Evidence of deep-water inflow in a tectonic window of the northern Apennines (Italy)

Abstract. Phosphorus fertilisation (eutrophication) is expanding oxygen depletion in coastal systems worldwide. Under low-oxygen bottom water conditions, phosphorus release from the sediment is elevated, which further stimulates primary production. It is commonly assumed that re-oxygenation could break this “vicious cycle” by increasing the sedimentary phosphorus retention. Recently, a deep-water inflow into the Baltic Sea created a natural in situ experiment that allowed us to investigate if temporary re-oxygenation stimulates sedimentary retention of dissolved inorganic phosphorus (DIP). Surprisingly, during this 3-year study, we observed a transient but considerable increase, rather than a decrease, in the sediment efflux of DIP and other dissolved biogenic compounds. This suggested that the oxygenated inflow elevated the organic matter degradation in the sediment, likely due to an increase in organic matter supply to the deeper basins, potentially combined with a transient stimulation of the mineralisation efficiency. As a result, the net sedimentary DIP release per m2 was 56 %–112 % higher over the years following the re-oxygenation than before. In contrast to previous assumptions, our results show that inflows of oxygenated water to anoxic bottom waters can increase the sedimentary phosphorus release.

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Origin and assessment of deep groundwater inflow in the Ca' Lita landslide using hydrochemistry and in situ monitoring

Hydrology and Earth System Sciences ◽

10.5194/hess-16-4205-2012 ◽

2012 ◽

Vol 16 (11) ◽

pp. 4205-4221 ◽

Cited By ~ 18

Author(s):

F. Cervi ◽

F. Ronchetti ◽

G. Martinelli ◽

T. A. Bogaard ◽

A. Corsini

Keyword(s):

Groundwater Flow ◽

Deep Water ◽

Major Ions ◽

Pore Water Pressure ◽

Water Pressure ◽

Slope Instability ◽

In Situ Monitoring ◽

Water Inflow ◽

Groundwater Levels

Abstract. Changes in soil water content, groundwater flow and a rise in pore water pressure are well-known causal or triggering factors for hillslope instability. Rainfall and snowmelt are generally assumed as the main sources of groundwater recharge. This assumption neglects the role of deep water inflow in highly tectonized areas, a factor that can influence long-term pore-pressure regimes and play a role on local slope instability. This paper aims to assess the origin of groundwater in the Ca' Lita landslide (northern Italian Apennines) and to qualify and quantify the aliquot attributable to deep water inflow. The research is essentially based on in situ monitoring and hydrochemical analyses. It involved 5 yr of continuous monitoring of groundwater levels, electrical conductivity and temperature and with groundwater sampling followed by determination of major ions (Na+, K+, Mg2+, Ca2+, Cl−, HCO3−, SO42−), tracers (such as Btot and Sr2+), and isotopes (δ18O, δ2H and 3H). Leaching experiments on soil samples, hydrochemical modelling and water recharge estimation were also carried out. Results show that the groundwater balance in the Ca' Lita landslide must take into account an inflow of deep and highly mineralised Na-SO4 water (more than 9500 μS cm−1) with non-negligible amounts of Cl− (up to 800 mg l−1). The chemical and isotopic fingerprint of this water points to oilfield water hosted at large depths in the Apennine chain and that uprises through a regional fault line crossing the landslide area. It recharges the aquifer hosted in the bedrock underlying the sliding surface (at a rate of about 49 000–85 700 m3 yr−1) and it also partly recharges the landslide body. In both the aquifers, the hydrochemical imprint of deep water mixed with rainfall and snowmelt water was observed. This indicates a probable influence of deep water inflow on the mobility of the Ca' Lita landslide, a finding that could be applicable to other large landslides occurring in highly tectonized areas in the northern Apennines or in other mountain chains. The paper demonstrates that hydrochemistry should, therefore, be considered as a valuable investigation method to define hydrogeological limits and the groundwater sources in hillslope and to assess groundwater flow patterns in deep-seated landslides.

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Deep-water clastic evaporites deposition in the Messinian Adriatic foredeep (northern Apennines, Italy): did the Mediterranean ever dry out?

Sedimentology ◽

10.1111/j.1365-3091.2005.00722.x ◽

2005 ◽

Vol 52 (4) ◽

pp. 875-902 ◽

Cited By ~ 94

Author(s):

VINICIO MANZI ◽

STEFANO LUGLI ◽

FRANCO RICCI LUCCHI ◽

MARCO ROVERI

Keyword(s):

Deep Water ◽

Northern Apennines ◽

The Mediterranean ◽

Dry Out

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Deep-water inflow event increases sedimentary phosphorus release on a multi-year scale

10.5194/bg-2021-5 ◽

2021 ◽

Author(s):

Astrid Hylén ◽

Sebastiaan J. van de Velde ◽

Mikhail Kononets ◽

Mingyue Luo ◽

Elin Almroth-Rosell ◽

...

Keyword(s):

Deep Water ◽

Oxygen Depletion ◽

Inorganic Phosphorus ◽

Phosphorus Release ◽

Water Inflow ◽

Low Oxygen ◽

In Situ Experiment ◽

Inflow Event ◽

Bottom Waters ◽

The Baltic

Abstract. Phosphorus fertilisation (eutrophication) is expanding oxygen depletion in coastal systems worldwide. Under low-oxygen bottom-water conditions, phosphorus release from the sediment is elevated which further stimulates primary production. It is commonly assumed that re-oxygenation could break this ‘vicious cycle’ by increasing sedimentary phosphorus retention. Recently, a deep-water inflow into the Baltic Sea created a natural in-situ experiment that allowed us to investigate if temporary re-oxygenation stimulates sedimentary retention of dissolved inorganic phosphorus (DIP). Surprisingly, during this three-year-long study, we observed a transient but considerable increase, rather than a decrease, in the sediment efflux of DIP and other dissolved biogenic compounds. This suggested that the oxygenated inflow elevated the organic matter degradation in the sediment. As a result, the net sedimentary DIP release per m2 was 35–70 % higher over the years following the re-oxygenation than before. In contrast to previous assumptions, our results show that inflows of oxygenated water to anoxic bottom waters can increase the sedimentary phosphorus release.

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A note on the deep-water inflow to the Bothnian Sea

Journal of Marine Systems ◽

10.1016/j.jmarsys.2006.12.004 ◽

2007 ◽

Vol 68 (1-2) ◽

pp. 255-264 ◽

Cited By ~ 8

Author(s):

Riikka Hietala ◽

Peter Lundberg ◽

Jenny A.U. Nilsson

Keyword(s):

Deep Water ◽

Water Inflow ◽

Bothnian Sea

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Progressive development of block-in-matrix fabric in a shale-dominated shear zone: Insights from the Bobbio Tectonic Window (Northern Apennines, Italy)

Tectonics ◽

10.1029/2011tc002924 ◽

2012 ◽

Vol 31 (1) ◽

pp. n/a-n/a ◽

Cited By ~ 9

Author(s):

Kei Ogata ◽

Gian Andrea Pini ◽

Davide Carè ◽

Mario Zélic ◽

Francesco Dellisanti

Keyword(s):

Shear Zone ◽

Northern Apennines ◽

Progressive Development ◽

Tectonic Window

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Temporal variability of the Circumpolar Deep Water inflow onto the Ross Sea continental shelf

Journal of Marine Systems ◽

10.1016/j.jmarsys.2016.05.006 ◽

2017 ◽

Vol 166 ◽

pp. 37-49 ◽

Cited By ~ 14

Author(s):

Pasquale Castagno ◽

Pierpaolo Falco ◽

Michael S. Dinniman ◽

Giancarlo Spezie ◽

Giorgio Budillon

Keyword(s):

Continental Shelf ◽

Deep Water ◽

Temporal Variability ◽

Ross Sea ◽

Water Inflow ◽

Circumpolar Deep Water

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The relationship between the open fractures and mineralized fractures in Oligocene sandstones of Leghorn coast (Tuscany, Italy) – the hydrogeological relapses

Hydrology and Earth System Sciences Discussions ◽

10.5194/hessd-7-2301-2010 ◽

2010 ◽

Vol 7 (2) ◽

pp. 2301-2316

Author(s):

A. Cerrina Feroni ◽

P. Martinelli

Keyword(s):

Conceptual Model ◽

Deep Water ◽

Northern Apennines ◽

Water Circulation ◽

Open Fractures ◽

Spatial Relationships ◽

Lower Zone ◽

Fractured Zone ◽

The Difference ◽

The Relationship

Abstract. The Oligocene-Miocene turbidite sandstones of fore-deep in the Northern Apennines form a very great aquifer that originally, before the reduction by Plio-Pleistocene erosion, is extended over an area of 60 000 sq/km (minimum) to 1.5 km–4.5 km tickness. The spatial relationships between the open fractures and mineralized fracture (veins) in the outcrops of foredeep's sandstones (Macigno) along the Tuscany coast, between Leghorn and Piombino (Northern Apennines), are analyzed and discussed. Also is discussed a conceptual model that allows a virtual surface of separation between an upper zone in open fractures and a fracture in the lower zone mineralization. The position of this surface than the topography surface, depends on the difference between the velocity of erosion and the velocity development of open fractures by reduction of the lithostatic load, during the exhumation of the system. The lack of the open fractured zone, below this surface suggests that the deep water circulation into the Macigno sandstones along the coast area, depends exclusively on the connection between the major faults and the primary discontinuity (stratification). Based on the results of fracturing analysis of the coastal Macigno the authors aim to extend the research to internal areas, and in particular to the ridge of the Northern Apennines, where the foredeep's sandstones are well developed and continued.

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Origin and assessment of deep groundwater inflow in the Ca' Lita landslide using hydrochemistry and in situ monitoring

Hydrology and Earth System Sciences Discussions ◽

10.5194/hessd-9-7699-2012 ◽

2012 ◽

Vol 9 (6) ◽

pp. 7699-7738

Author(s):

F. Cervi ◽

F. Ronchetti ◽

G. Martinelli ◽

T. A. Bogaard ◽

A. Corsini

Keyword(s):

Deep Water ◽

Major Ions ◽

Pore Water Pressure ◽

Water Pressure ◽

Slope Instability ◽

In Situ Monitoring ◽

Water Inflow ◽

Groundwater Levels ◽

Italian Apennines

Abstract. Changes in soil water content, groundwater flow and a rise in pore water pressure are well-known causal or triggering factors for hillslope instability. Rainfall and snowmelt are generally assumed as the only sources of groundwater recharge. This assumption neglects the role of deep water inflow in highly tectonized areas, a factor that can influence long-term pore-pressure regimes and play a role on local slope instability. This paper aims to assess the origin of groundwater in the Ca' Lita landslide (northern Italian Apennines) and to qualify and quantify the aliquot attributable to deep water inflow. The research is essentially based on in situ monitoring and hydrochemical analyses. It involved 5 yr of continuous monitoring of groundwater levels, electrical conductivity and temperature, and with groundwater sampling followed by determination of major ions, tracers (such as Boron and Strontium), and isotopes (Oxygen, Deuterium, Tritium). Leaching experiments on soil samples and water recharge estimation were also carried out. Results show that the groundwater balance in the Ca' Lita landslide must take into account an inflow of highly mineralized Na-SO4 water (more than 9500 μS cm−1) with non-negligible amounts of Chloride (up to 800 mg l−1). The deep water inflow recharges the aquifer hosted in the bedrock underlying the sliding surface (at a rate of about 7800–17 500 m3 yr−1). It also partly recharges the landslide body, where the hydrochemical imprint of deep water mixed with rainfall and snowmelt water was observed. This points to a probable influence of deep water inflow on the mobility of the Ca' Lita landslide, a finding that could be applicable to other large landslides occurring in highly tectonized areas in the northern Apennines or in other mountain chains.

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