«Unità del Lucomagno»
Back to Lucomagno UnitRepresentation and status
- Color CMYK
- N/A
- Color RGB
- R: 241 G: 239 B: 237
- Rank
- nappe
- Validity
- Unit is in Use
- Status
- informal term
- Status discussion
Nomenclature
- Deutsch
- «Lucomagno-Einheit»
- Français
- «Unité du Lukmanier»
- Italiano
- «Unità del Lucomagno»
- English
- «Lucomagno Unit»
- Origin of the Name
- Historical Variants
-
Lucomagnomassiv (Jenny et al. 1923), Lucomagnodecke (Bosshard 1925), Lucomagno-Decke (Gansser & Dal Vesco 1964), Ricoprimento Lucomagno (Bianconi 1971), Lucomagno-Masse (Büchi & Trümpy 1976), falda del Lucomagno, Lucomagno unit (Böhm et al. 1996), Lucomagno Nappe (Berger et al. 2017)
Description
- Description
-
Involucro paragneissico a misto della falda Leventina-Lucomagno (metapelitischer Paragneis, gebänderter Gneis, Augengneis).
Hierarchy and sequence
- Subordinate units
Age
- Age at top
-
- Mesozoic
- Age at base
-
- Precambrian
Palaenography and tectonic
- Paleogeography
- European continental plate
- Tectonic unit (resp. main category)
References
- Definition
-
2024) :
Tectonic Map of Switzerland 1:500000, Explanatory notes. Federal Office of Topography swisstopo, Wabern
(
p.50: The Leventina-Lucomagno Nappe is the lowest unit of the Ticino Culmination. The lower part of the nappe (“Leventina Unit”) is made up of several orthogneisses forming a deformed Late Variscan magmatic edifice composed of several magmatic pulses. Along the northeastern flank of the Valle Leventina, the Leventina orthogneisses are covered by a thick stack of paragneisses and micaschists (“Lucomagno Unit”). Along this boundary, sparse quartzitic gneisses (“roof quartzites”) were interpreted as being Mesozoic in age by several authors and hence used to discriminate between a “Leventina Nappe” and a “Lucomagno Nappe”. However, these quartz-rich horizons above the orthogneisses form metasomatically altered zones – in places sheared – and cannot be considered as Mesozoic metasediments (Rütti et al. 2005; see Fig. 7). The “Lucomagno Unit” can therefore be regarded as a pre-Alpine sedimentary shell of the Leventina magmatic edifice deformed during the Alpine orogeny. Quartzitic horizons, similar to those mentioned above, also occur where the Simano Nappe directly overlies the Leventina orthogneisses. The northern part of this nappe contact is often characterized by a mylonitic band (Rütti et al. 2005 and ref. therein). To the south, this mylonitic shear zone dissipates within the Leventina orthogneisses in an anastomosing network of shear bands (Fig. 7). There, the upper limit of the Leventina-Lucomagno Nappe is difficult to trace since paragneiss and calcsilicate lenses – traditionally used to trace the tectonic contact – are in fact deformed xenoliths within the Leventina orthogneisses.
Remnants of Triassic rocks crop out around the frontal part of the Leventina-Lucomagno Nappe, although for some of them it is not clear whether they belong to the Leventina-Lucomagno Nappe or to the adjacent units. Permo-Triassic metasediments crop out also within the Leventina-Lucomagno Nappe, likely as pinched synclines (e.g., Molare Syncline; see Fig. 7) or as intranappe slices.
-
zona del (Pizzo) Molare
- Name Origin
- Rank
- tectonic zone
- Status
- informal term
- Nomenclatorial Remarks
- <p>Jeannet ----, Alb. Heim 1922</p>
- In short
-
Mesozoische Sedimentbedeckung der Lukmanier-Decke: Trias, Bündnerschiefer.
- Age
- Triassic
-
Cristallino di Prato-Cornone
- Name Origin
- Rank
- tectonically bounded lithostratigraphic unit
- Status
- informal term
- In short
-
Cristallino della falda Lucomagno: paragneiss scistoso leuco-mesocratico a grana fine, ricco di quarzo, a plagioclasio, due miche, o a biotite, e granato, con marcata tessitura planare-tabulare.