Messinian or Pleistocene valley incision within the Southern Alps
Abstract Many of the valleys on the southern slope of the Alps are over-deepened, having bedrock valley floors well below sea level. This has typically been attributed to incision that occurred during the Messinian Salinity Crisis (MSC) when sea level dropped by hundreds of meters, leading to incisi...
| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
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SpringerOpen
2020-06-01
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| Series: | Swiss Journal of Geosciences |
| Subjects: | |
| Online Access: | https://doi.org/10.1186/s00015-020-00361-7 |
| _version_ | 1819100711021969408 |
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| author | Sascha Winterberg Vincenzo Picotti Sean D. Willett |
| author_facet | Sascha Winterberg Vincenzo Picotti Sean D. Willett |
| author_sort | Sascha Winterberg |
| collection | DOAJ |
| description | Abstract Many of the valleys on the southern slope of the Alps are over-deepened, having bedrock valley floors well below sea level. This has typically been attributed to incision that occurred during the Messinian Salinity Crisis (MSC) when sea level dropped by hundreds of meters, leading to incision of many of the margins of the Mediterranean. We reassess this interpretation by documenting the correct elevation of the valley floor of the Adige river, one of the major valleys draining the Southern Alps, and by estimating the vertical motion of that valley floor since the end of Messinian incision. We re-evaluated the bedrock incision in the Adige valley using existing borehole data and seismic profiles. We estimate the vertical post-Messinian uplift using thermochronometric data that reveal the removed rock mass and then infer the expected isostatic uplift. These data are combined to reconstruct paleo-river gradients and to test viability of incision profiles. We find that the erosive surfaces in the drill holes restore to a paleo-elevation well below estimates of the Messinian Salinity Crisis (MSC) sea level. Restored valley gradients are often reversed compared to todays river gradients, as the uplift correction is higher upstream. A Messinian age of the erosional unconformities within the Alps can therefore be excluded based on the current best estimates of Messinian Mediterranean sea level and post-Messinian rock uplift. Pleistocene glacial erosion left a major signature on the geomorphology of the valleys, which is documented by glacially over-deepended valleys in the northern Alps. These valleys are not influenced by the Messinian sea-level drawdown. Therefore, it is suggested that the over-deepened valleys on the southern slope of the Alps are also glacial in origin. |
| first_indexed | 2024-12-22T01:07:07Z |
| format | Article |
| id | doaj.art-fdaa309dfaf34432b208d3ecea307e64 |
| institution | Directory Open Access Journal |
| issn | 1661-8726 1661-8734 |
| language | English |
| last_indexed | 2024-12-22T01:07:07Z |
| publishDate | 2020-06-01 |
| publisher | SpringerOpen |
| record_format | Article |
| series | Swiss Journal of Geosciences |
| spelling | doaj.art-fdaa309dfaf34432b208d3ecea307e642022-12-21T18:44:03ZengSpringerOpenSwiss Journal of Geosciences1661-87261661-87342020-06-01113111410.1186/s00015-020-00361-7Messinian or Pleistocene valley incision within the Southern AlpsSascha Winterberg0Vincenzo Picotti1Sean D. Willett2Geological Institute, ETH ZürichGeological Institute, ETH ZürichGeological Institute, ETH ZürichAbstract Many of the valleys on the southern slope of the Alps are over-deepened, having bedrock valley floors well below sea level. This has typically been attributed to incision that occurred during the Messinian Salinity Crisis (MSC) when sea level dropped by hundreds of meters, leading to incision of many of the margins of the Mediterranean. We reassess this interpretation by documenting the correct elevation of the valley floor of the Adige river, one of the major valleys draining the Southern Alps, and by estimating the vertical motion of that valley floor since the end of Messinian incision. We re-evaluated the bedrock incision in the Adige valley using existing borehole data and seismic profiles. We estimate the vertical post-Messinian uplift using thermochronometric data that reveal the removed rock mass and then infer the expected isostatic uplift. These data are combined to reconstruct paleo-river gradients and to test viability of incision profiles. We find that the erosive surfaces in the drill holes restore to a paleo-elevation well below estimates of the Messinian Salinity Crisis (MSC) sea level. Restored valley gradients are often reversed compared to todays river gradients, as the uplift correction is higher upstream. A Messinian age of the erosional unconformities within the Alps can therefore be excluded based on the current best estimates of Messinian Mediterranean sea level and post-Messinian rock uplift. Pleistocene glacial erosion left a major signature on the geomorphology of the valleys, which is documented by glacially over-deepended valleys in the northern Alps. These valleys are not influenced by the Messinian sea-level drawdown. Therefore, it is suggested that the over-deepened valleys on the southern slope of the Alps are also glacial in origin.https://doi.org/10.1186/s00015-020-00361-7AlpsMessinianGlaciationErosionAdige riverIncision |
| spellingShingle | Sascha Winterberg Vincenzo Picotti Sean D. Willett Messinian or Pleistocene valley incision within the Southern Alps Swiss Journal of Geosciences Alps Messinian Glaciation Erosion Adige river Incision |
| title | Messinian or Pleistocene valley incision within the Southern Alps |
| title_full | Messinian or Pleistocene valley incision within the Southern Alps |
| title_fullStr | Messinian or Pleistocene valley incision within the Southern Alps |
| title_full_unstemmed | Messinian or Pleistocene valley incision within the Southern Alps |
| title_short | Messinian or Pleistocene valley incision within the Southern Alps |
| title_sort | messinian or pleistocene valley incision within the southern alps |
| topic | Alps Messinian Glaciation Erosion Adige river Incision |
| url | https://doi.org/10.1186/s00015-020-00361-7 |
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