Tectonic and Metallogenic Significance of Sedimentary Manganese Deposits in the Eastern Cantabrian Domain, Asturias, Northwestern Spain

Martínez‐García, Enrique; Antona, J. F.; Sánchez, A. García; Vega, J. L. Quiroga de la

doi:10.2747/0020-6814.46.3.273

Cited by 8 publications

(7 citation statements)

References 17 publications

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“…There are two separate sets of intrusions reported in the W of the Asturian segment: at 285 Ma porphyritic subvolcanic intrusives, with an associated hydrothermal system, and at 255 Ma a generation of diabasic dykes that also have an associated hydrothermal system (Martín-Iz-ard et al 2000). Structures with NW orientation have significant ore deposits associated with hydrothermal fluids, the ages of the majority of the intrusions and associated ore bodies yield Permian ages (Martín-Izard et al 2000;Martínez-García et al 2004).…”

Section: Discussion Geological Interpretation Of the Rnmentioning

confidence: 99%

Radon concentration in caves as a proxy for tectonic activity in The Cantabrian Mountains (Spain)

Ballesteros

Llana‐Fúnez

Meléndez-Asensio

et al. 2021

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Radon (Rn) constitutes a good geochemical tracer for neotectonic activity in faults since associated fracturing near the surface favours fluid escape to the atmosphere. In this contribution, we measured the Rn concentration in the air inside karst caves to constraints the recent fault activity in the Cantabrian Mountains (N Spain). Rock formations exhumed during the uplifting of the Cantabrian Mountains record a long history of fracturing, which has the potential to connect deeper sources of Rn with the surface. In this regional study, we correlate Rn measurements with cave survey data and geological structures using a Geographic Information Systems. Thirty-four Rn average concentration was recorded by CR-39 detectors during 8 integrated months. The method is applied to the central part of the Cantabrian Mountains that is built on sedimentary and low-grade metamorphic rocks relatively poor in U. Dominant tectonic structures and Rn concentration are examined in 28 cavities. The concentration of Rn values is higher than 0.5 kBq·m-3 in caves developed preferably following fractures with the direction N30oW, being the concentration greater than 0.8 kBq·m-3 in cavities located less than 200±50 m from subvertical faults with such orientation. Rn anomalies point to relative high connectivity along subvertical fault zones NW-trending, preserving fracture connectivity in the most recent structures in the Cantabrian Mountains. Finally, in the study area there is a low but significant radioactive hazard which is associated to fault zones in a fractured rock massif. It contrasts with other active tectonic settings where the radioactive hazard may come from fault movements.

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Section: Discussion Geological Interpretation Of the Rnmentioning

confidence: 99%

Radon concentration in caves as a proxy for tectonic activity in The Cantabrian Mountains (Spain)

Ballesteros

Llana‐Fúnez

Meléndez-Asensio

et al. 2021

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“…Although the cartographic pattern is straightforward through the Paleozoic formations onshore, which are steeply dipping, its recognition becomes more challenging through the Mesozoic units, which are flat lying and not so well exposed. There are parts of the fault onshore that reactivate Permian extensional structures, as the main fault bounds some of the small Permian basins (Martínez-García et al, 2004), and others that reactivate earlier Variscan structures (Alonso et al, 2009). The movements and evolution along the long-stretched history are not fully understood.…”

Section: The Ventaniella-cantabrian Fault Systemmentioning

confidence: 99%

“…The latest major tectonic Variscan structure in northwestern Iberia dates from the early Permian (e.g., López-Sánchez and Llana-Fúnez, 2018). More than 50 ma later, in the Late Permian, the nascent rift cut obliquely across major variscan structures (Arche and López-Gómez, 1996) producing several northwesterly trending faults with minor basins and associated local volcanism (Martínez-García et al, 2004).…”

mentioning

confidence: 99%

The Cantabrian Fault at Sea. Low Magnitude Seismicity and Its Significance Within a Stable Setting

et al. 2021

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The Cantabrian fault (CF) is a crustal-scale structure that cuts obliquely the western North Iberian Margin (NIM) for 160 km and continues onshore transecting the Cantabrian Mountains (CM) for another 150 km as the Ventaniella fault (VF). For most of its length inland, the fault system is aseismic, except for a 70 km long segment at its southern end. Within this segment, a gently north-dipping linear arrangement of earthquakes was interpreted as related to the intersection of a slightly oblique fault to VF with the basal thrust of the CM. In addition to earthquake nucleation along parts of its length, the CF–VF also stands out regionally as a major seismotectonic boundary, separating a seismically active area to the West from an essentially aseismic region to the East. Contrasting tectonothermal evolution in the crust on either side during the Mesozoic rifting may underlie the observed differences. On the other hand, the seismicity within the subsea segment is low magnitude, persistent, and understudied. The scarcity of the permanent seismic stations distribution in the area did not allow to establish more than a generalized consensus relating the offshore events to the submarine structure. A recent local seismic network monitored the area providing the highest accuracy information on the offshore events to date. Although the location of foci is partially challenged by the lack of recording stations from northern azimuths at sea, the observed pattern shows indeed a broad linear trend in the submarine domain in relation to the crustal-scale structure. Specifically, this study shows that the distribution of foci offshore display two preferential areas along the CF–VF within its southern crustal block. Considering the basement rock types and the deep architectural disposition of the margin crust, two possible explanations for the origin of the clusters are put forward in this contribution.

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“…3). They are mainly Cu, Co-Ni, Pb-Zn, Hg-As, Fe-Mn, barite and fluorite mineralizations (Martínez-García, 1981, 1983Luque & Martínez-García, 1985;Martínez-García & Tejerina, 1985;Martín-Izard, Paniagua & Arias, 1995;Gutiérrez-Claverol & Luque, 2000;Martínez-García et al 2004;Luque & Gutiérrez-Claverol, 2006). With the exception of some Mn deposits, which have been interpreted as syngenetic (Martínez-García et al 2004), the rest of the deposits have been considered epigenetic and epithermal in origin, with formation temperatures between 100 and 150…”

Section: S B L a N C O -F E R R E R A A N D Ot H E R Smentioning

confidence: 99%

“…With the exception of some Mn deposits, which have been interpreted as syngenetic (Martínez-García et al . 2004), the rest of the deposits have been considered epigenetic and epithermal in origin, with formation temperatures between 100 and 150°C (Martín-Izard, Paniagua & Arias, 1995), or <200°C (Loredo & García Iglesias, 1981; Luque & Martínez-García, 1985; Luque, Martínez-García & Ruiz, 1990), and low pressure (20–60 MPa; Luque & Martínez García, 1985; Luque, Martínez-García & Ruiz, 1990). Most of them are hosted by Carboniferous limestones and have a strongly associated dolomitization and silicification.…”

Section: Geological Settingmentioning

confidence: 99%

Conodont alteration and tectonothermal evolution of a diagenetic unit in the Iberian Variscan belt (Ponga-Cuera unit, NW Spain)

et al. 2010

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-Tectonothermal analysis of a mainly carbonate unit located in the external part of the Variscan orogen in NW Spain is dealt with using the conodont colour alteration index (CAI) and the study of textures of these microfossils. The Kübler index of the illite (KI) is used as a complementary method. The area is characterized by a great uniformity in the CAI values, which in most cases are < 2, indicating diagenetic conditions. In spite of the low CAI values, textures show great variety and were mainly originated by diagenetic processes of apatite dissolution and precipitation. The conodonts underwent a long period of heating (probably from the Pennsylvanian to the Cenozoic) to low temperatures (< 100• C) to reach the low CAI values measured. Assuming a normal geothermal gradient, these temperatures required an overburden < 3 km that in part was due to burial and in part to tectonic superimposition. Minor local anomalies in the CAI values and some textural alterations, related to dissolution and precipitation of authigenic minerals, could be due to epithermal activity that gave rise to various ore deposits in the studied area mainly during Permian times.

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Tectonic and Metallogenic Significance of Sedimentary Manganese Deposits in the Eastern Cantabrian Domain, Asturias, Northwestern Spain

Cited by 8 publications

References 17 publications

Radon concentration in caves as a proxy for tectonic activity in The Cantabrian Mountains (Spain)

Radon concentration in caves as a proxy for tectonic activity in The Cantabrian Mountains (Spain)

The Cantabrian Fault at Sea. Low Magnitude Seismicity and Its Significance Within a Stable Setting

Conodont alteration and tectonothermal evolution of a diagenetic unit in the Iberian Variscan belt (Ponga-Cuera unit, NW Spain)

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