GlossaryPrint

Pacific Ocean

the largest ocean, with 49% of all oceanic waters, occupying about 165 million km2 and with an average depth of 4188 m.

Paleocene (65-56 Ma)

first Epoch of the Paleogene Period meaning 'old-new'. Little evolved mammal faunas appear, that developed after the extinction of dinosaurs. Gondwana continued to break-up and Africa, South America, Antarctica and Australia drifting apart. Important volcanic eruptions occurred in the beginning of the Paleocene, in the land mass corresponding to present-day India, leading to the accumulation of thick lava layers in the Deccan plateau.

Paleoclimate

concerning the study of past climate.

Paleoenvironment

concerning the study of past environment.

Paleogene (65-23 Ma)

period of the Cenozoic Era marked by the expansion of mammals. During this period North America, Greenland and Great Britain were linked; India was not yet joint to Asia and the Indian Ocean continued to expand. A cooling of the planet continued which led to an increase of the volume of ice at the poles (Eocene) and the installation of a layer of cold water in the bottom of the current oceans. There was a great development of mammals (Paleocene), and new species appeared (carnivores, rodents and primates).

Paleogondwana

super-continent formed during the Precambrian, after the separation of Paleolaurentia, Baltica and Siberia.

Paleolaurentia

continent formed in the beginning of the Paleozoic by the land masses that correspond to present-day North America and Greenland.

Paleotethys

old Paleozoic ocean that bathed, to the east, ancient Siberia and Baltica.

Paleozoic Era or Paleozoic (542-251 Ma)

meaning 'ancient life'. It is the first of the three major geological Eras. It begins with a major explosion in life forms and ends with the largest known mass extinction (about 90% of marine species did not survive), as the result of a number of extreme events, such as the fall of many meteorites, intense volcanic and tectonic activity, leading to a drastic climate change. During this Era, consisting of six periods (Cambrian, Ordovician, Silurian, Devonian, Carboniferous and Permian), the planet experienced huge modifications with the joining of almost all the land then emerged in a single super-continent (the Pangea).

Pangea

the term means 'all the lands'. Super-continent formed at the end of the Paleozoic Era, resulting from the joining of all the emerged lands existent at that time.

Pannotia

super-continent formed in the upper Precambrian, bathed by Panthalassa, which will break apart later, leading to the formation of the Iapetus Ocean.

Panthalassa

vast global ocean that surrounded the supercontinent Pangea, during the Paleozoic and the beginning of the Mesozoic. The term means 'all the seas'.

Pebble tool

pebble shaped into a tool, comprising a working edge partially produced by the knapping of one face (single face knapped pebble - Chopper) or alternatively on the two faces (bifacial knapped pebble – Chopping tool) of a blank.

 

Permanent crops

crops that occupy the land for a long time and provide repeated harvests, not needing planting rotations. Permanent meadows and pastures are excluded.

Permanent grassland and meadow

sowed or spontaneous, usually herbaceous plants for livestock to eat at the site where they grow but that can also be cut at certain times of the year. Not included in rotation and occupy the land for more than five years.

Permian (299-251 Ma)

period of the Paleozoic Era, with intense tectonic activity (Hercinian orogeny), resulting from the collision of continents that would form Pangea. The biggest known life form extinction happened at the end of this period.

Photovoltaic energy

energy produced by the use of direct or indirect sunlight, through panels of photovoltaic cells able to transform light energy into electrical energy.

Plagioclase

mineral composed by aluminum, sodium and calcium silicates. It is common in magmatic rocks.

Plateau

form of relief, at high altitudes, which presents a flat or slightly wavy topographic surface due to the action of erosive agents (wind and water), over geologic time.

 

Plateosaurus

quadruped herbivore dinosaur (sometimes biped) that lived during the Upper Triassic (228200 Ma). It was approximately 8 m long and weighed about 1.8 tons.

Pleistocene (2.5-0.012 Ma)

subdivision of the last geological era of our planet - the Quaternary. It is subdivided by convention into three periods: the Lower Pleistocene (2.5 million – 700,000 years), the Middle Pleistocene (700,000 – 128,000 years) and the Upper Pleistocene (128,000 – 12,000 years BP). Its lower limit does not have a well-defined dating because of the absence of fossils, and it corresponds to the last interval of the Earth’s history, marked by consecutive glaciations. The evolution of Anatomical Modern Human occurred during this period (at approximately 150 000 years). Due to huge climatic variations, there are changes in the fauna and flora. Many extinction episodes occur, as is the case of the larger mammals (mammoths, mastodons, saber-tooth tigers, among others).

 

Plesiadapis

small prehistoric mammal, extinct today, about 80 cm long, similar to the present squirrels and that fed on fruit, leaves and maybe insects. It lived from the Paleocene to the end of the Eocene (66-34 Ma).

Pliocene (5-2.5 Ma)

geological epoch prior to the Quaternary. The fauna and flora were similar to present-day ones, but with a different geographical distribution. The continents practically had the present configuration, with the exception of the South and North Americas that joined in the upper Pliocene, allowing huge mammal migrations between the two continents. During this time there was a cooling of the planet that became dryer, causing a considerable change in the vegetation, reducing forest areas and making savannas and deserts appear. At the end of the Pliocene a large part of the big mammals disappeared, appearing the Equus and the Elephas and the expansion of hominids begins.

Plutonic rock

formed at great depths, when slow cooling of magma produces large minerals. Very abundant rocks in nature; found in Portugal especially in the centre and north of the country. Used since prehistoric times, for example in the construction of dolmens, or later in some Roman milestones, and now as ornamental rocks in the façades of buildings.

Point

very broad term covering any artifact made from a flake or blade, with a pointed morphology, comprising two converging edges, generated or not by retouch.

 

Population density

ratio between the number of inhabitants occupying a certain area and the size of this area (usually expressed in number of inhabitants per square kilometre). The calculation formula is “total number of individuals / area * 100” and the unit of measurement is “number / square kilometre (N.º/ km²)”.

Precambrian (~4 600-542 Ma)

very long time-period in the history of the Earth, since it's beginning until the Paleozoic Era. During this period the first life forms appeared, of which stand out the photosynthetic organisms, capable of producing oxygen, and that changed the atmosphere’s chemistry, by removing the carbon dioxide, allowing the appearance of superior organisms. In the end of this period, the Earth was composed by a super-continent, Pannotia, that combined all the emerged lands, and by a global ocean, Panthalassa.

Proboscid

large placental herbivore mammal, which belongs to the order Proboscidae. Appears in the lower Eocene (40 Ma) and was very abundant (fossil record of about 170 species, including the mammoths and mastodons). Currently there are only 3 species of proboscidea: 2 African elephants and 1 Asian elephant. It is characterized by the presence of a nose developed in the shape of a trunk.

Production mode

concept that intends to summarise the variability that existed in prehistoric stone industries, irrespective of the time and space in which such industries occurred. Each industry is grouped into entities (production modes) sharing certain technological and typological characteristics.

 

Protected Area

well-defined area established and managed as to maintain the existing natural and cultural values. To create a Protected Area, studies are made and the community, various entities, and organizations are consulted. In these areas, several rules must be respected as to protect nature and improve quality of life. Protected areas can be: National Park, Natural Reserve, Natural Park and Natural Monument, Protected Landscape, Site of Biological Interest.

Protected Geographical Indication

name, recognised at the national and EU level, of a region, a particular place or, exceptionally, a country. The geographical indication designates an agricultural product or foodstuff from that region, place or country whose reputation, quality or other characteristic are attributed to this geographical origin and whose production, manufacture or preparation occurs in the delimited geographical area.

Protected landscape

protected area of regional or local interest managed by municipalities. It has natural, semi-natural and humanised landscapes as the result of a harmonious action between people and nature.

Pyroxene

anhydrous silicate mineral usually dark in colour. It is very common in volcanic rocks.

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