GlossaryPrint

Geometric

retouched microlith in the shape of a simple geometric figure (triangle, trapezium, segment of a circle or a rectangle).

Glacial Era or Ice Age

periods in which the Earth’s atmosphere was extremely humid, thickly covered with clouds witnessing a strong decrease in temperature. Due to these weather conditions, in regions of high latitude and altitude perpetual snow covered the land. The retention of water in these ice masses led to sea level lowering. This reduction was about 130 meters during the last glaciation (Würm glaciation), about 20 000 years ago.

Glaciation

period in which the Earth registers a strong reduction in average global temperature, leading to the increase of polar ice caps and glaciers. This retention of fresh water in cold continental areas leads to the lowering of the sea level. Glaciations are known in the Paleozoic and Cenozoic, namely in the Quaternary.

Gondwana

great continent in the Mesozoic Era, which included most of the emerged lands that presently constitute the continents of the Southern Hemisphere (Antarctica, South America, Africa, Madagascar, Seychelles, India, Australia, New Guinea, New Zealand and New Caledonia). It resulted from the fragmentation of Pangea into Laurasia in the northern hemisphere and Gondwana in the southern hemisphere.

Granite

plutonic magmatic rock, consisting mainly of quartz and feldspars (up to 85% to 95% of its composition), having as accessory minerals biotite, muscovite and amphibole, or, even, pyroxene and olivine. The texture of granite is variable, depending on the size of the minerals and their habit. It is used as ornamental stone. Nowadays, the granite is used as ornamental rock and for construction. It was used as an accumulator of heat in some Palaeolithic settlements of the Côa Valley.

 

Gravettian

technology-complex of the first part of the European Upper Paleolithic, with a broad geographic distribution, including Iberia. It develops between 28.500 e 22.000 BP.

 

Greywacke

fine-grained detrital sedimentary rock, consisting of angular to subangular quartz and feldspar grains and small fragments of dark minerals that give it a greenish to grey colour and agglutinated by a fine clay-sized matrix. Characteristic of marine environments.

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