Misplaced Pages

#819180

73-602: The area includes the largest known Stone Age burial site in Northern Europe and was first settled ca. 5000 BC. The present town began to develop in 1864, when a bridge over the Salaca river was constructed. During World War II , Mazsalaca was under German occupation from 4 July 1941 until 25 September 1944. It was administered as a part of the Generalbezirk Lettland of Reichskommissariat Ostland . In October 2009

146-465: A meteorite crater was found near the town, which later turned out to be hoax as part of marketing campaign of telecommunication company Tele2 . People who were born, lived in Mazsalaca: This Vidzeme location article is a stub . You can help Misplaced Pages by expanding it . Stone Age Paleolithic Epipalaeolithic Mesolithic Neolithic The Stone Age

219-728: A conference in anthropology held by the Wenner-Gren Foundation, at Burg Wartenstein Castle, which it then owned in Austria, attended by the same scholars that attended the Pan African Congress, including Louis Leakey and Mary Leakey , who was delivering a pilot presentation of her typological analysis of Early Stone Age tools, to be included in her 1971 contribution to Olduvai Gorge , "Excavations in Beds I and II, 1960–1963." However, although

292-414: A feedback with one another, controlled by oblique rifting conditions. According to this theory, lithospheric thinning generates volcanic activity, further increasing magmatic processes such as intrusions and numerous small plumes. These processes further thin the lithosphere in saturated areas, making the thinning lithosphere behave like a mid-ocean ridge . According to marine geologist Kathleen Crane ,

365-420: A hammerstone to obtain large and small pieces with one or more sharp edges. The original stone is called a core; the resultant pieces, flakes. Typically, but not necessarily, small pieces are detached from a larger piece, in which case the larger piece may be called the core and the smaller pieces the flakes . The prevalent usage, however, is to call all the results flakes, which can be confusing. A split in half

438-755: A new Lower Paleolithic tool, the hand axe, appeared. The earliest European hand axes are assigned to the Abbevillian industry , which developed in northern France in the valley of the Somme River ; a later, more refined hand-axe tradition is seen in the Acheulian industry , evidence of which has been found in Europe, Africa, the Middle East, and Asia. Some of the earliest known hand axes were found at Olduvai Gorge (Tanzania) in association with remains of H. erectus . Alongside

511-633: A number of active and dormant volcanoes, among them: Mount Kilimanjaro , Mount Kenya , Mount Longonot , Menengai Crater, Mount Karisimbi , Mount Nyiragongo , Mount Meru and Mount Elgon , as well as the Crater Highlands in Tanzania. Although most of these mountains lie outside of the rift valley, the EAR created them. Notable active examples of EAR volcanism include Erta Ale , Dalaffilla (also called Gabuli, Alu-Dalafilla), and Ol Doinyo Lengai . Erta Ale

584-401: A pre-Cambrian weakness in the crust, a suture zone of multiple cratons , displacement along large boundary faults, and the development of deep asymmetric basins. The second stage of rifting was characterized by the deactivation of large boundary faults, the development of internal fault segments, and the concentration of magmatic activity towards the rifts. Today, the narrow rift segments of

657-600: A separate Copper Age or Bronze Age. Moreover, the technologies included in those 'stages', as Goodwin called them, were not exactly the same. Since then, the original relative terms have become identified with the technologies of the Paleolithic and Mesolithic, so that they are no longer relative. Moreover, there has been a tendency to drop the comparative degree in favor of the positive: resulting in two sets of Early, Middle and Late Stone Ages of quite different content and chronologies. By voluntary agreement, archaeologists respect

730-752: A time known as the Copper Age (or more technically the Chalcolithic or Eneolithic, both meaning 'copper–stone'). The Chalcolithic by convention is the initial period of the Bronze Age. The Bronze Age was followed by the Iron Age . The transition out of the Stone Age occurred between 6000 and 2500  BC for much of humanity living in North Africa and Eurasia . The first evidence of human metallurgy dates to between

803-461: A west-facing scarp (east-plunging arch) along the southern half of its length that rises to 2,300 m (7,500 ft) above the sea floor. Its movement is concurrent with the EAR. Over time, many theories have tried to clarify the evolution of the East African Rift. In 1972 it was proposed that the EAR was not caused by tectonic activity, but rather by differences in crustal density. Since

SECTION 10

#1733092534820

876-565: A wide range of techniques derived from multiple fields. The work of archaeologists in determining the paleocontext and relative sequence of the layers is supplemented by the efforts of geologic specialists in identifying layers of rock developed or deposited over geologic time; of paleontological specialists in identifying bones and animals; of palynologists in discovering and identifying pollen, spores and plant species; of physicists and chemists in laboratories determining ages of materials by carbon-14 , potassium-argon and other methods. The study of

949-779: Is a basaltic shield volcano in the Afar Region of northeastern Ethiopia, active continuously since at least 1967, with a summit lava lake documented since at least 1906. The 2008 eruption of Dalafilla, its only documented activity since the start of the Holocene , is the largest recorded eruption in Ethiopian history. Ol Doinyo Lengai is currently the only active natrocarbonatite volcano on Earth. Its magma contains almost no silica; typical lava flows have viscosities of less than 100 Pa⋅s, comparable to olive oil at 26 °C (79 °F). EAR-related volcanic structures with dated activity since

1022-447: Is a suitable tool to investigate Earth's subsurface structures deeper than the crust. It is an inverse problem technique that models which are the velocities of the inner Earth that reproduce the seismographic data recorded all around the world. Recent improvements of tomographic Earth models of P wave and S wave velocities suggest that a superplume upwelling from the lower mantle at the northeastern EAR feeds plumes of smaller scale into

1095-475: Is associated with the remains of Neanderthal man . The earliest documented stone tools have been found in eastern Africa, manufacturers unknown, at the 3.3 million-year-old site of Lomekwi 3 in Kenya. Better known are the later tools belonging to an industry known as Oldowan , after the type site of Olduvai Gorge in Tanzania. The tools were formed by knocking pieces off a river pebble, or stones like it, with

1168-537: Is called bipolar flaking. Consequently, the method is often called "core-and-flake". More recently, the tradition has been called "small flake" since the flakes were small compared to subsequent Acheulean tools . The essence of the Oldowan is the making and often immediate use of small flakes. Another naming scheme is "Pebble Core Technology (PBC)": Pebble cores are ... artifacts that have been shaped by varying amounts of hard-hammer percussion. Various refinements in

1241-573: Is generally cool and strong. Many cratons are found throughout the EAR, such as the Tanzania and Kaapvaal cratons . The cratons are thick, and have survived for billions of years with little tectonic activity. They are characterized by greenstone belts , tonalites , and other high-grade metamorphic lithologies. The cratons are of significant importance in terms of mineral resources , with major deposits of gold, antimony, iron, chromium and nickel. A large volume of continental flood basalts erupted during

1314-474: Is in the nature of this boundary. If there is no distinct boundary, then the population of A suddenly stopped using the customs characteristic of A and suddenly started using those of B, an unlikely scenario in the process of evolution . More realistically, a distinct border period, the A/B transition, existed, in which the customs of A were gradually dropped and those of B acquired. If transitions do not exist, then there

1387-612: Is no proof of any continuity between A and B. The Stone Age of Europe is characteristically in deficit of known transitions. The 19th and early 20th-century innovators of the modern three-age system recognized the problem of the initial transition, the "gap" between the Paleolithic and the Neolithic. Louis Leakey provided something of an answer by proving that man evolved in Africa. The Stone Age must have begun there to be carried repeatedly to Europe by migrant populations. The different phases of

1460-555: Is now considered to be a facies of Acheulean , while Sangoan is a facies of Lupemban . Magosian is "an artificial mix of two different periods". Once seriously questioned, the intermediates did not wait for the next Pan African Congress two years hence, but were officially rejected in 1965 (again on an advisory basis) by Burg Wartenstein Conference #29, Systematic Investigation of the African Later Tertiary and Quaternary ,

1533-582: Is possible to speak of a general 'Stone Age' period for the whole of humanity, some groups never developed metal- smelting technology, and so remained in the so-called 'Stone Age' until they encountered technologically developed cultures. The term was innovated to describe the archaeological cultures of Europe. It may not always be the best in relation to regions such as some parts of the Indies and Oceania, where farmers or hunter-gatherers used stone for tools until European colonisation began. Archaeologists of

SECTION 20

#1733092534820

1606-639: The 6th and 5th millennia  BC in the archaeological sites of the Vinča culture , including Majdanpek , Jarmovac , Pločnik , Rudna Glava in modern-day Serbia. Ötzi the Iceman , a mummy from about 3300 BC, carried with him a copper axe and a flint knife. In some regions, such as Sub-Saharan Africa , the Stone Age was followed directly by the Iron Age. The Middle East and Southeast Asian regions progressed past Stone Age technology around 6000 BC. Europe, and

1679-653: The Albertine Rift , and farther south, the valley of Lake Malawi . The rift also continues offshore from the coast of Mozambique along the Kerimba and Lacerda grabens , which are joined by the Davie Ridge, a 2,200 km-long (1,400 mi) relic fracture zone that cuts across the West Somali basin, straddling the boundary between Tanzania and Mozambique. The Davie Ridge ranges between 30–120 km (19–75 mi) wide, with

1752-542: The Ethiopian Highlands and the Kenya Highlands are hotspots of higher rainfall amid the semi-arid to arid lowlands of East Africa. Lakes which form within the rift, including Lake Victoria , have a large effect on regional climate. They are a source of water vapour, and also lead to the formation of lake breeze systems , which affect weather across large areas of East Africa. The east to west river valleys within

1825-586: The Fauresmith and Sangoan technologies, and the Second Intermediate Period between Middle and Later, to encompass the Magosian technology and others. The chronologic basis for the definition was entirely relative. With the arrival of scientific means of finding an absolute chronology, the two intermediates turned out to be will-of-the-wisps . They were in fact Middle and Lower Paleolithic . Fauresmith

1898-627: The Oligocene , with the majority of the volcanism coinciding with the opening of the Red Sea and the Gulf of Aden approximately 30 Ma. The composition of the volcanics are a continuum of ultra-alkaline to tholeiitic and felsic rocks. It has been suggested that the diversity of the compositions could be partially explained by different mantle source regions. The EAR also cuts through old sedimentary rocks deposited in ancient basins. The East African Rift Zone includes

1971-850: The Victoria microplate to the north, and the Rovuma and Lwandle microplates to the south. The Victoria microplate is rotating anti-clockwise with respect to the African plate. Its rotation is caused by the configuration of mechanically weaker and stronger lithospheric regions in the EARS. Many of the African Great Lakes lie within the Rift Valley. A series of distinct rift basins, the East African Rift System extends over thousands of kilometers. North of

2044-440: The genus Homo , and possibly by the earlier partly contemporaneous genera Australopithecus and Paranthropus . Bone tools have been discovered that were used during this period as well but these are rarely preserved in the archaeological record . The Stone Age is further subdivided by the types of stone tools in use. The Stone Age is the first period in the three-age system frequently used in archaeology to divide

2117-500: The geologic time scale : The succession of these phases varies enormously from one region (and culture ) to another. The Paleolithic or Palaeolithic (from Greek: παλαιός, palaios , "old"; and λίθος, lithos , "stone" lit. "old stone", coined by archaeologist John Lubbock and published in 1865) is the earliest division of the Stone Age. It covers the greatest portion of humanity's time (roughly 99% of "human technological history", where "human" and "humanity" are interpreted to mean

2190-482: The upper mantle . Parallel to geological and geophysical measures (e.g. isotope ratios and seismic velocities) it is constructive to test hypotheses on computer based geodynamical models. A 3D numerical geodynamic model of the plume-crust coupling was capable of reproducing the lateral asymmetry of the EAR around the Tanzania craton . Numerical modeling of plume-induced continental break-up shows two distinct stages, crustal rifting followed by lithospheric breakup, and

2263-459: The 1990s, evidence has been found in favor of mantle plumes beneath the EAR. Others proposed an African superplume causing mantle deformation. Although the effects of deep-rooted mantle plumes are an important hypothesis, their location and dynamics are poorly understood, and a matter of active research. The question is still debated. The most recent and accepted view is the theory put forth in 2009: that magmatism and plate tectonics have

Mazsalaca - Misplaced Pages Continue

2336-909: The Afar triple junction, the rift follows two paths: west to the Red Sea Rift and east to the Aden Ridge in the Gulf of Aden . Southward from the Afar triple junction , the EAR consists of two main branches. The Eastern Rift Valley (also known as Gregory Rift ) includes the Main Ethiopian Rift , runs southward from the Afar triple junction, and continues south as the Kenyan Rift Valley, then transects Congo DR , Uganda , Rwanda , Burundi , Zambia , Tanzania , Malawi and Mozambique . The Western Rift Valley includes

2409-467: The East African Rift system form zones of localized strain. These rifts are the result of the actions of numerous normal faults which are typical of all tectonic rift zones. As aforementioned, voluminous magmatism and continental flood basalts characterize some of the rift segments, while other segments, such as the Western branch, have only very small volumes of volcanic rock. The African continental crust

2482-572: The Nile valley. Consequently, they proposed a new system for Africa, the Three-stage System. Clark regarded the Three-age System as valid for North Africa; in sub-Saharan Africa, the Three-stage System was best. In practice, the failure of African archaeologists either to keep this distinction in mind, or to explain which one they mean, contributes to the considerable equivocation already present in

2555-595: The Somali Jet) in the western Indian Ocean . The Somali Jet supplies water vapour for the high rainfall during the Indian Monsoon and is responsible for roughly half the global cross-equatorial atmospheric mass flux in the lower-branch of Hadley Circulation . The Rift Valley in East Africa has been a rich source of hominid fossils that allow the study of human evolution. The rapidly eroding highlands quickly filled

2628-521: The Stone Age ended in a given area. In Europe and North America, millstones were in use until well into the 20th century, and still are in many parts of the world. The terms "Stone Age", "Bronze Age", and "Iron Age" are not intended to suggest that advancements and time periods in prehistory are only measured by the type of tool material, rather than, for example, social organization , food sources exploited, adaptation to climate, adoption of agriculture, cooking, settlement , and religion. Like pottery ,

2701-407: The Stone Age has never been limited to stone tools and archaeology, even though they are important forms of evidence. The chief focus of study has always been on the society and the living people who belonged to it. Useful as it has been, the concept of the Stone Age has its limitations. The date range of this period is ambiguous, disputed, and variable, depending upon the region in question. While it

2774-621: The Stone Age thus could appear there without transitions. The burden on African archaeologists became all the greater, because now they must find the missing transitions in Africa. The problem is difficult and ongoing. After its adoption by the First Pan African Congress in 1947, the Three-Stage Chronology was amended by the Third Congress in 1955 to include a First Intermediate Period between Early and Middle, to encompass

2847-462: The Stone Age. In Sub-Saharan Africa, however, iron-working technologies were either invented independently or came across the Sahara from the north (see iron metallurgy in Africa ). The Neolithic was characterized primarily by herding societies rather than large agricultural societies, and although there was copper metallurgy in Africa as well as bronze smelting, archaeologists do not currently recognize

2920-526: The decisions of the Pan-African Congress on Prehistory , which meets every four years to resolve the archaeological business brought before it. Delegates are actually international; the organization takes its name from the topic. Louis Leakey hosted the first one in Nairobi in 1947. It adopted Goodwin and Lowe's 3-stage system at that time, the stages to be called Early, Middle and Later. The problem of

2993-488: The discovery of these "Lomekwian" tools, the oldest known stone tools had been found at several sites at Gona, Ethiopia , on sediments of the paleo- Awash River , which serve to date them. All the tools come from the Busidama Formation, which lies above a disconformity , or missing layer, which would have been from 2.9 to 2.7  mya . The oldest sites discovered to contain tools are dated to 2.6–2.55 mya. One of

Mazsalaca - Misplaced Pages Continue

3066-533: The early Stone Age, when species prior to Homo may have manufactured tools. According to the age and location of the current evidence, the cradle of the genus is the East African Rift System, especially toward the north in Ethiopia , where it is bordered by grasslands . The closest relative among the other living primates , the genus Pan , represents a branch that continued on in the deep forest, where

3139-400: The first to transition away from hunter-gatherer societies into the settled lifestyle of inhabiting towns and villages as agriculture became widespread . In the chronology of prehistory, the Neolithic era usually overlaps with the Chalcolithic ("Copper") era preceding the Bronze Age. The Stone Age is contemporaneous with the evolution of the genus Homo , with the possible exception of

3212-702: The genus Homo ), extending from 2.5 or 2.6 million years ago, with the first documented use of stone tools by hominins such as Homo habilis , to the end of the Pleistocene around 10,000 BC. The Paleolithic era ended with the Mesolithic , or in areas with an early neolithisation , the Epipaleolithic . At sites dating from the Lower Paleolithic Period (about 2,500,000 to 200,000 years ago), simple pebble tools have been found in association with

3285-576: The grasslands of the rift, Homo erectus , the predecessor of modern humans, found an ecological niche as a tool-maker and developed a dependence on it, becoming a "tool-equipped savanna dweller". The oldest indirect evidence found of stone tool use is fossilised animal bones with tool marks; these are 3.4 million years old and were found in the Lower Awash Valley in Ethiopia. Archaeological discoveries in Kenya in 2015, identifying what may be

3358-569: The hand-axe tradition, there developed a distinct and very different stone-tool industry, based on flakes of stone: special tools were made from worked (carefully shaped) flakes of flint. In Europe, the Clactonian industry is one example of a flake tradition. The early flake industries probably contributed to the development of the Middle Paleolithic flake tools of the Mousterian industry , which

3431-495: The intermediate periods were gone, the search for the transitions continued. In 1859 Jens Jacob Worsaae first proposed a division of the Stone Age into older and younger parts based on his work with Danish kitchen middens that began in 1851. In the subsequent decades this simple distinction developed into the archaeological periods of today. The major subdivisions of the Three-age Stone Age cross two epoch boundaries on

3504-624: The journal Annals of the South African Museum . By then, the dates of the Early Stone Age, or Paleolithic , and Late Stone Age, or Neolithic ( neo = new), were fairly solid and were regarded by Goodwin as absolute. He therefore proposed a relative chronology of periods with floating dates, to be called the Earlier and Later Stone Age. The Middle Stone Age would not change its name, but it would not mean Mesolithic . The duo thus reinvented

3577-638: The late 19th and early 20th centuries CE, who adapted the three-age system to their ideas, hoped to combine cultural anthropology and archaeology in such a way that a specific contemporaneous tribe could be used to illustrate the way of life and beliefs of the people exercising a particular Stone-Age technology. As a description of people living today, the term Stone Age is controversial. The Association of Social Anthropologists discourages this use, asserting: To describe any living group as 'primitive' or 'Stone Age' inevitably implies that they are living representatives of some earlier stage of human development that

3650-568: The literature. There are in effect two Stone Ages, one part of the Three-age and the other constituting the Three-stage. They refer to one and the same artifacts and the same technologies, but vary by locality and time. The three-stage system was proposed in 1929 by Astley John Hilary Goodwin, a professional archaeologist, and Clarence van Riet Lowe , a civil engineer and amateur archaeologist, in an article titled "Stone Age Cultures of South Africa" in

3723-420: The majority of humankind has left behind. In the 1920s, South African archaeologists organizing the stone tool collections of that country observed that they did not fit the newly detailed Three-Age System. In the words of J. Desmond Clark : It was early realized that the threefold division of culture into Stone, Bronze and Iron Ages adopted in the nineteenth century for Europe had no validity in Africa outside

SECTION 50

#1733092534820

3796-459: The most striking circumstances about these sites is that they are from the Late Pliocene , where prior to their discovery tools were thought to have evolved only in the Pleistocene . Excavators at the locality point out that: ... the earliest stone tool makers were skilled flintknappers  ... The possible reasons behind this seeming abrupt transition from the absence of stone tools to

3869-520: The oldest evidence of hominin use of tools known to date, have indicated that Kenyanthropus platyops (a 3.2 to 3.5-million-year-old Pliocene hominin fossil discovered in Lake Turkana, Kenya, in 1999) may have been the earliest tool-users known. The oldest stone tools were excavated from the site of Lomekwi 3 in West Turkana , northwestern Kenya, and date to 3.3 million years old. Prior to

3942-478: The onset of the Miocene , 22–25 million years ago. It was formerly considered to be part of a larger Great Rift Valley that extended north to Asia Minor . A narrow zone, the rift is a developing divergent tectonic plate boundary where the African plate is in the process of splitting into two tectonic plates, called the Somali plate and the Nubian plate , at a rate of 6–7 mm (0.24–0.28 in) per year. The rift system consists of three microplates,

4015-442: The onset of the Holocene include approximately 50 in Ethiopia, 17 in Kenya , and 9 in Tanzania . The EAR is the largest seismically active rift system on Earth today. The majority of earthquakes occur near the Afar Depression, with the largest typically occurring along or near major border faults. Seismic events in the past century are estimated to have reached a maximum moment magnitude of 7.0. The seismicity trends parallel to

4088-468: The presence thereof include ... gaps in the geological record. The species that made the Pliocene tools remains unknown. Fragments of Australopithecus garhi , Australopithecus aethiopicus , and Homo , possibly Homo habilis , have been found in sites near the age of the Gona tools. In July 2018, scientists reported the discovery in China of the known oldest stone tools outside Africa, estimated at 2.12 million years old. Innovation in

4161-479: The primates evolved. The rift served as a conduit for movement into southern Africa and also north down the Nile into North Africa and through the continuation of the rift in the Levant to the vast grasslands of Asia. Starting from about 4 million years ago ( mya ) a single biome established itself from South Africa through the rift, North Africa, and across Asia to modern China. This has been called "transcontinental 'savannahstan ' " recently. Starting in

4234-482: The remains of what may have been the earliest human ancestors. A somewhat more sophisticated Lower Paleolithic tradition, known as the Chopper chopping tool industry, is widely distributed in the Eastern Hemisphere. This tradition is thought to have been the work of the hominin species named Homo erectus . Although no such fossil tools have yet been found, it is believed that H. erectus probably made tools of wood and bone as well as stone. About 700,000 years ago,

4307-431: The rest of Asia became post-Stone Age societies by about 4000 BC. The proto-Inca cultures of South America continued at a Stone Age level until around 2000 BC, when gold, copper, and silver made their entrance. The peoples of the Americas notably did not develop a widespread behavior of smelting bronze or iron after the Stone Age period, although the technology existed. Stone tool manufacture continued even after

4380-488: The rift could eventually cause eastern Africa to separate from the mainland, although this potential event could take tens of millions of years. Studies that contribute to the broader understanding on the evolution of rifts can be grouped into the techniques of isotope geochemistry, seismic tomography and geodynamical modeling. The varying geochemical signatures of a suite of Ethiopian lavas suggest multiple plume sources: at least one of deep mantle origin, and one from within

4453-513: The rift system, including the Turkana Channel in northern Kenya and the Zambezi river valley, concentrate low-level easterly winds and accelerate them towards Central Africa . This leaves East Africa drier than it otherwise would be, and also supports the high rainfall in the Congo Basin rainforest . The formation of the east–west valleys could in turn be important for the aridification of East Africa over millions of years. The barrier presented by EARS concentrates monsoonal winds (known as

SECTION 60

#1733092534820

4526-451: The rift system, with a shallow focal depth of 12–15 km (7.5–9.3 mi) beneath the rift axis. Further away from the rift axis, focal depths can be below 30 km (19 mi). Focal mechanism solutions strike NE and frequently demonstrate normal dip-slip faulting, although left-lateral motion is also observed. The East African Rift system affects regional, continental and even global climate. Regions of higher elevation, including

4599-486: The scientific study of the lithic reduction of the raw materials and methods used to make the prehistoric artifacts that are discovered. Much of this study takes place in the laboratory in the presence of various specialists. In experimental archaeology , researchers attempt to create replica tools, to understand how they were made. Flintknappers are craftsmen who use sharp tools to reduce flintstone to flint tool . In addition to lithic analysis, field prehistorians use

4672-411: The shape have been called choppers, discoids, polyhedrons, subspheroid, etc. To date no reasons for the variants have been ascertained: From a functional standpoint, pebble cores seem designed for no specific purpose. East African Rift The East African Rift ( EAR ) or East African Rift System ( EARS ) is an active continental rift zone in East Africa . The EAR began developing around

4745-411: The subcontinental lithosphere. In accordance, a 2014 study compares the geochemical signature of rare earth isotopes from xenoliths and lava samples collected in the EAR. The results corroborate the coexistence of a superplume "common to the entire rift" with another mantle material source being either of subcontinental type or of mid-ocean ridge type. The geophysical method of seismic tomography

4818-403: The technique of smelting ore is regarded as the end of the Stone Age and the beginning of the Bronze Age . The first highly significant metal manufactured was bronze , an alloy of copper and tin or arsenic , each of which was smelted separately. The transition from the Stone Age to the Bronze Age was a period during which modern people could smelt copper, but did not yet manufacture bronze,

4891-418: The timeline of human technological prehistory into functional periods, with the next two being the Bronze Age and the Iron Age , respectively. The Stone Age is also commonly divided into three distinct periods: the earliest and most primitive being the Paleolithic era; a transitional period with finer tools known as the Mesolithic era; and the final stage known as the Neolithic era. Neolithic peoples were

4964-404: The transitions in archaeology is a branch of the general philosophic continuity problem, which examines how discrete objects of any sort that are contiguous in any way can be presumed to have a relationship of any sort. In archaeology, the relationship is one of causality . If Period B can be presumed to descend from Period A, there must be a boundary between A and B, the A–B boundary. The problem

5037-472: The typology of the stone tools combined with the relative sequence of the types in various regions provide a chronological framework for the evolution of humanity and society. They serve as diagnostics of date, rather than characterizing the people or the society. Lithic analysis is a major and specialised form of archaeological investigation. It involves the measurement of stone tools to determine their typology, function and technologies involved. It includes

5110-408: The upwelling between stages of an upper mantle plume. Prior to the rift's formation, enormous continental flood basalts erupted, uplifting the Ethiopian , Somali, and East African plateaus. The first stage of rifting of the EAR was characterized by rift localization and magmatism along the entire rift zone. Periods of extension alternated with relative inactivity. There was also the reactivation of

5183-455: The valley with sediments, creating a favorable environment for the preservation of remains. The bones of several hominid ancestors of modern humans have been found here, including those of " Lucy ", a partial australopithecine skeleton discovered by anthropologist Donald Johanson dating back over 3 million years. Richard and Mary Leakey have also done significant work in this region. In 2008, two other hominid ancestors were discovered here:

5256-458: Was a broad prehistoric period during which stone was widely used to make stone tools with an edge, a point, or a percussion surface. The period lasted for roughly 3.4 million years and ended between 4000 BC and 2000 BC, with the advent of metalworking . It therefore represents nearly 99.3% of human history. Though some simple metalworking of malleable metals, particularly the use of gold and copper for purposes of ornamentation,

5329-607: Was known in the Stone Age, it is the melting and smelting of copper that marks the end of the Stone Age. In Western Asia , this occurred by about 3000 BC, when bronze became widespread. The term Bronze Age is used to describe the period that followed the Stone Age, as well as to describe cultures that had developed techniques and technologies for working copper alloys (bronze: originally copper and arsenic, later copper and tin) into tools, supplanting stone in many uses. Stone Age artifacts that have been discovered include tools used by modern humans, by their predecessor species in

#819180