A Field Guide to the Spectacular Salt Mines of the Transylvanian Basin and Romanian Carpathians

Tămaș, Dan Mircea; Tămaș, Alexandra; Jüstel, Alexander; Passchier, Martijn; Chudalla, Nils; Gotzen, Lina; Wagner, Luis Alberto Pizano; Tașcu-Stavre, Teodora; Schléder, Zsolt; Krézsek, Csaba; Filipescu, Sorin; Urai, János

doi:10.1007/978-3-030-60143-0_6

Cited by 2 publications

(1 citation statement)

References 30 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Salt mines from Romania (Figures 1, 2) are distributed in different seismogenic zones, geographically located in the Romanian Carpathians and Transylvanian Basin (Tămaș et al 2021). Târgu Ocna and Slănic Prahova are the most vulnerable ones.…”

Section: Resultsmentioning

confidence: 99%

Mines (Salt and Gold) and Infrastructure Underground Built Heritage Survey: Romania, Contribution to the COST Action

Dan¹,

Anghelache²,

Petrişor³

et al. 2021

11th Congress of the Balkan Geophysical Society

View full text Add to dashboard Cite

This paper approaches the particularities of Romanian heritage, from the view point of endangered mining sites and infrastructure. Several examples are addressed, including: i) salt mines, particular example of successful conversion of Turda salt mine in an underground leisure center; ii) mining heritage, the saving of Roman galleries from the Rosia Montana region, which are the living evidence of 2000 years of gold mining on Romanian territory; iii) the infrastructure heritage, with the example of Suceava water plant, where a concrete half tube with no windows was buried by a slope greened with geotextile reinforced earth, reconstructing the landscape.

show abstract

Section: Resultsmentioning

confidence: 99%

Mines (Salt and Gold) and Infrastructure Underground Built Heritage Survey: Romania, Contribution to the COST Action

Dan¹,

Anghelache²,

Petrişor³

et al. 2021

11th Congress of the Balkan Geophysical Society

View full text Add to dashboard Cite

show abstract

Rheological stratification in impure rock salt during long-term creep: morphology, microstructure, and numerical models of multilayer folds in the Ocnele Mari salt mine, Romania

et al. 2021

Self Cite

View full text Add to dashboard Cite

Abstract. At laboratory timescales, rock salt samples with different composition and microstructure show variance in steady-state creep rates, but it is not known if and how this variance is manifested at low strain rates and corresponding deviatoric stresses. Here, we aim to quantify this from the analysis of multilayer folds that developed in rock salt over geological timescale in the Ocnele Mari salt mine in Romania. The formation is composed of over 90 % of halite, while distinct multiscale layering is caused by variation in the fraction of impurities. Regional tectonics and mine-scale fold structure are consistent with deformation in a shear zone after strong shearing in a regional detachment, forming over 10 m scale chevron folds of a tectonically sheared sedimentary layering, with smaller folds developing on different scales in the hinges. Fold patterns at various scales clearly indicate that during folding, the sequence was mechanically stratified. The dark layers contain more impurities and are characterised by a more regular layer thickness compared to the bright layers and are thus inferred to have higher viscosities. Optical microscopy of gamma-decorated samples shows a strong shape-preferred orientation of halite grains parallel to the foliation, which is reoriented parallel to the axial plane of the folds studied. Microstructures indicate dislocation creep, together with extensive fluid-assisted recrystallisation and strong evidence for solution–precipitation creep. This provides support for linear (Newtonian) viscous rheology as a dominating deformation mechanism during the folding. Deviatoric stress during folding was lower than during shearing in the detachment at around 1 MPa. We investigate fold development on various scales in a representative multilayer package using finite-element numerical models, constrain the relative layer thicknesses in a selected outcrop, and design a numerical model. We explore the effect of different Newtonian viscosity ratios between the layers on the evolving folds on different scales. By comparing the field data and numerical results, we estimate that the effective viscosity ratio between the layers was larger than 10 and up to 20. Additionally, we demonstrate that the considerable variation of the layer thicknesses is not a crucial factor to develop folds on different scales. Instead, unequal distribution of the thin layers, which organise themselves into effectively single layers with variable thickness, can control deformation on various scales. Our results show that impurities can significantly change the viscosity of rock salt deforming at low deviatoric stress and introduce anisotropic viscosity, even in relatively pure layered rock.

show abstract

A Field Guide to the Spectacular Salt Mines of the Transylvanian Basin and Romanian Carpathians

Cited by 2 publications

References 30 publications

Mines (Salt and Gold) and Infrastructure Underground Built Heritage Survey: Romania, Contribution to the COST Action

Mines (Salt and Gold) and Infrastructure Underground Built Heritage Survey: Romania, Contribution to the COST Action

Rheological stratification in impure rock salt during long-term creep: morphology, microstructure, and numerical models of multilayer folds in the Ocnele Mari salt mine, Romania

Contact Info

Product

Resources

About