Val Vedello

For a long time we feel necessity for a quality change of Orobic Alps Geology that is not tied to hold ideas and models.

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The "Orobic Line" - "Linea Orobica"

to go into geologic questions

The” Orobic Line” -  A big  blunder of the  italian geology

The Official Geology, currently intends for “Orobic Line”,  a big  regional fault (so it is represented in the official  tectonic sketch map)  that it interests the northern part of  the Orobic Alps ( Central South Alpine Belt).

The “Orobic Line” is - more or less-  constituted by two parts direct E-W; the first  is placed  in the northeastern portion of the Orobic Alps and a second, positioned in the western south portion  - among them connected by an oblique part (see fig. 1).


fig.1

 

The dipping of this tectonic structure  is generally toward  N or toward NW. The "Orobic Line" is considered a reverse fault that it brings the most ancient rocks of the metamorphic basement to overthrusting on those more recent Permo - Triassic. The origin of this fault would be to count to the Alpine orogenesis.

Officially it is represented on the regional tectonic sketch map as a well precise line (fig.1,2,3) but sometimes described,  to according to of the convenience as a bundle of faults (from the thickness ever clarified). For this motive all the reverse faults E- W direct on the Paleozoic context of the Orobic Alps  would belong to the “Orobic Line” or-  in the best of the hypotheses- vicariant to it. The concept openly opposes with the graphic representation of an only line, topographically  perfectly located.

 

fig. 2- Particular of tectonic map  drawn by tectonic skech map  of the (1970) Geological map N° 7-18, Pizzo Bernina - Sondrio. 1:100.000 of the Geologic Maps  of Italy.  In the square it is suitable the studied area.The  Alpine oblique fault that delimits metamorphic  basement from the Permian coverage is in  reality  an extensive half graben permian fault
East, East-SudEst dipping. The  "Orobic Line" so represented it doesn't exist.

 

fig. 3- Particular of geological map drawn by a 1970 Geologic Map of the Sondrio Province -(Sondrio Province  Edition). Also this made the same interpretative error representing to the formational boundary an Alpine reverse fault  that doesn't  exist  for justifying the "Orobic  Line". In  reality to the formational boundary exists a Paleozoic extensive fault that dipping  toward East, East-SudEst. Exactly the opposed from how much represented.


The Alpine oblique fault part (in squares) that delimits metamorphic  basement from the Permian coverage is in  reality  an extensive half graben Permian fault East, East-SudEst dipping. The  "Orobic Line" so represented it doesn't exist.           

In the examination area the oblique part of the “Orobic Line” has been gotten effecting a horrendous marriage among extensive Permian  faults and portions of E-W  Alpine reverse faults.