Salt Glaciers Research Articles

Rapid evolution of salt glacier caves on a mountain diapir in a semiarid climate

Salt caves occur mostly in hyperarid and arid climates and are typically a few thousand years old. There is little data on the evolution of salt caves in semiarid climates, and no data on caves developed in salt glaciers, i.e., salt masses spreading under their own weight, similar to ice glaciers. The age of salt caves and the incision rates of cave streams were studied on a salt glacier of the Jahani diapir in a semiarid climate, Zagros Mts., Iran. Wood fragments from 3 caves sampled 0–11.3 m above the present streambed were dated by AMS 14C. The cave passages accessible today were developed during the last ~600 years at the Jahani. The cave level 5–6 m above the present streambed was formed 1520–1660 CE or slightly earlier, then the stream incised upward and reached its highest level between 1690 and 1920 CE or slightly earlier. Then, the downward incision started. This indicates that caves in semiarid climates evolve extremely rapidly. The maximum vertical incision rate of the cave stream on the semiarid Jahani diapir is 20–110 mm/yr, which is faster than 0.4–25 mm/yr in caves in hyperarid climates. The incision rate of the cave stream at the Jahani exceeds the denudation rate of the thick cap soil surface, being comparable to the denudation rate of salt exposures. The persistence of the steep longitudinal profiles of the integrated salt caves at the Jahani is probably caused by the transport of very coarse sediment. Aggradation was probably caused either by blocking of cave passages by earthquakes or by more intense erosion of the cap soil. The salt glacier at the Jahani is moving slowly (<10 mm/yr); claims that this glacier is the fastest on Earth (velocity in the range of m/yr) are based on a study that did not follow geodetic standards and are in strong disagreement with the age of the caves and other lines of evidence.

Secondary minibasins in orogens: Examples from the Sivas Basin (Turkey) and the sub-Alpine fold-and-thrust belt (France)

Inherited and syn-compressional salt-controlled structures in orogens are difficult to distinguish from compressional features because classical salt features (halokinetic growth strata, salt welds) can be misinterpreted as shortening-related structures (syn-kinematic growth strata, tectonic unconformities). In the Sivas basin in Turkey, syn-kinematic salt diapirism entirely shaped the architecture of the foreland and allowed the development of primary and secondary minibasins. One of the most impressive, the Tuzlagözü minibasin, formed by sinking into a salt feeder while being upturned due to compression. This minibasin has been nicknamed the “Turkish Vélodrome” because of its similarity with the well-known Vélodrome structure in the French Alps which shows growth strata and successive unconformities, commonly interpreted as foreland growth syncline features. Based on structural field descriptions and geometric analogies with the Tuzlagözü minibasin, we revisit the Vélodrome as a salt-related minibasin. We argue that the Vélodrome developed as a secondary minibasin above an Oligocene aerial salt glacier: sheet of Upper Triassic evaporites extruded during Alpine orogeny. This new interpretation enables to propose a revised evolution of the sub-Alpine fold-and-thrust belt. In line with other recent works, this study emphasises once again the important role of salt tectonics in the evolution of the sub-Alpine fold-and-thrust belt.

Composition and deformation patterns of the caprock on salt extrusions in southern Iran – Field study on the Karmostaj and Siah Taq diapirs

Two iconic salt diapirs in the Zagros Mountains in Iran – Karmostaj (Gach) and Siah Taq – are regarded as world-class examples of salt extrusions and are frequently called "salt glaciers". However, our field survey revealed that their glacier-like parts are formed by thick, variegated and deformed caprock, only locally mixed with salt. Caprock is a layer of insoluble residuum that consists primarily of dissolution breccia and gypsum surrounding blocks of non-halite lithologies of the original evaporite sequence. Deformation within the caprock was accommodated primarily by shearing along gypsum-rich zones (gypsum mylonites) that surround subdomains of dissolution breccia and folded and fragmented blocks of carbonates and siliciclastics. Ductile flow in these mylonite shear zones was accommodated by pressure solution-precipitation creep of the lath-shaped gypsum grains. The ductile shearing of gypsum was locally accompanied by increased fluid-pore pressure driven fracturing of the surrounding lithologies. Since the subsurface shape of the salt diapirs is unknown, we present three hypothetical scenarios trying to explain the extrusion process of the studied diapirs and the associated deformation history of their caprocks. The diapiric structures represent either, 1) the remnants of degraded paleoglaciers, 2) advancing salt extrusions, or 3) only slightly reactivated, wide diapirs. To test these hypothetical scenarios, a geophysical survey is required to gain insights into the subsurface structures of the exposed diapirs and salt sheets.

The banded terrain on northwestern Hellas Planitia: New observations and insights into its possible formation

Northwestern Hellas Planitia hosts landforms that are unique on Mars, e.g., the so called honeycomb and banded (aka “taffy pull”) terrains. Recently, robust formation models for the ∼6 km large honeycomb depressions involving salt or ice diapirism have been formulated. However, the nature of the banded terrain, a ∼30,000 km² area characterized by a decameter- to kilometer-scale pattern of curvilinear troughs, has remained elusive. While previous interpretations range from deep-seated, honeycomb-related outcrops to a younger veneer, recent reports of putative periglacial features (e.g., potential thermokarst) strongly indicate it to be a relatively thin, volatile-related surface unit. In order to further constrain the origin and nature of the banded terrain, we investigated the northwestern Hellas basin floor employing various datasets. We mapped the banded terrain's extent at high precision, showing that it partially superposes the honeycomb terrain, but also occurs up to ∼240 km away from it. Via stratigraphic analyses and crater size-frequency measurements, we bracketed the age of the banded terrain between ∼1.9 and ∼3.7 Ga. Furthermore, the banded terrain can be differentiated into two types, ridged and creviced, with the former predominantly occurring among the lowest reaches of the terrain's ∼2 km topographic extent. We also produced a grid map (2 × 2 km box size) of the entire banded terrain and identified no large-scale (> 25 km) band pattern and no correlation between local slope and band orientation. Because of this, we submit that regional tectonics or gravity-driven flow down modern topography are unlikely to have played decisive roles for banded terrain formation. Instead, we observed numerous locations, where band slabs appear to have broken off and subsequently rotated, as well as “cusps” that seem to have resulted from buckling. Based on this, we suggest that the banded terrain experienced both, ductile deformation as well as brittle failure on or near the surface. Despite certain similarities, neither salt (as salt glaciers), lava sheets, or land-based glaciers are in agreement with the extensive curvilinear texture and topographic/geologic setting of the banded terrain. Ice shelf margins, on the other hand, can produce surface textures akin to the banded terrain in both form and scale, even including cusps and broken off, rotated blocks. However, an ice-covered sea between 1.9 and 3.7 Ga ago is not indicated by the geologic inventory of the Hellas basin, which previous investigations found to lack any landforms indicative of a standing body of water. Instead, we identified several sinuous ridges terminating at plains covered by smaller, braiding ridges, which we interpret as eskers and glacial sandurs, respectively. As both are embayed and partially covered by the banded terrain, we tentatively propose an alternative, subglacial model of the banded terrain having formed as wet till that was viscously deformed according to the stress fields created by the ice overburden pressure in conjunction with bed topography. Although this formation model remains inconclusive, it is in agreement with climate models suggesting obliquity excursions and a denser, early Amazonian atmosphere to have caused ice accumulation in the adjacent northwestern Hellas basin rim, thus potentially enabling flow onto the floor entailing subglacial banded terrain formation.

Triassic salt sheets of Mezzouna, Central Tunisia: New comments on Late Cretaceous halokinesis and geodynamic evolution of the northern African margin

Two discrete Triassic salt sheets have been discovered within the Coniacian–Santonian series near the salt wall of Mezzouna, central Tunisia. The structure and the lithology of these sheets suggest two halokinetic episodes giving respectively 1) Triassic evaporitic rocks flows over a sloped basin floor resulting in probable salt glacier, and 2) redeposition of erosional debris from the nearby salt wall of Mezzouna, transported and then deposited next to the wall. This finding is used to precise the halokinetic events and the geodynamic evolution of the northern African margin near the Pelagian block between southeastern Tunisia and Tripolitania during Late Cretaceous. A discussion of the halokinesis-related structures is also attempted with emphasize of their genetic mechanisms and temporal development as inferred from geological mapping and new field data.

Halocinese and Halotectonics in the Northern Atlas: Case Study of the Triassic Outcrop of J. El Matria (Oued Zarga Area)

Apart from the Triassic bodies, there are several structural elements that characterize the Oued Zarga area. The new field data allowed us to deduce that the structural evolution of this region is essentially based on two generations of dextral strike-slip faults: an E-W direction to WNW-ESE and a later NW-SE second trend. In the study area, the Triassic material of J. El Matria is framed by two sedimentary contacts. Lower contact in clansayesian clays characterized by a glauconic to Triassic insoluble conglomerates and an upper contact where the Triassic material is covered by a thick pelagic series attributed to the lower Albian. This configuration results from a rapid lateral outpouring during the Lower Cretaceous in an extensive tectonic context and re-folded during the tertiary compressive phases, interpreted like most Triassic structures in northern Tunisia, in terms of the salt glacier with Lower Cretaceous age.

Hydrothermal Systems in the Salt Domes of South Iran

The intrusion of less dense rock salt into denser overburden sediments can create salt diapirs. In the north of the Persian Gulf about 200 salt-gypsum domes are exposed, partially forming impressive salt glaciers. With the emergence of the salt domes exotic blocks of igneous and metamorphic rocks are also brought out to the surface. They are often intensively altered. Minerals, such as albite, quartz, hematite, coarse grained dolomite and apatite are widespread. The growth of blue amphiboles (magnesio-riebeckite) in veins of altered rocks indicate an intensive interaction of hydrothermal fluids with the host rocks in the salt diapirs.

Three-dimensional evolution of salt-controlled minibasins: Interactions, folding and megaflap development

A megaflap, or an overturned, folded, sedimentary-basin edge, is a classic feature of salt-controlled basins, formed during the inception of salt allochthony. To illustrate the relative importance of the balance between salt and sediment inputs, basin rheology, and tectonism resulting from basin interactions in the development of megaflaps, a set of analog experiments were performed in a computed tomography scanner. Sediments are modeled using both granular material and a mix of granular and viscous material and salt as purely viscous material. Uneven sedimentary loading and associated salt flow localize primary minibasins, which then migrate and expand laterally until sufficient thickness is reached to pin the downbuilding phase. The encasement of minibasins into the mother-salt layer is followed by secondary minibasin development above the canopy, the inception and localization of which appear to be more locally controlled by the primary salt feeders, salt glaciers, and canopies. Enhanced salt extrusion along basin edges is responsible for (1) classic halokinetic sequences, (2) major wedging and basin-edge erosion, and (3) basin-edge backfolding onto the basin centers, forming megaflaps. Basin interactions during differential subsidence and secondary minibasin development above the allochthonous salt canopy result in the formation of salt welds and tectonic deformation at basin boundaries, including broken and transported basin edges. The major controlling factor in megaflap development is salt allochthony, which allows the local salt extrusion rate to be higher than the sedimentation rate. Enhanced allochthony is the result of enhanced pressure related to local salt stock squeezing, regional shortening, or basin tilting.

Geomorphology of the central Red Sea Rift: Determining spreading processes

Continental rifting and ocean basin formation is occurring today in the Red Sea, providing a possible modern analogue for the creation of mid-ocean ridges. Yet many of the seafloor features observed along the axis of the Red Sea appear anomalous compared to ancient and modern examples of mid-ocean ridges in other parts of the world, making it unclear, until recently, whether the Red Sea is truly analogous. Recent work suggests that the main morphological differences between the Red Sea Rift (RSR) and other mid-ocean ridges are due to the presence and movement of giant, submarine salt flows, which blanket large portions of the rift valley and thereby the oceanic crust. Using ship-based, high-resolution multibeam bathymetry of the central RSR between 16.5°N and 23°N we focus here on the RSR volcanic terrains not covered by salt and sediments and compare their morphologies to those observed along slow and ultra-slow spreading ridges elsewhere. Regional variations in style and intensity of volcanism can be related to variations in volcanic activity and mantle heat flow. The Red Sea oceanic seafloor shows typical features of mature (ultra)slow-spreading mid-ocean ridges, such as 2nd order discontinuities (overlapping spreading centres) and magma focussing in the segment centres (forming spreading-perpendicular volcanic ridges of thick oceanic crust). The occurrence of melt-salt interaction at locations where salt glaciers blanket the neovolcanic zone, and the absence of large detachment faults are unique features of the central RSR. These features can be related to the young character of the Red Sea and may be applicable to all young oceanic rifts, associated with plumes and/or evaporites. Thus, the RSR falls in line with (ultra)slow-spreading mid-ocean ridges globally, which makes the Red Sea a unique but highly important type example for initiation of slow rifting and seafloor spreading and one of the most interesting targets for future ocean research.

Breakout of squeezed stocks: dispersal of roof fragments, source of extrusive salt and interaction with regional thrust faults

AbstractWe used seven scaled physical models to explore the near‐surface structural evolution of shallowly buried, actively rising salt stocks. The models consisted of dry sand, ceramic microspheres and silicone. Previously dormant stocks rose because of lateral squeezing or pumping of salt from below. The pressure of rising salt created a dynamic bulge in the crest of the diapir, which arched the overlying roof sediments. Eventually this dynamic bulge collapsed and its overlying roof broke into rafts along subradial grabens. The rafts were dispersed outwards by shear traction of spreading salt, surmounting an upturned collar of country rock and eventually grounding at the front of the extrusive flow. Flow of salt around these stranded fragments created a lobate extrusion front, common in submarine salt sheets in the Gulf of Mexico and subaerial salt glaciers in Iran. Stock geometry, regional dip and roof density affected extrusion rates and spreading directions. Stocks leaning seaward extruded salt faster and farther than did upright stocks. Dense roofs foundered and plugged the vent, limiting surface extrusion. In tilted models, broad salt sheets spread asymmetrically downslope. Stock contents were inverted within the extruded salt sheet: successively deeper parts of the stock's core rose to the surface and overran salt extruded from the shallower parts of the diapir. As shortening continued, salt from the source layer reached the surface after being driven out by thrusting. A central thrust block, or primary indenter, moved ahead of surrounding thrust blocks, impinging against and squeezing the stock into an elliptical planform. After high shortening, secondary indenters converged obliquely into the salt stock, expelling salt from the periphery of the diapir. The models shed light on (1) the origin and fate of large rafts or carapace blocks atop allochthonous salt, (2) cuspate margins of salt sheets and (3) interaction of thrusting, diapir pinch‐off and emplacement of allochthonous salt sheets.

Salt kinematics and regional tectonics across a Permian gas field: a case study from East Frisia, NW Germany

This study presents a reconstruction of the tectonic history of an Upper Rotliegend tight gas field in Northern Germany. Tectonism of the greater study area was influenced by multiple phases of salt movement, which produced a variety of salt-related structural features such as salt walls, salt diapirs as well as salt glaciers (namakiers). A sequential 2D retro-deformation and stratal backstripping methodology was used to differentiate mechanisms inducing salt movement and to discuss their relation to regional tectonics. The quantitative geometric restoration included sedimentary balancing, decompaction, fault-related deformation, salt movement, thermal subsidence, and isostasy to unravel the post-depositional tectonic overprint of the Rotliegend reservoir rock. The results of this study indicate that reactive salt diapirism started during an Early Triassic interval of thin-skinned extensional tectonics, followed by an active diapirism stage with an overburden salt piercement in the Late Triassic, and finally a period of intensive salt surface extrusion and the formation of salt glaciers (namakiers) in Late Triassic and Jurassic times. Since the Early Cretaceous, salt in the study area has been rising by passive diapirism.

Argon broad ion beam tomography in a cryogenic scanning electron microscope: a novel tool for the investigation of representative microstructures in sedimentary rocks containing pore fluid

The contribution describes the implementation of a broad ion beam (BIB) polisher into a scanning electron microscope (SEM) functioning at cryogenic temperature (cryo). The whole system (BIB-cryo-SEM) provides a first generation of a novel multibeam electron microscope that combines broad ion beam with cryogenic facilities in a conventional SEM to produce large, high-quality cross-sections (up to 2 mm(2)) at cryogenic temperature to be imaged at the state-of-the-art SEM resolution. Cryogenic method allows detecting fluids in their natural environment and preserves samples against desiccation and dehydration, which may damage natural microstructures. The investigation of microstructures in the third dimension is enabled by serial cross-sectioning, providing broad ion beam tomography with slices down to 350 nm thick. The functionalities of the BIB-cryo-SEM are demonstrated by the investigation of rock salts (synthetic coarse-grained sodium chloride synthesized from halite-brine mush cold pressed at 150 MPa and 4.5 GPa, and natural rock salt mylonite from a salt glacier at Qom Kuh, central Iran). In addition, results from BIB-cryo-SEM on a gas shale and Boom Clay are also presented to show that the instrument is suitable for a large range of sedimentary rocks. For the first time, pore and grain fabrics of preserved host and reservoir rocks can be investigated at nm-scale range over a representative elementary area. In comparison with the complementary and overlapping performances of the BIB-SEM method with focused ion beam-SEM and X-ray tomography methods, the BIB cross-sectioning enables detailed insights about morphologies of pores at greater resolution than X-ray tomography and allows the production of large representative surfaces suitable for FIB-SEM investigations of a specific representative site within the BIB cross-section.

Fluid distribution in grain boundaries of natural fine-grained rock salt deformed at low differential stress (Qom Kuh salt fountain, central Iran): Implications for rheology and transport properties

We used a combination of broad ion beam cross-sectioning and cryogenic SEM to image polished surfaces and corresponding pairs of fractured grain boundaries in an investigation of grain boundary microstructures and fluid distribution in naturally deformed halite from the Qom Kuh salt glacier (central Iran). At the scale of observations, four types of fluid-filled grain boundary can be distinguished by morphology (from straight to wavy), thickness (from 5000 to 50 nm) and the presence of fluid inclusions. The mobility of the brine is shown after cutting the inclusions by broad ion beam (BIB) in vacuum and fine-grained halite forms efflorescence and precipitates on internal walls of inclusions. At cryogenic temperature, grain boundary brine is shown either as continuous film or in isolated inclusions. The halite–halite grain boundary between isolated fluid inclusions is interpreted to have formed by fluid-assisted grain boundary healing. Preliminary experiments on the samples at shear stress conditions of natural salt glacier show very slow strain rates (7.4 × 10−10 s−1 and 1 × 10−9 s−1), which are less than expected for pressure solution creep. Both microstructures and deformation experiments suggest interfacial energy-driven grain boundary healing and therefore rendering inactive the pressure solution creep in our samples. This result disagrees with previous microstructural studies of the same sample, which showed microstructural evidence for pressure solution (and dislocation creep). Different explanations are discussed, which imply that both healing and reactivation of grain boundaries are important in salt glaciers, leading to heterogeneous distribution of deformation mechanisms and strain rates in both space and time.

Submarine ‘salt glacier’ of Northern Tunisia, a case of Triassic salt mobility in North African Cretaceous passive margin

Abstract Stratigraphical, sedimentological and structural data and a Bouguer gravity map of Medjez-El-Bab (MEB) in Northern Tunisia are used to illustrate a Cretaceous example of salt extrusion on a passive continental margin. Located just south of the Teboursouk thrust front (a preferential décollement surface used by the continuous Tertiary shortening in this area), the MEB structure is a simple N40°E box anticline. Removing the two Tertiary foldings (Eocene and Miocene) leads to the exposure of the original feature of a simple submarine ‘salt glacier’. The Triassic salt rocks appear as an Albian interstratified body between two Cretaceous series with stratigraphic normal polarity, suggesting a bedding parallel extrusion (at the sediment–water interface) of the Triassic salt in Cretaceous times. The formation of such salt extrusions are associated with extensional faulting (probably both in the cover and basement), the presence of a slope and basinwards salt flow. This scenario is similar to the allochthonous salt described in other salt provinces, characterizing passive margins.

Evolution of salt structures during extension and inversion of the Offshore Parentis Basin (Eastern Bay of Biscay)

Abstract The Late Jurassic–Cretaceous Parentis Basin (Eastern Bay of Biscay) illustrates a complex geological interplay between crustal tectonics and salt tectonics. Salt structures are mainly near the edges of the basin, where Jurassic–Lower Cretaceous overburden is thinner than in the basin centre and allowed salt anticlines and diapirs to form. Salt diapirs and walls began to rise reactively during the Late Jurassic as the North Atlantic Ocean and the Bay of Biscay opened. Some salt-cored drape folds formed above basement faults from the Upper Jurassic to Albian. During Albian–Late Cretaceous times, passive salt diapirs rose in chains of massive salt walls. Many salt diapirs stopped growing in the Mid-Cretaceous when their source layer depleted. During the Pyrenean orogeny (Late Cretaceous–Cenozoic), the basin was mildly shortened. Salt structures absorbed almost all the shortening and were rejuvenated to form squeezed diapirs, salt glaciers and probably subvertical welds, some of which were later reactivated as reverse faults. No new diapirs formed during the Pyrenean compression, and salt tectonics ended with the close of the Pyrenean orogeny in the Middle Miocene. Using reprocessed industrial seismic surveys, we document how salt tectonics affected the structural evolution of this offshore basin largely unknown to the international audience.

About this title ‐ Salt Tectonics, Sediments and Prospectivity

In this timely volume, geoscientists from both industry and academia present a contemporary view of salt at a global scale. The studies examine the influence of salt on synkinematic sedimentation, its role in basin evolution and tectonics, and ultimately in hydrocarbon prospectivity. Recent improvements in seismic reflection, acquisition and processing techniques have led to significant advances in the understanding of salt and sediment interactions, both along the flanks of vertical or overturned salt margins, and in subsalt plays such as offshore Brazil. The book is broadly separated into five major themes covering a variety of geographical and process-linked topics. These are: halokinetic sequence stratigraphy, salt in passive margin settings, Central European salt basins, deformation within and adjacent to salt, and salt in contractional settings and salt glaciers.

Gravity analysis of salt structures. An example from the El Kef-Ouargha region (northern Tunisia)

ABSTRACT Triassic outcrops in the Atlassic zone of northern Tunisia may be modelled in two ways: salt bodies piercing through Cretaceous terrains or Triassic salt flows stratified within an Albian series. Both models find support from gravity data and are debatable. To evaluate the mass distribution changes with depth, the Bouguer anomaly of the El Kef‐Ouargha region was successively decomposed into regional and residual components to construct multiple pseudo‐depth slices and apparent density maps. Analyses of gravity lows clearly show a vertical continuity of less dense materials below the Triassic salt outcrops. These features can be explained by salt diapirism during Mesozoic and Cenozoic. Further, gravity data tend to indicate less dense materials below Aptian outcropping in Jebel Aite (Oued Bou Adila); thus suggesting Triassic materials occurring at depth. In addition, dense entities were recognized under Mio‐Pliocene and Quaternary deposits, which are thought to correspond to Cretaceous paleoshoals currently collapsed by non‐outcropping faults. Our findings lend support to a diapir model intruding overburden rather than the salt glacier model stratified in the Albian series proposed by some authors as the genetic structural model for Triassic material‐bearing series in the north of Tunisia.

Surficial deposits on salt diapirs (Zagros Mountains and Persian Gulf Platform, Iran): Characterization, evolution, erosion and the influence on landscape morphology

The surfaces of salt diapirs in the Zagros Mountains are mostly covered by surficial deposits, which significantly affect erosion rates, salt karst evolution, land use and the density of the vegetation cover. Eleven salt diapirs were selected for the study of surficial deposits in order to cover variability in the geology, morphology and climate in a majority of the diapirs in the Zagros Mountains and Persian Gulf Platform. The chemical and mineralogical compositions of 80 selected samples were studied mainly by X-ray powder diffraction and X-ray fluorescence. Changes in salinity along selected vertical profiles were studied together with the halite and gypsum distribution. The subaerial residuum formed from minerals and rock detritus released from the dissolved rock salt is by far the most abundant material on the diapirs. Fluvial sediments derived from this type of residuum are the second most common deposits found, while submarine residuum and marine sediments have only local importance. The mineralogical/chemical composition of surficial deposits varies amongst the three end members: evaporite minerals (gypsum/anhydrite and minor halite), carbonates (dolomite and calcite) and silicates-oxides (mainly quartz, phyllosilicates, and hematite). Based on infiltration tests on different types of surficial deposits, most of the rainwater will infiltrate, while overland flow predominates on rock salt exposures. Recharge concentration and thick accumulations of fine sediment support relatively rich vegetation cover in some places and even enable local agricultural activity. The source material, diapir relief, climatic conditions and vegetation cover were found to be the main factors affecting the development and erosion of surficial deposits. A difference was found in residuum type and landscape morphology between the relatively humid NW part of the studied area and the arid Persian Gulf coast: In the NW, the medium and thick residuum seems to be stable under current climatic conditions. Large sinkholes and blind valleys with sinking streams are common. On other diapirs, the original thick residuum is undergoing erosion and the new morphology is currently represented by salt exposures and badland-like landscapes or by fields of small sinkholes developed in the thin residuum. Models for evolution of the subaerial residuum and the diapir landscape/morphology are described in this paper. While the thick residuum with vegetation has very low erosion rates, the salt exposures and thin residuum are eroded rapidly. During wet periods (e.g. early Holocene), the diapirs rose and salt glaciers expanded as the influx of salt mass was much faster compared to erosion. After the onset of an arid climate, c. 6 ka BP, the rising of the some diapir surfaces decreased or even reversed due to acceleration of erosion thanks to vegetation degradation and changes in the residuum type and thickness.

Salt terrains of Iran

Salt only survives at outcrop in desert climates, and southern Iran has more than its share of salt mountains created by rising diapirs. With their white salt cliffs and creeping salt glaciers, these constitute amazing landscapes with collapsing dolines that feed into spectacularly decorated caves.

Subsurface seismic record of salt glaciers in an extensional intracontinental setting (Late Triassic of northwestern Germany)

Research Article| November 01, 2007 Subsurface seismic record of salt glaciers in an extensional intracontinental setting (Late Triassic of northwestern Germany) Markus Mohr; Markus Mohr 1Geological Institute, RWTH Aachen University, Wüllnerstrasse 2, 52056 Aachen, Germany Search for other works by this author on: GSW Google Scholar John K. Warren; John K. Warren 2Shell Chair in Carbonate Studies, Sultan Qaboos University, Muscat, Oman Search for other works by this author on: GSW Google Scholar Peter A. Kukla; Peter A. Kukla 3Geological Institute, RWTH Aachen University, Wüllnerstrasse 2, 52056 Aachen, Germany Search for other works by this author on: GSW Google Scholar Janos L. Urai; Janos L. Urai 3Geological Institute, RWTH Aachen University, Wüllnerstrasse 2, 52056 Aachen, Germany Search for other works by this author on: GSW Google Scholar Anton Irmen Anton Irmen 4Gaz de France Produktion Exploration Deutschland GmbH, Lingen (Ems), Germany Search for other works by this author on: GSW Google Scholar Author and Article Information Markus Mohr 1Geological Institute, RWTH Aachen University, Wüllnerstrasse 2, 52056 Aachen, Germany John K. Warren 2Shell Chair in Carbonate Studies, Sultan Qaboos University, Muscat, Oman Peter A. Kukla 3Geological Institute, RWTH Aachen University, Wüllnerstrasse 2, 52056 Aachen, Germany Janos L. Urai 3Geological Institute, RWTH Aachen University, Wüllnerstrasse 2, 52056 Aachen, Germany Anton Irmen 4Gaz de France Produktion Exploration Deutschland GmbH, Lingen (Ems), Germany Publisher: Geological Society of America Received: 20 Sep 2006 Revision Received: 08 Jun 2007 Accepted: 14 Jun 2007 First Online: 09 Mar 2017 Online ISSN: 1943-2682 Print ISSN: 0091-7613 The Geological Society of America, Inc. Geology (2007) 35 (11): 963–966. https://doi.org/10.1130/G23378A.1 Article history Received: 20 Sep 2006 Revision Received: 08 Jun 2007 Accepted: 14 Jun 2007 First Online: 09 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn MailTo Tools Icon Tools Get Permissions Search Site Citation Markus Mohr, John K. Warren, Peter A. Kukla, Janos L. Urai, Anton Irmen; Subsurface seismic record of salt glaciers in an extensional intracontinental setting (Late Triassic of northwestern Germany). Geology 2007;; 35 (11): 963–966. doi: https://doi.org/10.1130/G23378A.1 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGeology Search Advanced Search Abstract In the Northwest German Basin of Central Europe, Late Triassic interaction of normal faulting and salt diapirism during regional extension in subsalt basement locally initiated lateral flow of surface-piercing salt in namakiers (salt glaciers). Using seismic sections and variance attribute maps derived from high-resolution three-dimensional seismic data, we show that when a syndepositional fault cuts a near-emergent diapir crest, the caprock carapace was breached, opening a pathway for salt extrusion. The fault escarpment and the adjacent fault-induced depression allowed focused gravity-driven downward flow of salt across the land surface (a namakier) and its subsequent preservation and encasement in continental (arid redbed) sediments. Geodynamically there is an apparent distinction between the compressional setting of modern namakiers in the arid deserts of Iran and the fault-intersected extensional setting of stacked Keuper namakiers. Stacked namakiers preserved in thicknesses that are seismically resolvable are interpreted to indicate hyperarid conditions in Keuper time. The climate was typical of the highly continental Late Triassic Pangaean supercontinent as it rifted and sagged to form the incipient Atlantic Ocean. You do not have access to this content, please speak to your institutional administrator if you feel you should have access.