Access to the Iberian peninsula is limited by mountains. One can come from Africa, across the Straits of Gibralter, as the Carthaginians did. Later, the Vandals moved down the countryside into Africa. Later still, Moslems moved north. After the reconquest, Moors and Jews moved back south to Tunis.
One can come by sea from the east, as the Phoenicians and Greeks did, or one can inch around the Pyrenees. Neanderthals living along the Mediterranean coast were related to those living in Italy and southern France. Those found from the Bay of Biscay to the Cantabrian mountains were related to those in northern Europe.
Bands reached the limestone mountain barriers on the west side of the Estremadura by 70,000 years ago during a general cold spell. The lower levels of the cave at Gruta da Oliveira on the Almonda branch of the Tagus have remains of burned small tortoises.
Tortoises were still being used 62,000 years ago, but most of the bones were from plant eating ungulates: rhinoceros, mountain goats, deer, and horses.
The climate was cold and damp. Charcoal remains came from Scots pine, a tree that can’t tolerate droughts. It eventually sought refuge near the Pyrenees.
Men had adapted. Only 50% of their tools were made from flint. The rest came from locally available quartzite and quartz.
About 55,000 years ago, the behavior of the glacier changed in the Estremadura. The climate alternated between periods of dry cold and moister warmth. During cold spells, arid steppe dominated the landscape. Dust flaked off barren uplands. Sediments covered decaying bones.
During warm times, Scots pine sometimes had time to emerge. Roots dug into the soil and erosion abated.
A few times the climate warmed enough for deciduous and evergreen oaks to return with hazel and copper beech. One time, birches appeared with aurochs. Another time, junipers and alders.
Animals and Neanderthals followed their food supply. They usually returned to Gruta da Oliveira in the warmer periods.
In the layers of the cave from 50,000 years ago, Mariana Nabais believed bones were burned for fuel because they didn’t produce smoke. Pines might not have returned. The land might still have been treeless.
In the time between 48,000 and 40,000 years ago, mountain goats were present along the Almonda. Some fragments of wood charcoal survived.
Nabais said the burned bones were again important in the occupation dated to 42,900 years ago. The climate might have warmed, but the landscape remained treeless. The most common species were rabbit and red deer. Hares and rabbits were another animal genus to survive the Pleistocene along the Portuguese coast and up the Tagus. The European rabbit would eventually emerge from there to repopulate the countryside.
Around 35,000 years ago, the climate began to warm. Forests and pigs appeared. Neanderthals ventured further into the Estremadura.
A work site has been found on a tributary of the Tagus that drew its waters from the limestone of the Gruta de Oliveira, rather than the granite of the east. Instead of ore bearing deposits, the soils around Foz do Enxarrique contain calcium carbonate that preserved bones.
Men were making tools on the gravel terrace using the quartzite and quartz. Most of the bones were red deer, but teeth of horses and aurochs have been found. Archaeologists also discovered a tooth left by a straight-tusked elephant, one of the last recorded appearances of Elephas antiquus in Europe.
The weather turned cold again around 32,700 years ago. Dry steppe dominated. The roof collapsed on the cave at Gruta da Oliveira. Mountain goats disappeared, but deer, wood mice and garden dormice remained. Species of salamanders, lizards, and frogs survived in the Estremadura.
Neanderthals moved farther south. Their last known remains, dated to 24,000 years ago, were found at Gibralter. Extreme cold arrived around 22,000 years ago and lasted nine thousand years.
Notes:
Badal, Ernestina, Valentín Villaverde, and João Zilhão. "The Fire of Iberian Neanderthals. Wood Charcoal from Three New Mousterian Sites in the Iberian Peninsula," International Meeting of Charcoal Analysis, Sagvntvm, 2011.
Cardoso, João Luís. "The Mousterian Complex in Portugal," Zephyrus 59:21-50:2006.
Gómez, Africa and David H. Lunt. "Refugia Within Refugia: Patterns of Phylogeographic Concordance in the Iberian Peninsula," in Steven Weiss and Nuno Ferrand, Phylogeography of Southern European Refugia, 2006.
Nabais, Mariana. "The Neanderthal Occupation of Gruta Da Oliveira (Almonda Karstic System, Torres Novas, Portugal)," Jóvenes En Investigación Arqueológica, Jornadas, 2009.
Notes on species: Only the genus or family could be determined for many of the animal and plant remains.
Animals Large
Auroch - Bos primigenius
Deer Red - Cervus elaphus
Elephant Straight Tusk - Elephas antiquus
Goat Mountain goat - Capra
Horse - Equus
Rhinoceros - Rhinocerotidae
Pig - Sus
Animals Small
Dormice Garden - Eliomys quercinus
Frog Iberian Painted - Discoglossus galganoi
Hares - Leporidae
Lizard Iberian Wall - Podarcis hispanica
Mice Wood - Apodemus sylvaticus
Rabbit European - Oryctolagus cuniculus
Salamander Fire - Salamandra salamandra
Tortoise Hermann’s - Testudo hermanni
Trees
Alder - Alnus
Beech Copper - Fagus sylvatica
Birch - Betula
Hazel - Corylus
Juniper - Juniperus
Oak - Quercus
Oak Evergreen - Quercus ilex
Pine Scots - Pinus sylvestris
Showing posts with label 29 Estremadura (1-5). Show all posts
Showing posts with label 29 Estremadura (1-5). Show all posts
Sunday, August 09, 2015
Sunday, March 01, 2015
Estremaduran Landscape
Physiographic maps like that posted 17 February use shades of green for low elevations and grays for higher. This gives the mistaken impression the Estremadura is a great, fertile basin. It’s not. All those mountain ranges prevent water from flowing into the area.
Badajoz gets 18.2 inches of rain a year, with most of it falling in winter. That’s more than the twelve we get here. All that granite and granite debris support thin acid soils, unlike the alkaline ones we have here.
Nature has responded to the Estremadura’s Mediterranean climate with trees that have wide branching habits, extensive root systems, and leaves that fall in summer. The one provides shade that slows evaporation. The second holds dry soil from blowing away and traps water wherever it lands. The third carpets the ground in summer, at the same time it reduces stress on defoliating plants.
At one time, the Estremadura was covered by woodland. The most common landscape today is the bosque Mediterráneo dominated by encina, live oaks (Quercus rotundifolia). Oliver Rackham says the species is so variable no two are alike genetically.
The oak survives fire and cutting. For centuries its branches were lopped in March and April and burned to make charcoal. The constant trimming increased the acorn crop that was eaten by livestock. The bark was used to tan leather.
The one thing encina doesn’t like is constant browsing. When oaks die back, the dehesa expands, with one kind of grass growing under the trees and another in the open. The primary wild plants are winter annuals that bloom in spring, purple viper’s bugloss, tolpis, andryala, corn marigold, and yellow chamomile. The first is a borage, the rest members of the composite family. The open pasture or savannah supports cattle and cereal production.
When trees are felled in large numbers, dense scrub intrudes. Brooms (Cistus), lavenders, mastics (Pistacia lentiscus), and strawberries trees (Arbutus unedo) thrive. The first are rock roses, the second mints. The third is a member of the cashew family, and the last a heather.
When that second generation protective scrub is removed, single species like brambles, heathers and gorse advance. These are more tolerant of drought, poor soils, and brush fires.
Along the mountainous perimeter, deciduous trees grow in the bosque de montaña. Melojos (Quercus pyrenaica) are most common, but there also are chestnut groves and clumps of Portuguese oak (Quercus faginea).
Near the Tagus and its more permanent tributaries riparian species grow. In the higher elevations, the bosque en galería sports willows, osiers, and alders. Aspen and ashes replace them at lower levels. In the lower bosque de ribera bushes, oleanders, tamujo brooms (Flueggea tinctoria), and vines grow under elms.
To the south, where the climate is warmer, cork oak (Quercus suber) grows in the protection of the mountain ranges. It requires more moisture than the live oak, but has a unique way of surviving fires. It grows a thicker bark than other plants.
Notes:
Grove, A. T. and Oliver Rackham. The Nature of Mediterranean Europe, 2001.
Instituto de Educación Secundaria les Dr. Fernández Santana. "Vegetation of Extremadura," school web site.S
To share information, send an email to nasonmcormic@cybermesa.com or leave a comment below. You may need to have your email application open for the direct link to work.
Badajoz gets 18.2 inches of rain a year, with most of it falling in winter. That’s more than the twelve we get here. All that granite and granite debris support thin acid soils, unlike the alkaline ones we have here.
Nature has responded to the Estremadura’s Mediterranean climate with trees that have wide branching habits, extensive root systems, and leaves that fall in summer. The one provides shade that slows evaporation. The second holds dry soil from blowing away and traps water wherever it lands. The third carpets the ground in summer, at the same time it reduces stress on defoliating plants.
At one time, the Estremadura was covered by woodland. The most common landscape today is the bosque Mediterráneo dominated by encina, live oaks (Quercus rotundifolia). Oliver Rackham says the species is so variable no two are alike genetically.
The oak survives fire and cutting. For centuries its branches were lopped in March and April and burned to make charcoal. The constant trimming increased the acorn crop that was eaten by livestock. The bark was used to tan leather.
The one thing encina doesn’t like is constant browsing. When oaks die back, the dehesa expands, with one kind of grass growing under the trees and another in the open. The primary wild plants are winter annuals that bloom in spring, purple viper’s bugloss, tolpis, andryala, corn marigold, and yellow chamomile. The first is a borage, the rest members of the composite family. The open pasture or savannah supports cattle and cereal production.
When trees are felled in large numbers, dense scrub intrudes. Brooms (Cistus), lavenders, mastics (Pistacia lentiscus), and strawberries trees (Arbutus unedo) thrive. The first are rock roses, the second mints. The third is a member of the cashew family, and the last a heather.
When that second generation protective scrub is removed, single species like brambles, heathers and gorse advance. These are more tolerant of drought, poor soils, and brush fires.
Along the mountainous perimeter, deciduous trees grow in the bosque de montaña. Melojos (Quercus pyrenaica) are most common, but there also are chestnut groves and clumps of Portuguese oak (Quercus faginea).
Near the Tagus and its more permanent tributaries riparian species grow. In the higher elevations, the bosque en galería sports willows, osiers, and alders. Aspen and ashes replace them at lower levels. In the lower bosque de ribera bushes, oleanders, tamujo brooms (Flueggea tinctoria), and vines grow under elms.
To the south, where the climate is warmer, cork oak (Quercus suber) grows in the protection of the mountain ranges. It requires more moisture than the live oak, but has a unique way of surviving fires. It grows a thicker bark than other plants.
Notes:
Grove, A. T. and Oliver Rackham. The Nature of Mediterranean Europe, 2001.
Instituto de Educación Secundaria les Dr. Fernández Santana. "Vegetation of Extremadura," school web site.S
To share information, send an email to nasonmcormic@cybermesa.com or leave a comment below. You may need to have your email application open for the direct link to work.
Sunday, February 22, 2015
Estremaduran Geohistory
The Iberian peninsula began as a terrane off the north coast of Gondwana some 650 to 550 million years ago during the Late Neoproterozoic era. The Central Iberian island arc undergirding Estremadura merged with the Ossa-Morena and South Portuguese arcs to form what is today western Spain and Portugal.
In the early Paleozoic, sometime from 542 to 488 million years ago, sediments were deposited that hardened into gneisses, schists, quartzites and slates. Volcanoes elsewhere on the planet warmed the Ordovician climate that followed. Sea life left calcium compounds that became limestones.
During the Silurian era, the united group broke away from Gondwana and joined the Amorica terrane. Over the course of millennia Amorica alternated between the northern landmass of Laurussia and the southern Gondwana until those two merged to form Pangaea in the Early Permian period, about 270 million years ago.
The collision that formed Pangaea initiated a period of mountain building. In the Estremadura, molten granite rose through limestone walls that precipitated silver, gold and tin. As they cooled, the minerals were deposited in existing veins of quartz.
About 200 million years ago, in the early Jurassic, the Pangaean supercontinent began breaking up. The Bay of Biscay opened about 126 millions years ago in the Early Cretaceous. The Iberian nucleus rotated counterclockwise to Europe and came back under the influence of Africa during the Cenozoic.
The Alps formed during the Paleocene. Oaks began to differentiate themselves within the beech family about 60 million years ago in that same epoch. They eventually became the characteristic flora of the Estremaduran region.
Tectonic movement stopped in the mid-Eocene and the Pyrenees arose. In the Late Oligocene the peninsula resumed moving with Eurasia. The Tagus basin formed from sediment eroded from the mountains. Tin, silver and gold washed downstream. Limestone now overlays ochre-colored clay and silt.
Today, the two continental plates abut each other under the Mediterranean. The Eurasian continues to pull east away from its boundary with the North American plate under the Atlantic. The African plate is moving northeast about an inch every three years. Less than nine miles separates the surfaces of the two at the Straits of Gibralter.
Judging from current seismic activity, João Duarte Fonseca believes a "continental block formed by Iberia and northern Morocco is being pushed west wards by the convergence."
Notes: João F.B. Duarte Fonseca, Seismicity and Regional Tectonics of the Estremadura, Southwestern Portugal, dissertation abstract, 1989.
In the early Paleozoic, sometime from 542 to 488 million years ago, sediments were deposited that hardened into gneisses, schists, quartzites and slates. Volcanoes elsewhere on the planet warmed the Ordovician climate that followed. Sea life left calcium compounds that became limestones.
During the Silurian era, the united group broke away from Gondwana and joined the Amorica terrane. Over the course of millennia Amorica alternated between the northern landmass of Laurussia and the southern Gondwana until those two merged to form Pangaea in the Early Permian period, about 270 million years ago.
The collision that formed Pangaea initiated a period of mountain building. In the Estremadura, molten granite rose through limestone walls that precipitated silver, gold and tin. As they cooled, the minerals were deposited in existing veins of quartz.
About 200 million years ago, in the early Jurassic, the Pangaean supercontinent began breaking up. The Bay of Biscay opened about 126 millions years ago in the Early Cretaceous. The Iberian nucleus rotated counterclockwise to Europe and came back under the influence of Africa during the Cenozoic.
The Alps formed during the Paleocene. Oaks began to differentiate themselves within the beech family about 60 million years ago in that same epoch. They eventually became the characteristic flora of the Estremaduran region.
Tectonic movement stopped in the mid-Eocene and the Pyrenees arose. In the Late Oligocene the peninsula resumed moving with Eurasia. The Tagus basin formed from sediment eroded from the mountains. Tin, silver and gold washed downstream. Limestone now overlays ochre-colored clay and silt.
Today, the two continental plates abut each other under the Mediterranean. The Eurasian continues to pull east away from its boundary with the North American plate under the Atlantic. The African plate is moving northeast about an inch every three years. Less than nine miles separates the surfaces of the two at the Straits of Gibralter.
Judging from current seismic activity, João Duarte Fonseca believes a "continental block formed by Iberia and northern Morocco is being pushed west wards by the convergence."
Notes: João F.B. Duarte Fonseca, Seismicity and Regional Tectonics of the Estremadura, Southwestern Portugal, dissertation abstract, 1989.
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