Prehistoric Archaeology II: The Palaeoenvironment — the Tertiary, Quaternary, Pleistocene and Holocene, Glacials, Interglacials, Pluvials and the Evidences of Quaternary Climatic Change, Site Formation — and Lithic Tool Typology and Technology from the Lower Palaeolithic to the Neolithic

The Cenozoic era, the age of mammals, was traditionally divided into the Tertiary and Quaternary periods. The Tertiary, from the extinction of the dinosaurs about 66 million years ago to about 2.6 million years, comprises the Palaeocene (66–56), Eocene (56–34), Oligocene (34–23), Miocene (23–5.3) and Pliocene (5.3–2.6 million years): the primates radiate in the Eocene, the anthropoids appear in the Oligocene of the Fayum, the apes spread in the Miocene and the first hominins walk in the late Miocene and Pliocene. (Modern stratigraphy has replaced "Tertiary" with the Palaeogene and Neogene, but the syllabus and Indian usage keep the old name.) The Quaternary, formally beginning at 2.58 million years (moved down from 1.8 million in 2009), is the period of repeated glaciation, of the genus Homo and of stone tools; it has two epochs. The Pleistocene ("most recent"), from 2.58 million to 11,700 years ago, is the Ice Age proper, divided into the Lower or Early (2.58–0.78 million years, ending at the Brunhes–Matuyama magnetic reversal), the Middle (780,000–126,000 years) and the Upper or Late (126,000–11,700 years, the last interglacial and last glacial); the Villafranchian fauna of the early Pleistocene (Elephas, Equus, Bos) is the palaeontological marker of its beginning. The Holocene ("wholly recent"), from 11,700 years ago (about 9700 BCE) to the present, is the current interglacial, warm and comparatively stable, in which agriculture, cities and everything since arose; its subdivisions in the Blytt–Sernander scheme, from the pollen of Scandinavian bogs, are the Pre-Boreal (cool), Boreal (warm and dry), Atlantic (warm and wet — the climatic optimum, about 8,000–5,000 years ago), Sub-Boreal (drier) and Sub-Atlantic (cooler and wetter, from about 2,500 years ago). A proposed Anthropocene epoch for the present age of human impact was debated for years and rejected as a formal unit by the stratigraphers' subcommission in 2024.

The Pleistocene was not one ice age but a succession of cold glacial stages, when ice sheets spread from the poles and the mountains to cover northern Europe to the Thames and the Alps, North America to the Ohio, and the Himalaya far down its valleys, separated by warm interglacials as warm as or warmer than today. Albrecht Penck and Eduard Brückner (Die Alpen im Eiszeitalter, 1901–09) read four glaciations from the gravel terraces and moraines of the Alpine foreland and named them, from oldest to youngest, after Bavarian rivers: Günz, Mindel, Riss and Würm, with the Günz–Mindel, Mindel–Riss (the "Great Interglacial") and Riss–Würm interglacials between, later prefixed by the older Donau and Biber; the North European names are Elster, Saale and Weichsel, the British Anglian, Wolstonian and Devensian, the North American Nebraskan, Kansan, Illinoian and Wisconsin. The deep-sea oxygen-isotope record has since shown that there were not four but more than forty glacial–interglacial cycles in the Quaternary, at roughly 41,000-year intervals before about one million years and 100,000-year intervals since, paced by Milankovitch's orbital cycles (eccentricity, obliquity, precession); the Alpine names are kept as convenient labels for the last four major cold stages, and the last glaciation (Würm, MIS 4–2, about 115,000–11,700 years) reached its maximum about 21,000 years ago, when sea level stood some 120 metres lower and Britain, Sundaland and Beringia were joined to their continents. In the tropics, where ice was confined to the high mountains, the corresponding changes were in rainfall. Pluvials were wet phases with high lake levels and expanded rivers, interpluvials dry phases with dunes and shrunken lakes: the East African sequence of Kageran, Kamasian, Kanjeran and Gamblian pluvials (Wayland, Leakey, 1930s) was matched to the four Alpine glacials, and Indian workers correlated the Soan and Narmada terraces the same way. This simple equation of glacial with pluvial has been abandoned — many tropical regions were drier and windier during glacials (the Thar's dunes formed then) and wetter in interglacials and in the early Holocene monsoon maximum — but the terms remain in use for local wet and dry phases dated in their own right. Post-Pleistocene (Holocene) climate warmed rapidly after the Younger Dryas cold snap (12,900–11,700 years), reached the Atlantic optimum, and has fluctuated since — the 4.2-thousand-year drought event associated with the decline of Harappan agriculture, the Medieval Warm Period and the Little Ice Age (about 1300–1850 CE).

Site formation is the study of how an archaeological site came to be as it is found — the processes between the living community and the excavated deposit. Michael Schiffer (Behavioral Archeology, 1976; Formation Processes of the Archaeological Record, 1987) separated cultural transformation processes (C-transforms: discard, loss, caching, abandonment, burial, reuse, trampling, ploughing, looting — what people did to the material) from natural or non-cultural processes (N-transforms: burial by wind and water, erosion, redeposition by rivers, bioturbation by roots and burrowers, chemical decay, frost heave, animal gnawing and carnivore accumulation — what nature did). A river-terrace assemblage may be a redeposited mixture of many ages; a cave floor may have been sorted by water and disturbed by hyenas; an open-air site on a dune may be a deflated palimpsest. Taphonomy (Efremov, 1940) is the corresponding study of what happens to bones between death and fossilisation, and Binford's and Brain's work on carnivore bone accumulations (Brain's The Hunters or the Hunted?, 1981, on the South African cave australopithecines, victims of leopards rather than "killer apes") is its classic. Reading a site's formation is the precondition for dating it and for inferring behaviour from it, which is why the syllabus lists it beside the climatic evidences.

Stone tools are made by percussion: a hammerstone (hard hammer) or a piece of bone, antler or wood (soft hammer) strikes a core and detaches a flake, which carries a striking platform, a bulb of percussion on its ventral face and ripple marks; the core keeps the negative scar. A core tool is the shaped core itself, a flake tool the detached piece, retouched to an edge. The Lower Palaeolithic (about 2.6 million to 300,000 years) begins with the Oldowan of Olduvai and the Omo (Mode 1 in Grahame Clark's five modes): pebble tools — a pebble flaked on one face to make a chopper, or on both faces along the edge to make a chopping tool — with the sharp flakes struck from them, made by Homo habilis and early erectus. The Acheulian (from Saint-Acheul near Amiens; Mode 2; from 1.76 million years at Kokiselei in Kenya and about 1.5 million at Attirampakkam) adds the biface: the handaxe, a core worked on both faces to a pointed or ovate form with a cutting edge all round (Abbevillian or early Acheulian handaxes are thick and irregular, made with a hard hammer; later ones are thin, symmetrical and soft-hammer finished), and the cleaver, a biface with a straight transverse cutting edge at the end, often made on a large flake — the tool of Homo erectus and heidelbergensis across Africa, Europe, western Asia and India, but not east of the Movius line (1948) through India and Southeast Asia, where chopper-chopping industries persisted. The Middle Palaeolithic (about 300,000 to 40,000 years; Mode 3) is a flake-tool technology on prepared cores. The Clactonian (Clacton-on-Sea, Essex; an early flake industry of the Mindel–Riss interglacial) struck thick flakes with wide, high-angled platforms and prominent bulbs from unprepared cores by hard hammer. The Levalloisian (Levallois-Perret, a Paris suburb) prepared the core first — trimming its surface and platform so that a flake of predetermined shape and size could be struck in one blow — leaving a "tortoise core", domed like a tortoise shell, and a Levallois flake with a faceted platform; Levallois points and blades come from the same technique. The Mousterian (Le Moustier, Dordogne; the industry of the Neanderthals in Europe and of contemporaries in Africa and Asia) used Levallois and discoidal (disc-shaped, centripetally flaked) cores to make side-scrapers (racloirs) of many forms, points, denticulates and notches, which François Bordes classified into 63 types and five facies; in India the Nevasian of Sankalia is the Middle Palaeolithic flake industry on jasper and chert. The Upper Palaeolithic (about 40,000 to 10,000 years; Mode 4; the work of anatomically modern humans) turned to blades — flakes at least twice as long as wide, struck in series from a prismatic or fluted core (so called from its parallel flake scars, fluted like a column) by punch or pressure, with a prepared platform — and to tools made on them: the knife and backed blade (blunted-back blade, one edge steeply retouched so it can be held or hafted), the burin (a chisel edge made by a burin blow, for engraving bone and antler), the borer or awl (a retouched point for piercing), end-scrapers, and points of many regional kinds (Gravette points, Font-Robert tanged points, Solutrean leaf points). Bone, antler and ivory tools, personal ornaments and art appear with it.

The Mesolithic (Mode 5; in Europe from the end of the Pleistocene about 10,000 BCE to the arrival of farming, in India from about 10,000 BCE to 2,000 BCE or later in places) is defined by the microlith: a small stone tool, typically under 3 cm, made on a bladelet struck from a small fluted core — pencil-shaped and conical cores are characteristic — and shaped by steep backing or by the microburin technique, in which the bladelet is notched and snapped to leave a small triangular waste piece (the microburin) and a trapezoidal or triangular tool. Microliths are classified as non-geometric (backed blades, obliquely blunted points, lunates or crescents, points, penknife blades) and geometric (triangles, trapezes, rhomboids, lunates in strict geometric form); the geometric forms are usually the later. Their purpose was composite tools: several microliths set in a groove of bone or wood with resin made the barbs and tips of arrows, the teeth of sickles and the edges of knives and harpoons — and the bow and arrow, whose earliest secure evidence is Mesolithic in Europe (though microliths and probable arrowheads are far older in Africa), transformed hunting, as did the domestic dog, fishing gear and the exploitation of small game, shellfish and wild grain in the warmer, wetter post-glacial world. In India the microlithic industries are on chert, chalcedony, agate, jasper and quartz; their sites (Bagor, Langhnaj, Adamgarh, Sarai Nahar Rai, Bhimbetka) are the next chapter's subject, and their rock paintings show the hunts. The Neolithic (from about 9,000 BCE in the Near East, 7,000 BCE at Mehrgarh, 3,000–1,000 BCE across peninsular and north-east India) is defined by food production — cultivation and herding — and by a new lithic technology: grinding and polishing. The celt is the type tool, a ground and polished axe or adze head of fine-grained rock (basalt, dolerite, diorite, jadeite in the north-east) first roughed out by flaking, then pecked and ground on a grinding stone, and finally polished; an axe has a symmetrical edge and is hafted with the edge parallel to the handle, an adze an asymmetrical (bevelled) edge and is hafted with the edge transverse, for shaping wood; the shouldered celt of the north-east and the faceted celt of the south are regional forms. Ring stones are perforated discs of stone, made by pecking from both faces to a biconical hole, used as weights on digging sticks (and as mace heads and net sinkers); grinding stones — the saddle quern and its muller or rubber, and the mortar and pestle — process grain and are the surest sign of a plant-food economy. Chipped tools continue: microliths persist into the Neolithic and Chalcolithic (the Chalcolithic blade industries of Malwa and Jorwe are the descendants of Mesolithic microlith-making), and the "Neolithic" of the syllabus is a technological and economic stage rather than a date, which is why Burzahom's pit-dwellers and Brahmagiri's ash-mound cattle-keepers are both Neolithic though separated by a thousand miles and years.