features. There are three main geographical subdivisions: the Highlands and Islands is a diverse area which lies to the north and west of the Highland Boundary Fault; the Central Lowlands is a rift valley mainly comprising Paleozoic formations; and the Southern Uplands, which lie south of a second fault line, are largely composed of Silurian deposits. The existing bedrock includes very ancient Archean gneiss, metamorphic beds interspersed with granite intrusions created during the Caledonian mountain building period (the Caledonian orogeny), commercially important coal, oil and iron bearing carboniferous deposits and the remains of substantial tertiary volcanoes. During their formation, tectonic movements created climatic conditions ranging from polar to desert to tropical and a resultant diversity of fossil remains.
ka “vulkaane”, mida nimetatakse mustadeks suitsetajateks. Musta suitsetaja korstnast paiskub välja keemilisi aineid, näiteks H2, H2S, Fe-sulfiidi, metaani jne. On arvatud, et elu võis Maal tekkida ka sellistes tingimustes. Mikroobid on elanud mustade suitsetajate kooslustes juba vähemalt 3.3 miljardit aastat. Westall, F. et al. (2015) Archean (3.33 Ga) microbe-sediment systems were diverse and flourished in a hydrothermal context. Geology 43, 615–618 http://www.youtube.com/watch?v=rFHtVRKoaUM Mikrobioloogia I 2017
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