Although there are many areas with very old geological formations (Figure 1.2: Crystalline Rocks), the main lines of Greek topography were formed in recent geological time, resulting from that extraordinary deformation of the Earth’s crust called the Alpine
The Complete Archaeology of Greece: From Hunter-Gatherers to the 20th Century AD, First Edition. John Bintliff. © 2012 John Bintliff. Published 2012 by Blackwell Publishing Ltd.
Figure 1.1 Distribution of the major modern olive-production zones with key Bronze Age sites indicated. The shading from A to C indicates decreasing olive yields, D denotes no or minimal production. Major Bronze Age sites are shown with crosses, circles, and squares.
C. Renfrew, The Emergence of Civilization (Study in Prehistory), London 1972, Figure 18.12. © 1972 Methuen & Co. Reproduced by permission of Taylor & Francis Books UK.
Orogeny, or mountain-building episode, which not only put in place the major Greek mountain ranges but the Alps and the Himalayas (Attenborough 1987, Higgins and Higgins 1996). In the first period of the Tertiary geological era (the Palaeogene), 40—20 million years ago, as the crustal plates which make up the
Basal rocks of Africa and Eurasia were crushed together, the bed of a large intervening ocean, Tethys, was compressed between their advancing masses and thrust upwards into high folds, like a carpet pushed from both ends. Those marine sediments became folded mountains oflimestone (Figure 1.2: Limestone).
Figure 1.2 Major geological zones of Greece.
H. C. Darby et al., Naval Geographical Intelligence Handbook, Greece, vol. 1. London: Naval Intelligence Division 1944, Figure 4.
This plate-tectonic compression created an arc-formed alignment of Alpine mountains and associated earthquake and volcanic belts (Figure 1.2: Volcanic Rocks), which begins as a NW-SE line for the Mainland mountain folds, then curves eastwards across the center of the Aegean Sea, as the E-W orientation of Crete illustrates, and also the associated island arc of volcanoes from Methana to Santorini, to be continued in the E-W ridges ofthe Western Mainland ofAnatolia-Turkey (Friedrich 2000). The Ionian and Aegean seas have been formed by differential sinking of those lateral parts of the Alpine arc, creating the Aegean and Ionian Islands out of former mountain ridges, hence their often rocky appearance. But also there have been tectonic ruptures in different alignments, the most notable being that E-W downward fault which forms the Gulf of Corinth. The artificial cutting of the Corinth Canal in 1893 accomplished the removal of the remaining 8 km stretch left by Nature.
These plate-tectonic forces still operate today, since the Aegean region forms an active interface between the southerly African and northerly Eurasian blocks, and is itself an unstable agglomerate of platelets. Where zones of the Earth’s crust are clashing, and ride against, or force themselves under or over each other, there are notorious secondary effects: frequent earthquakes and arcs of volcanoes set behind the active plate boundaries (Color Plate 1.1). Recurrent Greek earthquakes are a tragic reality, notably along the Gulf of Corinth, and the same zone curves into Turkey with equally dire consequences. The volcanic arc runs from the peninsula of Methana in the Eastern Peloponnese through the Cycladic islands of Melos and Santorini-Thera. A secondary arc of earthquake sensitivity runs closer to Crete and its mark punctuates that island’s history and prehistory. Around 1550 years ago, a violent earthquake through the Eastern Mediterranean elevated Western Crete by up to 9 meters (Kelletat 1991), lifting Phalasarna harbor out of the ocean (Frost and Hadjidaki 1990).
The mostly limestone mountains of Mainland Greece and Crete, as young ranges, are high and vertiginous, even close to the sea. Subsequently these characteristics encouraged massive erosion, especially as sea levels rose and sank but ultimately settled at a relatively low level to these young uplands. As a result, between the limestone ridges there accumulated masses of eroded debris in shallow water, later compressed into rock itself, flysch, whose bright shades of red, purple or green enliven the lower slopes of the rather monotonously greyscale, limestone high relief of Greece (Figure 1.2: Sandstones and Flysch). For a long period in the next subphase of the Tertiary era, the Neogene, alongside these flysch accumulations, episodes of intermediate sea level highs deposited marine and freshwater sediments in the same areas of low to medium attitude terrain over large areas of Greece. These produced rocks varying with depositional context from coarse cobbly conglomerates of former torrents or beaches, through sandstones of slower river and marine currents, to fine marly clays created in still water (Figure 1.2: Tertiary Sands and Clays, Tertiary Conglomerates).
During the current geological era, the Quaternary, from two million years ago, the Earth has been largely enveloped in Ice Ages, with regular shorter punctuations of global warming called Interglacials, each sequence lasting some 100,000 years. Only in the highest Greek mountains are there signs of associated glacial activity, the Eastern Mediterranean being distant from the coldest zones further north in Eurasia. More typical for Ice Age Greece were alternate phases of cooler and wetter climate and dry to hyperarid cold climate. Especially in those Ice Age phases of minimal vegetation, arid surfaces and concentrated rainfall released immense bodies of eroded upland sediments, which emptied into the internal and coastal plains of Greece, as well as forming giant alluvial (riverborne) and colluvial (slopewash) fans radiating out from mountain and hill perimeters. We are fortunate to live in a warm Interglacial episode called the Holocene, which began at the end of the last Ice Age some 12,000 years ago. Alongside persistent plate-tectonic effects — earthquakes around Corinth, one burying the Classical city of Helike (Soter et al. 2001), earthquakes on Crete, and the Bronze Age volcanic eruption of Thera (Bruins et al. 2008) — the Greek landscape has witnessed the dense infilling of human communities to levels far beyond the low density hunter-gatherer bands which occupied it in the pre-Holocene stages of the Quaternary era or “Pleistocene” period.
The results of human impact — deforestation, erosion, mining, and the replacement of the natural plant and animal ecology with the managed crops and domestic animals of mixed-farming life — are visible everywhere, yet certainly exaggerated. Holocene erosion-deposits in valleys and plains are actually of smaller scale and extent than Ice Age predecessors. Coastal change in historic times may seem dramatic but is as much the consequence of global sea level fluctuations (a natural result of the glacial-interglacial cycle), as of human deforestation and associated soil loss in the hinterland (Bintliff 2000, 2002). (In Figure 1.2, the largest exposures of the combined Pleistocene and Holocene river and slope deposits are grouped as Alluvium.)
Globally, at the end of the last Ice Age, sea level rose rapidly from 130 meters below present, reflecting swift melting (eustatic effects) of the major ice-sheets (Roberts 1998). By mid-Holocene times, ca. 4000 BC, when the Earth’s warming reached its natural Interglacial peak, sea levels were above present. Subsequently they lowered, but by some meters only. However, due to a massive and slower response of landmass readjustments to the weight of former ice-sheets, large parts of the globe saw vertical land and continental-shelf movements (isostatic effects), which have created a relative and continuing sea level rise, though again just a few meters. The Aegean is an area where such landmass sinking has occurred in recent millennia (Lambeck 1996). The Aegean scenario is: large areas of former dry land were lost to rising seas in Early to Mid-Holocene, 10,000-4000 BC, depriving human populations of major areas of hunting and gathering (Sampson 2006). Subsequently Aegean sea levels have risen slightly (around a meter per millennium), but remained within a few meters of the 4000 BC height, allowing river deposits to infill coastal bays and landlock prehistoric and historic maritime sites.
Let me try to give you the “feel” of the threedimensional Greek landscape. From a sea dotted with islands, the rocky peaks of submerged mountains (Color Plate 1.2a), and occasional volcanoes, the Greek coastlands alternate between gently sloping plains of Holocene and Pleistocene sediments, and cliffs of soft-sediment Tertiary hill land or hard rock limestone ridges. The coastal plains and those further inland are a combination of younger, often marshy alluvial and lagoonal sediments (usually brown hues) (Color Plate 1.2b), and drier older Pleistocene alluvial and colluvial sediments (often red hues) (Color Plate 1.3a). The coastal and hinterland plains and coastal cliff-ridges rise into intermediate terrain, hill country. In the South and East of Greece this is mainly Tertiary yellowy-white marine and freshwater sediments, forming rolling, fertile agricultural land (Color Plate 1.3b), but in the Northwest Mainland hard limestones dominate the plain and valley edges, a harsh landscape suiting extensive grazing. A compensation in hard limestone zones within this hill land, including the Northwest, is exposures of flysch, which vary from fertile arable to a coarse facies prone to unstable “badland” topography. As we move upwards and further inland, our composite Greek landscape is dominated by forbidding ridges of Alpine limestone (Color Plate 1.3a), sometimes transformed by subterranean geological processes into dense marbles. Frequently at the interface between hill land and mountain altitudes occur much older rocks: tectonic folding and faulting after the Alpine mountain-building phase has tipped up the original limestone terrain, bringing to light earlier geological formations of the Palaeozoic or preAlpine Mesozoic eras. They were joined by postOrogeny localized eruptive deposits. These are dense crystalline rocks such as schists, slates, and serpentines, whose bright colors and sharp edges trace the borders between the towering grey masses of limestone and the gentler hill lands of Tertiary sandstones or flysch which make up much of the Greek intermediate elevations. The intervention of such impermeable rocks even as thin bands at the foot of limestone massifs commonly forms a spring-line, neatly lying between good arable below and good grazing land above, a prime location for human settlement. The recent volcanic deposits can be fertile arable land, if sufficient rainfall frees their rich minerals to support soil development and plant growth. Finally, in some regions of Greece, mainly the Northeast Mainland, the Orogeny played a limited role, and the mountain massifs are much older dense crystalline rocks.
World History
