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PREFACE
ERNESTO ABBATE, BERAKI WOLDEHAIMANOT, YOSIEF LIBSEKAL,
TEWELDE MEDHIN TECLE & LORENZO ROOK
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GEOLOGY OF THE HOMO-BEARING PLEISTOCENE DANDIERO BASIN
(BUIA REGION, ERITREAN DANAKIL DEPRESSION)
ERNESTO ABBATE, BERAKI WOLDEHAIMANOT, PIERO BRUNI, PAOLA FALORNI, MAURO PAPINI, MARIO SAGRI, SIMRET GIRMAY & TEWELDE MEDHIN TECLE
This paper deals with the geological context of the northernmost site in the East Africa Rift system which has yielded Homo erectus-like remains. They are dated ca. 1 Ma and have been found in the deltaic deposits of the Alat Formation belonging to the Dandiero group. This newly defined group crops out extensively in an elongated belt from the Gulf of Zula to the North to the Garsat area to the south. In the Buia-Dandiero area it ranges in age from the Early to the Middle Pleistocene, and incorporates six formations, from bottom up: the fluvial Bukra Sand and Gravel, the deltaic and lacustrine Alat Formation, fluvial Wara Sand and Gravel, the lacustrine Goreya Formation, the fluvio-deltaic Aro Sand and alluvial Addai Fanglomerate. This succession is bounded by two major unconformities, which separate it from the Neoproterozoic basement and from the overlaying Boulder Beds fanglomerate, and has been designated the Maebele Synthem. The latter is the result of two lacustrine transgression and regressions evidenced by two depositional sequences. The unconformities bounding the Maebele Synthem are related to the tectonic history of the basin fill and its substrate. The development of the two sequences was, instead, mainly controlled by lake level fluctuations and, hence, by climatic variations connected with the weakening and strengthening of the monsoons in the northwestern Indian ocean. The environment where the Buia Homo lived was a savannah with some scattered water pools. This environment probably extended farther north along the western coastal plain of the Red Sea, and was a preferential pathway for the dispersal of the hominids from East Africa toward Eurasia.
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MAGNETOSTRATIGRAPHY OF THE HOMO-BEARING PLEISTOCENE
DANDIERO BASIN (DANAKIL DEPRESSION, ERITREA)
ANDREA ALBIANELLI & GIOVANNI NAPOLEONE
Four magnetozones have been found in the 530 m thick profile of the Dandiero Group. The lower unit, the Bukra Sand and Gravel, extends in the R1 reversed magnetozone from 150 m below the tephra level which was used as the reference marker between the sampled sections. The normal magnetozone N1 is almost completely covered by the lacustrine and deltaic sediments of the Alat Formation, while the following reversed magnetozone contains both the Wara Sand and Gravel and the lacustrine Goreya Fm. The N2 polarity zone is completely occupied by the Aro Sand. This polarity sequence has been calibrated to the geomagnetic time scale using the Early to Middle Pleistocene age of the associated vertebrate fauna and fission-track dating. The four magnetozones were thus regarded as representing the chrons by which the Pleistocene is correlated with magnetochronology. Their three reversal boundaries provided the dates of 1.07, 0.99 and 0.78 Ma, allowing to determine average sedimentation rates close to 1 m/ky. Cyclostratigraphy of the magnetic signal, analysed by the spectral analysis of the time series across the Jaramillo and late Matuyama chrons, confirmed that value. The evidenced cyclicities were directly related to the alternating lithofacies, and both to the astronomical parameters driving the climate changes during the deposition of the Dandiero group (some five hundred thousand years). The section with the Homo site covers the Jaramillo/Matuyama boundary, and the Homo bed located 2 m below this limit is dated 0.992 Ma.
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FISSION-TRACK DATING OF A TEPHRA LAYER IN THE ALAT FORMATION OF THE
DANDIERO GROUP (DANAKIL DEPRESSION, ERITREA)
GIULIO BIGAZZI, MARIA LAURA BALESTRIERI, PIO NORELLI, MASSIMO ODDONE
& TEWELDE MEDHIN TECLE
Attempts to date a biotite separate from a tephra layer recognized near Buia (Danakil Depression, Eritrea) in the liwer part of the Homo remains – bearing Dandiero group (formerly attributed to the Danakil Formation) using the 39Ar/40Ar method failed because of xenocrystic contamination. For this reason it was applied the fission-track method on glass, since no other phases datable with this technique were present. The quality of glass was very poor for fission-track dating, because of the small size of grains. In addition, after polishing only few glass shards showed useful surfaces for track counting and only 25 spontaneous tracks were counted. The determined fission-track age - 0.75 +/- 0.16 Ma - is a rejuvenated age due to the presence of a certain amount of annealing of spontaneous tracks. An attempt to apply the plateau method for correcting this apparent age failed. A corrected age of 1.3 +/- 0.3 Ma was computed using the size-correction method. In spite of its low precision, this fission-track age represents a significant result, since it corroborates the attribution to Jaramillo Subchron of the normal magnetozone near the base of which the tephra is located.
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FOSSIL REPTILES FROM THE PLEISTOCENE HOMO-BEARING LOCALITY OF BUIA
(ERITREA, NORTHERN DANAKIL DEPRESSION)
MASSIMO DELFINO, AMAHA SEGID, DESSALE YOSIEF, JEHESKEL SHOSHANI,
LORENZO ROOK & YOSIEF LIBSEKAL
The early to early-Middle Pleistocene fossil assemblage form the Buia area (Northern Danakil Depression, Eritrea) hosts, along with Homo and several other large mammal taxa, the following reptiles: Nile Crocodile, Crocodylus niloticus, Serrated Hinged Terrapin, Pelusios cf. P. sinuatus, Nile Monitor, Varanus niloticus and African Rock Python, Python gr. sebae. All the identified taxa belong to living species. At present, these taxa do not occur in the Northern Danakil depression since it is an arid area. P. sinuatus is not a member of the Eritrean herpetofauna. Although the marked preponderance of the crocodile remains is probably connected to the taphonomy of the sites and the collecting methods used, the ecological value of the reptile fauna corroborates that of the mammals, in indicating a lacustrine or fluvio-deltaic palaeoenvironment and a tropical/subtropical or even sub-Sahelic climate. The Buia remains represent the first reported Eritrean palaeoherpetofauna.
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THE LARGE FOSSIL MAMMALS FROM FROM BUIA (ERITREA):
SYSTEMATICS, BIOCHRONOLOGY AND PALEOENVIRONMENTS
BIENVENIDO MARTÍNEZ-NAVARRO, LORENZO ROOK, AMAHA SEGID, DESSALE YOSIEF, MARCO P. FERRETTI, JEHESKEL SHOSHANI, TEWELDE MEDHIN TECLE
& YOSIEF LIBSEKAL
This paper offers a preliminary overview on the large fossil mammals (Primates, Hyaenidae, Proboscidea, Rhinocerotidae, Equidae, Hippopotamidae, Suidae, Giraffidae, and Bovidae) from the Early Pleistocene sedimentary succession of the Dandiero (Buia) Basin (Danakil Depression, Eritrea). The 1995-1997 Eritrean-italian fossil collection has been revised and studied. A few significant remains collected during the 2002-2004 field activities have also been included. Eighteen species of mammals have been identified, described and illustrated in the principal specimens. The systematic study allows general coclusions on the biochronologic and paleoenvironmental significance of the faunal assemblage. This study is completed by an analysis of “Genus Faunal Resemblance Index” (GFRI) with some well known faunal assemblages of Africa across the time span Late Pliocene – Middle Pleistocene.
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TAPHONOMIC ANALYSIS OF THE LATE EARLY PLEISTOCENE BONE REMAINS
FROM BUIA (DANDIERO BASIN, DANAKIL DEPRESSION, ERITREA):
EVIDENCE FOR LARGE MAMMAL AND REPTILE BUTCHERING
IVANA FIORE, LUCA BONDIOLI, ALFREDO COPPA, ROBERTO MACCHIARELLI, REZENE RUSSOM, HABTOM KASHAY, TEKESTE SOLOMON, LORENZO ROOK
& YOSIEF LIBSEKAL
The Early Pleistocene sedimentary succession of the Dandiero (Buia) Basin (Danakil Depression, Eritrea) has preserved a rich paleontological, paleoanthropological, and archeological record circa one million years old. Fieldwork undertaken between 1995 and 2003 led to the collection of fossil vertebrate remains now stored at the National Museum of Eritrea. Bones were recovered in different localities of the Dandiero Basin, where abundant archaeological and paleontological remains outcrop from the eroded sediments. The faunal collection of 436 animal bones from the Buia Basin, mostly derived from Uadi Aalad area, have undergone taphonomic analysis. Even though bone surfaces are poorly preserved due to abrasion, our work demonstrates carcass exploitation. Some specimens, mostly representing Hippopotamus gorgops and medium- to large-sized bovids, show traces of butchering left by stone tools. We also document, as far as we know for the first time, a single case of butchering involving a femur of a crocodile.
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CHARACTERIZATION OF LITHIC COMPLEXES FROM BUIA
(DANDIERO BASIN, DANAKIL DEPRESSION, ERITREA)
FABIO MARTINI, YOSIEF LIBSEKAL, OMAR FILIPPI, ASMERET GHEBRE/HER, HABTOM KASHAY, ASMERET KIROS, GABRIELE MARTINO, DAWIT OKUBATSION,
AMAHA SEGID, TEKESTE SOLOMON, ZELALEM TEKA, DESSALE YOSIEF
& SAMUEL YAMANE
This paper discusses a very partial sampling of the archeological evidence found in more than 200 sites containing lithic artefacts and faunal remains which have been surveyed in the Dandiero (Buia) Basin (Danakil Depression, Eritrea). All the lithic complexes are referred to the Acheulean. The authors present the results of a preliminary study carried on some of the most important assemblages, especially the complex referred to the Homo-bearing levels. The lithic assemblages are characterized by different frequencies of hand-axes, cleavers, choppers and flakes. The techno-typological characters of the artefacts, all of which coform to an Acheulean standard, allow us to propose some preliminary hypotheses about their variability. The analyzed assemblages are then compared to the Early Paleolithic lithic complexes in east Africa.
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THE LATE EARLY PLEISTOCENE HUMAN REMAINS FROM BUIA, DANAKIL DEPRESSION, ERITREA
ROBERTO MACCHIARELLI, LUCA BONDIOLI, MARIO CHECH, ALFREDO COPPA, IVANA FIORE, REZENE RUSSOM, FRANCESCO VECCHI, YOSIEF LIBSEKAL & LORENZO ROOK
The Early Pleistocene sedimentary succession of the Dandiero (Buia) Basin (Danakil Depression, Eritrea) has preserved a rich paleontological, paleoanthropological, and archeological record. Fieldwork undertaken between 1995 and 2003 on a site at Uadi Aalad (Abbate et al. 1998) led to the discovery of one-million-year-old human remains. They consist of a cranium in excellent preservation condition (UA-31), two permanent teeth (UA-222 and UA-369), and three pelvic portions (UA-173, UA-405 and UA-466, the latter recovered on 2003). The cranium and the postcranial remains represent a single adult individual, likely of female sex. The cranium evidences a blend of "erectus-like" and progressive morpho-architectural features, the latter more commonly found in the Middle Pleistocene. Preparation and restoration of the specimens (notably, of the virtually complete UA-31 face) were only completed on September 2003. The revision, refinement, and integration of our previous analytical and interpretative work (cf. Abbate et al. 1998; Macchiarelli et al. 2002) is in progress within the context of the paleoanthropological reord currently available for the African Early to Middle Pleistocene.
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