shelter (1,130and 2,640 B.C.), and Great Elephant Shelter (A.D. 550 and 600).

In the eastern part of South Africa, the various "Smithfield" industries seem to represent an even greater mixture of things than does the "Wil- ton." Nonmicrolithic "Early Smithfield" ("Proto-Smithfield," "Smithfield A") expressions have, been dated at Heuningneskrans Shelter, Transvaal (5,250-11,150 B.C., plus an additional date of 22,680 B.C.) and Matjes River Shelter, Cape (6,593-9,300 B.C.).41 A "Middle Smithfield" horizon at Bushman Rock, Transvaal, is placed at 7,620-10,210 B.C., and a "Proto- Smithfield" (or "Pomongwan") level in Pomongwe Cave, Rhodesia, at 7,450 B.C.

Industries such as "Smithfield B" and "Smithfield C," some microlithic and some not, are generally much later in time and may, like the regional "Wilton," be largely the handiwork of ancestral Khoisan-speakers. Dated occurrences include Waterberg (A.D. 1,080) and Magabengberg (A.D. 930) in the Transvaal, Munro's Shelter (A.D. 1,100) in the Orange Free State, and Dombozanga (A.D. 730) on the Rhodesian bolrder.

Also in southern Africa, there are a number of dated sites with lithic materials variously described as "Smithfield/Wilton," unspecified "Later Stone Age," or simply "microlithic." These include Philip Cave in South West Africa ( 1,418 B.C., supposedly associated with naturalistic rock art); Zaayfontein Shelter (A.D. 1,520, A.D. 1,220, 1,320 B.C.), Scott's Cave (A.D. 760 and 1590), Riversmead Shelter (335-695 B.C.), Robberg Cave (710 B.C.), and Bonteberg Shelter (2,555 and 100 B.C.) in the

Cape; and Emambent Shelter (1,640 B.C.), Banda Cave (3,940 B.C.),

41 Six new dates from this badly excavated site show that it was occupied from at least

1,600 to 8,000 B.C., although it was not possible to equate the samples with the original excavation levels.

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1950 A. D.

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RADIOMETRIC AGE DETERMINATIONS

and Mlaula Shelter (7,620 and 7,420 B.C.) in Swaziland. Two recently dated sites on the Cape, Robberg Cave D (A.D. 50) and Klasies River mouth (335 B.C.), contained painted gravestones. A similar stone found in the "Wilton" levels of Matjes River Shelter, if the C-14 dates are correct, would be at least 3,000 years older.

Further north in Zambia, unspecified "Later Stone Age" dates have been

reported for Kamusongolo Kopje (2,050 and 11,350 B.C.), Makwe

(3,480 B.C. to A.D. 220), and Kandanda (1,740 B.C. to A.D. 115). Microlithic occurrences in nearby Malawi include Chaminade (1,500 B.C.) and Mbande Court (2,130 to 270 B.C.) in Karonga and Fingira Shelter on the Nyika Plateau, where dates of 1,310 and 1,480 B.C. appear to be associated with schematic rock art.

One of the earliest single series of dates for a fully microlithic occur- rence has been obtained from Munyama Island on the Uganda side of Lake Victoria. Four samples there ranged in age from 7,830 B.C. to

12,975 B.C. The Ishango materials from Lake Edward in the Western Rift may

constitute a special lake environment adaptation geared to fishing and

shellfish-collecting. Very crude quartzite tools were associated with well- made barbed bone points and incised bone handles, as well as fragmentary human remains of indeterminate racial character. Extrapolated C-14 re- sults suggest an age of at least 6,000-6,500 B.C., although the possibility of an earlier date has not been ruled out.

Another unusual fishing settlement on Lake Rudolf, which included bone points and human burials, has been dated at about 5,610 B.C. More barbed bone points were recovered from Catfish Cave near Kom Ombo in Nubia underlying a deposit dated at 5,110 B.C. These, together with an undated but apparently early harpoon fragment from Gamble's Cave in the Kenya Rift and the Fayum B examples, suggest projectiles of this type were in use throughout much of northeast Africa no later than the sixth or seventh millenium B.C., just as in northwestern Europe.

The preagricultural terminal Stone Age of West Africa is still poorly defined. The largest microlithic collection thus far has come from Iwo

Eleru, north of Benin, with dates ranging from 9,250 to 5,080 B.C. The earliest of these dates was associated with a possibly Negroid burial. Microlithic elements clearly continued for a long time in West Africa, after ceramics, and probably after agriculture, were introduced (e.g., the

"Kintampo Culture" of Ghana, the "Guinea Neolithic" of the West African littoral).

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20 CREIGHTON GABEL

Distribution of prehistoric archaeological radibcarbon dates in Africa: approximate number per country

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RADIOMETRIC AGE DETERMINATIONS

In summary, having barely recovered from the shock of the nearly two-million-year antiquity assigned Olduvai Bed I hominids by potassium- argon dating, we now find ourselves faced with the fact that the earliest African hominids may be at least twice that age and therefore not confined solely to the Early Pleistocene. Although the evidence is not yet as definite on the cultural side, there is likewise a possibility that tool-making was initiated during the Pliocene. It will be interesting to see if indications of

tool-making prove to be as early as the initial appearance of Australo- pithecines and related forms.

A major chronological problem involves the need for more precise placement of Acheulian industries within the Pleistocene. Since these in- dustries may cover a total timespan of a million or more years, it will otherwise remain difficult to distinguish between synchronic (cultural/ geographical/seasonal) and diachronic variations in their typological makeup.

Increasing evidence has accumulated to suggest that microlithic indus- tries in sub-Saharan Africa in some instances antedated the end of the Pleistocene. If the appearance of microliths was, as is suspected, intimately related to the development of composite tools and weapons (including the bow and arrow), the earlier occurrences may have some implications for our evaluation of African Stone Age innovation vis-a-vis that of Europe and the Near East.

The very substantial overlapping of radiocarbon dates for certain major lithic traditions, including some once thought to be entirely sequential, has

highlighted the need for rethinking in the areas of terminology and typol-

ogy. The overall picture may indeed be a great deal more complex than

previously realized. This is even true at the local level, for example in Nubia where the existence of discrete, apparently contemporary popula- tions within very restricted geographical areas already has been demon- strated. Comparably intensive investigation may prove the same situation

prevailed in other parts of the continent.

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