Editing Harz (section)

=== Origins ===
{{See also|Harz granite}}
[[File:GabbroSteinbruchHarzburg.jpg|thumb|Gabbro Quarry near [[Bad Harzburg]]]]
The Harz is the most [[geologically]] diverse of the German ''[[Mittelgebirge]]'', although it is overwhelmingly dominated by [[base-poor]] rocks. The most common rocks lying on the surface are argillaceous [[shale]]s, slaty (''geschieferte'') [[greywacke]]s and [[granite]] intrusions in the shape of two large igneous rock masses or [[plutons]]. The Gießen-Harz surface layer of the [[Rhenohercynian zone]], which is widespread in the Harz, consists mainly of [[flysch]]. Well-known and economically important are the [[limestone]] deposits around Elbingerode and the [[Gabbro]] of [[Bad Harzburg]]. The landscapes of the Harz are characterised by steep mountain ridges, [[stone run]]s, relatively flat [[plateaus]] with many [[raised bog]]s and long, narrow [[V-shaped valley]]s, of which the [[Bode Gorge]], the [[Oker]] and [[Selke (river)|Selke]] valleys are the best known. A representative cross-section of all the Harz rocks is displayed on the Jordanshöhe near [[Sankt Andreasberg]] near the car park (see photo).

The formation and [[Orogeny|geological folding]] of the Harz hills began during a prominent phase of the [[Palaeozoic]] era, in the course of the [[Hercynian orogeny|Hercynian mountain building]] of the [[Carboniferous period]], about 350 to 250 million years ago. At that time in the [[history of the Earth]], numerous high mountains appeared in Western Europe, including the [[Fichtel Mountains]] and [[Rhenish Massif]]. They were, however, heavily eroded due to their height (up to 4&nbsp;km) and were later covered over by [[Mesozoic]] rocks. From the [[Early Cretaceous]] and into [[Late Cretaceous]] times the Harz was uplifted in a single block by [[tectonic]] movements and, particularly during the [[Tertiary]] period, the younger overlying strata were eroded and the underlying base rock left standing as low mountains. The most important uplift movements were during the sub-Hercynian phase (83&nbsp;[[mya (unit)|mya]]), when the northern edge was steeply tilted. This formed a fault zone on the northern border of the Harz (the [[Northern Harz Boundary Fault]] or ''Harznordrandverwerfung'').

The Harz is a [[fault-block]] range, that rises abruptly from the surrounding lowlands in the west and northeast and gradually dips towards the south. It is dissected by numerous deep valleys. North of the hills lie the Cretaceous layers of the sub-Hercynian depression in the rolling hills of the Harz Foreland; south of the Harz, [[Permian]] sediments lie flat on southwest-dipping Palaeozoic beds.

As a result of the northern fault zone and the vertical or, sometimes even overfolded, geological strata, the geology of the Harz sometimes changes frequently within a relatively small area of just a few square kilometres. As a consequence of this it is also referred to as the "Classic Geological Square Mile" (''Klassischen Quadratmeile der Geologie'').

There is a room devoted to geology in the Harz Museum in Wernigerode.