Evaporite sedimentation in a tectonically active basin: The lacustrine Las Minas Gypsum unit (Late Tortonian, SE Spain)

Ortı́, Federico; Rosell, Laura; Gibert, Luís; Moragas, Mar; Playà, Elisabet; Inglés, M.; Rouchy, J. M.; Calvo, J.P.; Gimeno, D.

doi:10.1016/j.sedgeo.2014.06.004

Cited by 23 publications

(36 citation statements)

References 29 publications

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“…These values might have been originally higher (at least 5-16 wt. %) in accordance with TOC contents found in drilling samples from sulfur mining in analogous nearby basins of the same age [38,45]. The syntectonic minor faults and joints related to the Socovos Fault (Figure 14b,c) might have acted as preferential air flow paths that favoured the penetration of oxygen some metres below the topographic surface, within reach of the burn zone (the organic-rich clay layers), thus supporting the maintenance and propagation of the fire and facilitating the evacuation of the combustion products and smoke.…”

Section: Origin Of Pyrometamorphismsupporting

confidence: 87%

“…Dark brown to black pelitic layers are found near the pyrometamorphic outcrop separated by a local discordance from the more calcareous sequence on top of them. Organic-rich levels similar to these are described in most of the neighbouring basins [38,45]. Actually, some of these basins have well-known sulphur deposits formed after reduction of sulphates in contact with bituminous lutites or shales [46,47].…”

Section: Geological Settingmentioning

confidence: 77%

“…In addition, P-T pseudosection calculations from the plausible protolith are compared with the observations in order to understand and explain the origin and the temperature evolution of the observed variety of lithologies and its relationships. Names of the basins from previous studies e.g., [36][37][38] and this study: 1, Híjar; 2, Isso; 3, Molinicos; 4, Elche de la Sierra; 5, Cobatillas; 6, Gallego; 7, Cenajo; 8 Las Minas-Camarillas; 9, El Cañar; 10, Férez; 11, Letur. Inset: Location map of the studied area in the SE of the Iberian Peninsula.…”

Section: Introductionmentioning

confidence: 86%

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Pyrometamorphic Rocks in the Molinicos Basin (Betic Cordillera, SE Spain): Insights into the Generation of Cordierite Paralavas

et al. 2019

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A singular thermal anomaly occurred in the Molinicos Miocene, lacustrine, intramontane basin (Betic Cordillera). This gave place to vitreous vesicular materials (paralavas) and baked rocks (clinker) inside of a sequence of marly diatomites and limestones. The chemical composition of the paralavas (SiO 2 = 52-57, Al 2 O 3 ≈ 20, Fe 2 O 3 = 10-20, K 2 O + Na 2 O < 2.5, CaO < 4.5, and MgO < 1.5, % in weight), which is very different from typical igneous rocks, and their high-T mineralogy (cordierite, sillimanite, anorthite, mullite, and high-T silica polymorphs) suggest that they formed during a pyrometamorphic event. The occurrence of dry intervals in the lacustrine depositional system, the high Total Organic Carbon contents (>4% in weight) of dark clay layers and the existence of tectonic fractures give the right context for a combustion process. Short-term heating favoured the generation of paralavas, clinker and marbles. Thermodynamic modelling constrains the onset of melting at 870-920 • C for <10 MPa at equilibrium conditions. However, the presence of tridymite and/or cristobalite in clinker and paralavas and the compositional variation in both rock types suggests that the temperature at which first melting occurred ranged between 870 • C and 1260 • C due to melt fractionation processes.Minerals 2019, 9, 748 2 of 24 evacuation of combustion products [22]. At the same time, thermal isolation is necessary to accumulate locally enough heat until an activation threshold is reached [29]. Thus, depth and extension of the fires are commonly restricted to some tens of square metres, limited in addition by the position of the water table. However, much larger areas have been described reaching hundreds of square kilometres [22].During combustion metamorphism, the sedimentary rocks around the ignition foci are subjected to certain changes in addition to common dehydration, and decarbonation in case CaCO 3 is present. Firstly, the rocks are hardened and, later, they become sintered and recrystallised producing a ceramic texture. The colour of the rocks is also progressively changed from yellow to more intense orange and red, due to iron oxidation, and finally even grey and black when reducing conditions are reached. In any case, this intense thermal metamorphism triggers only limited fusion of the sediments. The released melts may flow along fractures but usually undergo fast cooling producing small amounts of glass with particular mineral assemblages and textures similar to those of fine-grained volcanic rocks. These rocks, which show features and parageneses merging with those of igneous rocks, are called paralavas and the associated baked or partially melted sedimentary rocks are denominated clinker e.g., [24,[31][32][33][34]. According to Cosca and Essene [35] the mineral assemblages produced in paralavas are partly a function of the temperature, degree of partial melting, and oxidation state related to local gas buffers, in addition to the original bulk composition of the sedimentary protolith. Fast heating and subs...

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Section: Origin Of Pyrometamorphismsupporting

confidence: 87%

Section: Geological Settingmentioning

confidence: 77%

Section: Introductionmentioning

confidence: 86%

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Pyrometamorphic Rocks in the Molinicos Basin (Betic Cordillera, SE Spain): Insights into the Generation of Cordierite Paralavas

et al. 2019

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“…It can be assigned to calcite, aragonite or vaterite, which are calcium carbonate polymorphs. The remaining 2% consist of Al 2 O 3 , Cl, Na 2 O, SrO and SO 3 , indicating that the other mineral impurities correspond to clay minerals and evaporites, such as halite, celestine and gypsum, expected from evaporitic shallow lacustrine environments, as is the case of the Elche de la Sierra basin [21]. The Mg content in the samples could be either associated with clay minerals, such as montmorillonite, or with carbonates, in the form of dolomite.…”

Section: Xrf Characterisationmentioning

confidence: 99%

“…Neogene basins on the external side of the Betic Ranges, and location of the Elche de la Sierra basin (black rectangle in the upper-left corner) (modified from[21]). …”

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confidence: 99%

The Use of Infrared Spectroscopy to Determine the Quality of Carbonate-Rich Diatomite Ores

Guatame-Garcia¹,

Buxton²

2018

Minerals

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Diatomite, a rock formed by the accumulation of opaline diatom frustules, is a preferred raw material for the manufacturing of filters. Its uniqueness relies on the high porosity and inertness of the frustules. The presence of carbonates in some diatomite ores hinders these properties. The purpose of this study was to identify the type of carbonates and their association with the ore in a diatomite deposit, and to assess the suitability of determining the quality of the ore using techniques with potential for in-pit implementation. For this, run-of-mine samples were analysed using environmental scanning electron microscopy (ESEM) and infrared spectroscopy. The ESEM images showed that carbonate is present as cement and laminae. The infrared data revealed that the carbonate minerals correspond to aragonite and calcite, and that their occurrence is linked to the total amount of carbonate in the sample. By using a portable spectral instrument that uses diffuse reflectance, it was possible to classify the spectra of the ore samples based on the carbonate content. These results indicate that infrared technology could be used on-site for determining the quality of the ore, thus providing relevant information to assist the optimisation of mining and beneficiation activities.

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Large-Scale Slumps and Associated Resedimented Deposits in Miocene Lake Basins from SE Spain

Calvo

Gómez‐Gras

Rodríguez-Pascua

2021

Limnogeology: Progress, Challenges and Opportunities

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Evaporite sedimentation in a tectonically active basin: The lacustrine Las Minas Gypsum unit (Late Tortonian, SE Spain)

Cited by 23 publications

References 29 publications

Pyrometamorphic Rocks in the Molinicos Basin (Betic Cordillera, SE Spain): Insights into the Generation of Cordierite Paralavas

Pyrometamorphic Rocks in the Molinicos Basin (Betic Cordillera, SE Spain): Insights into the Generation of Cordierite Paralavas

The Use of Infrared Spectroscopy to Determine the Quality of Carbonate-Rich Diatomite Ores

Large-Scale Slumps and Associated Resedimented Deposits in Miocene Lake Basins from SE Spain

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