Geology Flashcards
What is it loess soil present in the Danube district?
Loess is an unstratified, geologically recent, periglacial or aeolian (windborne) deposit of silty or loamy material that is usually buff or yellowish brown in colour and is chiefly deposited by the wind in form of dust. Loess is a sedimentary deposit composed largely of silt-size grains that are loosely cemented by calcium carbonate (defined as an accumulation of 20% or less of clay with a balance of roughly equal parts sand and silt -with a typical grain size from 20 to 50 micrometers-). It is usually homogeneous and highly porous and is traversed by vertical capillaries that permit the sediment to fracture and form vertical bluffs. The word loess, with connotations of origin by wind-deposited accumulation, is of German origin and means “loose.” (It was first applied to Rhine River valley loess about 1821).
Which are the mainly geological areas which characterised Austria in its major units?
Which are the typology of soils associated with?
The scenic landscape of Austria has been significantly shaped by the 4 main geological units:
• Bohemian Massif: to the north, consists of crystalline rocks of Proterozoic and Paleozoic age (consolidated, old soils, the first older than 541 million years, the latter 541-253 million years).
• Alpine Foreland: including Vienna Basin, Styrian Basin and the Pannonian Basin, recent, unconsolidated rock deposits of the Cenozoic (Neogene) up to 2,6 million years ago. It consists on Molasse soil, which is the result of the post-collision orogenic clastics when the Adriatic and the Eurasian Plates encounter each other.
• Eastern Alps: based on consolidated rocks derived from an ocean that existed in Mesozoic and early Cenozoic time (respectively, 253-66 million, until today), it present the Penninic Flysch (sequence of sedimentary rock layers -tectofacies- made up of lutite and turbidite sandstone, and rhythmite) Zone, which results from the pre-collision to syn-collisionorogenic clastics tectonic Plates meeting.
• Southern Alps: consolidated rocks which form the South Alpine Superunit.
What is it Flysch present in the Eastern Alps geological units?
Which is the difference with the Molasse present in the Alpine Foreland?
Flysch is a powerful massive sedimentary rock formations (tectofacies) made up of lutite and turbidite sandstone rhythmite deposited on continental boundaries in orogenic regions before they become deformed.
The difference is in the fact that while Flysch can be called pre-collision to syn-collision orogenic clastics, Molasse instead can be called post-collision orogenic clastics.
Which are the three major rock groups of Austria?
There are three superordinate groups of rock differentiated by geology:
• solidification rocks or igneous rocks occur as intrusive rocks (plutonic rock) or as extrusive rocks (volcanic ones);
• deposits or sedimentary rocks;
• alteration or metamorphic rocks.
Which are the common minerals present in the three major Austria’s rock groups?
• Igneous rocks: quartz, feldspar, mica, pyroxene, amphibole, olivine.
• Sedimentary rocks: quartz, clay minerals, feldspar, calcite, dolomite.
• Metamorphic rocks: quartz, feldspar, mica, garnet, staurolite, kyanite.
Basically, which are the principal geology (soil composition) of the most important wine growing regions of Austria?
• Niederösterreich: crystalline stone terraces (igneous and metamorphic rocks) or vast layers of loess (sedimentary deposit).
• Nordburgenland and Südsteiermark: calcareous soils.
• Kamptal and Vulkanland Steiermark: volcanic (extrusive igneous or solidified rocks).
Making a resume, which are the prevalent soils in Niederösterreich (Lower Austria), Burgenland and Steiermark (Styria)?
• Niederösterreich: thick loess over gneiss;
• Burgenland: sand over limestone;
• Styria: clay over limestone.
Which is the peculiarity of the geology found in the Niederösterreich?
Austrian descriptions of some Niederösterreich vineyard soils may refer to Urgestein, usually translated as ‘primary rock’, a term and a concept long obsolete in geology. It is used in Austria for relatively old, tough rocks such as granite and gneiss, which contrast with younger, softer materials such as loess (also common) and alluvium.
