Why is ESAC so hilly?

A talk (Thursday, December 1st) and a fieldtrip (Friday, December 2nd)

Enrique Díaz Martínez Researcher of the Geological Survey of Spain (IGME)

Why is ESAC so hilly?

Geology of the Madrid region

ESAC talk on the geology of Madrid 01-12-2016

FIRST GEOLOGY MAPS OF THE PROVINCE OF MADRID 1853 (“bosquejo” or sketch), 1861 and 1864

Casiano de Prado y Valle (1797 – 1866)


Geological map of the province of Madrid (currently as “Autonomous Community”)

A geological map shows the composition (lithology), age and structure of the rocks Geological time is measured in millions of years


The geological clock (1 h = 4.600 Ma)












Geological units of Madrid: - Guadarrama and Somosierra ranges (Central System), Paleozoic and Mesozoic age - Madrid Basin (part of Tajo sedimentary basin), Cenozoic age (Tertiary) - Fluvial valleys (Alberche, Jarama, Henares, Tajo, etc.), Quaternary age

Geological map of the province of Madrid


The Central System:

Variscan orogeny

<= Granites

(Siete Picos, La Pedriza, La Cabrera) <= Quartzites, slates (Puebla de La Sierra) <= Gneises (La Morcuera, El Vellón)



Long period without geological record. The Variscan Mountains were intensely eroded.

Alpine orogeny <= Gypsum and red clays (Torrelaguna) <= Marine limestones (Guadalix, Patones)

The Central System:

Variscan orogeny

<= Granites

(Siete Picos, La Pedriza, La Cabrera) <= Quartzites, slates (Puebla de La Sierra) <= Gneises (La Morcuera, El Vellón)



GEOLOGICAL CROSS SECTION OF THE CENTRAL SYSTEM


THE BASIN:


- Lacustrine limestones (Chinchón, Colmenar de Oreja)

-  Marls and gypsum (La Poveda, and Ciempozuelos cliffs)

-  Sands and gravels (El Pardo, Majadahonda, Tres Cantos)

THE BASIN:

Alpine orogeny

<= Gypsum and red clays (Torrelaguna)


Author: Mauricio Antón (MNCN)

Scene recreating the environment deduced from the Miocene fossil site of the M-30 (Casa de Campo, Madrid)



Scene recreating the environment deduced from the Miocene fossil site of the “Hidroléctrica” (Paseo de la Virgen del Puerto, Madrid)



Scene recreating the environment deduced from the Miocene fossil site of the Cerro Batallones (Torrejón de Velasco, Madrid)


Atapuerca family picture. Author: Mauricio Antón (MNCN)

Period Epoch

Quaternary (2.6 Ma - today)

Holocene (11,000 a - today)

Pleistocene (2.6 Ma – 11,000 a)


THE VALLEYS:

Epoch




<= Modern alluvial deposits (flood plains)

<= Fluvial terrace deposits (sands and gravels)

THE VALLEYS:

Epoch




And also… glaciers!

Glacial evolution of the Peñalara massif Author: Eduardo Acaso

Epoch





So… What will we see

tomorrow?



GRANITES

- Geological setting

-  Plutonic rocks (magma “frozen” underground), silica-rich (acid) composed of quartz, K-feldspar, plagioclase and biotite, plus local moscovite, amphiboles, cordierite, etc.

-  Types: leucogranites vs monzogranites, porphyritic vs equigranular, coarse vs fine…


Type of textures in different rocks of granitic composition

Rock: Granite Granite porphyry Aplite Pegmatite Obsidian

Type of texture: Granitic Porphyritic Aplitic Pegmatitic Vitreous

Size of crystals: All average Some large and some small All small All large No crystals (just glass)

How did the rock form?

Many crystals grew slowly

A few crystals grew slowly, then the rest grew quickly

Many crystals grew quickly

A few crystals grew slowly

Rapid cooling inhibits cristal growth


GRANITIC MASSIFS

-  Geological setting

-  Lithology (different compositions)

- Fracturing of rocks

- Climate and erosion


Come to the field with us tomorrow!!

Thank you very much for your attention.

…and don’t forget to visit our museum at

Ríos Rosas, 23 (Madrid)

Why is ESAC so hilly?

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