G e o l o g y
The Carpathians are part of the Alpine-Himalayan chain, formed
only about 35 million years ago in the Tertiary alpine orogeny,
but there is as yet no explanation for the S-shape of the Carpathian-Balkan
system. The Carpathian system is as long as the Alps (1.300 Km,
but with its ends on the Danube, at Bratislava and the Iron Gates,
only 500 Km apart) but only half their height, making it easier
to cross. The system underwent Quaternary glaciation only in the
Karkonosze, Tatras, Rodnas and the southern Carpathians. The far
older and lower remnants of the Hercynian mountains lie parallel
to the north, runing from the Vosges via the Ardennes, the Black
Forest and southern Poland to northern Dobrogea on Romania's Black
Sea coast. For the most part the Carpathians are 35-40 Km wide (double
that in the Paring area and three times that in the Rodnas) and
generally consists of three distinct bands with Flysch (or tubidite)
sediments on the outside, young crystalline massifs in the centre
in some volcanic intrusions on the inner side.
The chain is divided into four sections, of which the third and
fourth (starting from the west) are in Romania.
So the northern limit of the Romanian Carpathians is the Tisa river.
From here almost to Brasov the mountains consist of parallel ridges
of sedimentary rocks (sandstone and conglomerates) to the east ,
a central crystalline schist zone with some resistant limestones,
and to the west an inner zone of volcanic material. Between the
crystalline and volcanic zones are eight major basins filled with
fertile loess and alluvium, such as those around Miercurea Ciuc
and Targu Secuiesc.
The southern Carpathians go from Brasov all the way to the Iron
Gates. Like the Alps, this section underwent intense folding, followed
by three phases, including glaciation, that left platforms of meadow
mostly to the west of the Olt Valley. The Fagaras and Retezat massifs
are mainly hard crystalline rocks, and there are various areas of
karstic limestone. Here are reached the highest peaks in Moldoveanu
(2.544 m) and Negoiu (2.535 m). To the west, the Banat mountains
are largely sedimentary, with beds of coal around Anina.
In addition the Apuseni (Western) mountains (including the Bihor
massif) block off the Transylvanian basin to the west, forming a
rather awkward spur to the north of the main Carpathian chain. They
consist of ancient crystalline rocks, Paleozoic and Mesozoic sediments
and recent volcanic material, and are a very complex area of irregular
depressions and stranded massifs with meadow platforms or suspended
plains. There was erosion but no glaciation in the Quaternary, producing
peri-glacial forms. Above all, this is the main karst zone of Romania,
producing many gorges, caves and potholes, while tertiary eruptive
forms give a haystack form to the Muntii Metaliferi (Metal-bearing
Mountains), where gold, silver and mercury have been mined for nearly
2000 years.
Also in Romania, although not part of the Carpathian system, you'll
come across references to the following areas:
- The Transylvanian basin - undulating
hills of highly fertile Tertiary sediments such as clays,
sandstone and loess. The lowest areas such as the Barsa country
around Brasov and the Fagaras deperssion did not drain until the
Quaternary era, and there are still some peat marshes as a result.
- The Sub-Carpathians or outer foothills of
the Carpathians - mostly folded Tertiary sediments, with oil in
Pliocene formations to the north of Bucharest.
- The Romanian lowlands - formed of loess
east of the Olt River, and of sand to the west. This is covered
with cernoziom (chernozem) or black-earth soils forming very
fertile agricultural land.
- The northern Dobrogea forms the end of the worn-down Hercynian
chain, with granite, limestone and schists dating from the Primary era, some of the oldest rocks in Europe, while immediately to
the north the youngest land in Europe is still being formed in
the Danube Delta.
