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GeoBioScience: Red Wood Ants as Bioindicators for Active Tectonic Fault Systems in the West Eifel (Germany).

Berberich G, Schreiber U - Animals (Basel) (2013)

Bottom Line: The results showed linear alignments and clusters of approx. 3,000 RWA mounds.A possible cause can be found in occasionally occurring H₂S in the fault systems, which is toxic at miniscule concentrations to the ants.Viewed overall, there is a strong relationship between RWA mounds and active tectonics in the West Eifel.

View Article: PubMed Central - PubMed

Affiliation: Department of Geology, Faculty of Biology, University of Duisburg-Essen, Universitätsstr. 5, 45141 Essen, Germany. gabriele.berberich@uni-due.de.

ABSTRACT
In a 1.140 km² study area of the volcanic West Eifel, a comprehensive investigation established the correlation between red wood ant mound (RWA; Formica rufa-group) sites and active tectonic faults. The current stress field with a NW-SE-trending main stress direction opens pathways for geogenic gases and potential magmas following the same orientation. At the same time, Variscan and Mesozoic fault zones are reactivated. The results showed linear alignments and clusters of approx. 3,000 RWA mounds. While linear mound distribution correlate with strike-slip fault systems documented by quartz and ore veins and fault planes with slickensides, the clusters represent crosscut zones of dominant fault systems. Latter can be correlated with voids caused by crustal block rotation. Gas analyses from soil air, mineral springs and mofettes (CO₂, Helium, Radon and H₂S) reveal limiting concentrations for the spatial distribution of mounds and colonization. Striking is further the almost complete absence of RWA mounds in the core area of the Quaternary volcanic field. A possible cause can be found in occasionally occurring H₂S in the fault systems, which is toxic at miniscule concentrations to the ants. Viewed overall, there is a strong relationship between RWA mounds and active tectonics in the West Eifel.

No MeSH data available.


Related in: MedlinePlus

Relationship between soil gas anomalies and alignment of the RWA mounds for the Oberehe site (a) showing sampling points (black dots), (b) CO2 anomalies (>2 Vol%; blue dots and mineral springs (small blue dots)), (c) Radon anomalies (up to 74 Bq/L; green dots) and (d) Helium anomalies (He > 5,220 ppb; orange dots). In addition, the concentrations of the three gases in mineral springs are shown.
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animals-03-00475-f009: Relationship between soil gas anomalies and alignment of the RWA mounds for the Oberehe site (a) showing sampling points (black dots), (b) CO2 anomalies (>2 Vol%; blue dots and mineral springs (small blue dots)), (c) Radon anomalies (up to 74 Bq/L; green dots) and (d) Helium anomalies (He > 5,220 ppb; orange dots). In addition, the concentrations of the three gases in mineral springs are shown.

Mentions: In 2009 and 2012, 128 soil gas analyses (cf.Figure 9(a)) were carried out at the reference location Oberehe (Klerf schists of the Middle Devonian) in order to evaluate the relationship between active tectonics, geogenic degassing structures and spatial RWA distribution pattern. Therefore, it was the objective to measure the geogenic gas concentrations in close proximity to the mounds to get as much information on the degassing structures as possible. In areas without RWA mounds control samplings were performed (in 1 km distance). Compared to their atmospheric concentrations (0.0370 Vol% CO2, 5,220 ppb He, 0.01 kBq/m3 Rn, 1.5 ppm CH4 and 0.002 ppm H2S) and the regional average background values for Helium (5,202 ppb [28]) and Rn (46 Bq/L [56]), the soil gases showed different concentrations (cf.Table 2). Neither CH4 nor H2S were present.


GeoBioScience: Red Wood Ants as Bioindicators for Active Tectonic Fault Systems in the West Eifel (Germany).

Berberich G, Schreiber U - Animals (Basel) (2013)

Relationship between soil gas anomalies and alignment of the RWA mounds for the Oberehe site (a) showing sampling points (black dots), (b) CO2 anomalies (>2 Vol%; blue dots and mineral springs (small blue dots)), (c) Radon anomalies (up to 74 Bq/L; green dots) and (d) Helium anomalies (He > 5,220 ppb; orange dots). In addition, the concentrations of the three gases in mineral springs are shown.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4494391&req=5

animals-03-00475-f009: Relationship between soil gas anomalies and alignment of the RWA mounds for the Oberehe site (a) showing sampling points (black dots), (b) CO2 anomalies (>2 Vol%; blue dots and mineral springs (small blue dots)), (c) Radon anomalies (up to 74 Bq/L; green dots) and (d) Helium anomalies (He > 5,220 ppb; orange dots). In addition, the concentrations of the three gases in mineral springs are shown.
Mentions: In 2009 and 2012, 128 soil gas analyses (cf.Figure 9(a)) were carried out at the reference location Oberehe (Klerf schists of the Middle Devonian) in order to evaluate the relationship between active tectonics, geogenic degassing structures and spatial RWA distribution pattern. Therefore, it was the objective to measure the geogenic gas concentrations in close proximity to the mounds to get as much information on the degassing structures as possible. In areas without RWA mounds control samplings were performed (in 1 km distance). Compared to their atmospheric concentrations (0.0370 Vol% CO2, 5,220 ppb He, 0.01 kBq/m3 Rn, 1.5 ppm CH4 and 0.002 ppm H2S) and the regional average background values for Helium (5,202 ppb [28]) and Rn (46 Bq/L [56]), the soil gases showed different concentrations (cf.Table 2). Neither CH4 nor H2S were present.

Bottom Line: The results showed linear alignments and clusters of approx. 3,000 RWA mounds.A possible cause can be found in occasionally occurring H₂S in the fault systems, which is toxic at miniscule concentrations to the ants.Viewed overall, there is a strong relationship between RWA mounds and active tectonics in the West Eifel.

View Article: PubMed Central - PubMed

Affiliation: Department of Geology, Faculty of Biology, University of Duisburg-Essen, Universitätsstr. 5, 45141 Essen, Germany. gabriele.berberich@uni-due.de.

ABSTRACT
In a 1.140 km² study area of the volcanic West Eifel, a comprehensive investigation established the correlation between red wood ant mound (RWA; Formica rufa-group) sites and active tectonic faults. The current stress field with a NW-SE-trending main stress direction opens pathways for geogenic gases and potential magmas following the same orientation. At the same time, Variscan and Mesozoic fault zones are reactivated. The results showed linear alignments and clusters of approx. 3,000 RWA mounds. While linear mound distribution correlate with strike-slip fault systems documented by quartz and ore veins and fault planes with slickensides, the clusters represent crosscut zones of dominant fault systems. Latter can be correlated with voids caused by crustal block rotation. Gas analyses from soil air, mineral springs and mofettes (CO₂, Helium, Radon and H₂S) reveal limiting concentrations for the spatial distribution of mounds and colonization. Striking is further the almost complete absence of RWA mounds in the core area of the Quaternary volcanic field. A possible cause can be found in occasionally occurring H₂S in the fault systems, which is toxic at miniscule concentrations to the ants. Viewed overall, there is a strong relationship between RWA mounds and active tectonics in the West Eifel.

No MeSH data available.


Related in: MedlinePlus