This study describes and interprets the primary deposition and diagenetic formation of the evaporite minerals gypsum, anhydrite and halite in the coastal and interdunal evaporation settings of sabkhas and saline pans in Egypt and Saudi Arabia. The high evaporation, low inflow of groundwater, rainfall, in addition to continental and marine floodings, and restriction of the evaporation settings allow the deposition of gypsum at salinities exceeding 120‰, anhydrite at 200‰–220‰ and halite >220‰. In the saline pans, gypsum and halite are precipitated freely from the brine column according to the brine salinity. Gypsum is deposited on the floor of saline pans as free, upward growing swallowtail, fibrous and rosette crystals, whereas halite crystallizes at the brine surface as rafts and cumulates, and on the floor of the pans as chevrons and cornets. In the sabkha areas, gypsum and anhydrite are formed by displacive, inclusive and replacive growth below the sediment surface of the sabkhas, whereas halite is precipitated as clear, mosaic cement and as efflorescent crystals between the sediment matrix grains. The saline pans are characterized by the deposition of ~30 cm thick gypsum and halite layers that may have thin laminae of microbial mats. The sabkhas are characterized by the occurrence of gypsum and anhydrite as nodules, enterolithic folds and random lenticular crystals, whereas halite occurs as cement and efflorescence. No recognized evaporite structures are specific to coastal or interdunal sabkhas and pans, except the occurrence of marine shells in the coastal evaporation settings and the dominance of clastic materials in the interdunal evaporation settings. Sinkholes are formed in the Red Sea and Arabian Gulf sabkhas due to the dissolution of underlying gypsum and/or halite layers by ascending, low-salinity groundwater and/or seawater seepage. The results of this chapter allow the recognition of the specific structures and textural characteristics of the sabkhas and saline pans that may help in the interpretation of similar features in the recent and ancient rock records.

The Stuttgart Formation (traditionally called the Schilfsandstein) in the Germanic Basin (or Central European Basin) is a sand-rich episode representing the Mid-Carnian Episode within the gypsum-rich clayey semi-arid Keuper facies. That regional Mid-Carnian Episode is now recognized to be a manifestation of a significant global disruption of Earth's climate-ocean-biological system during the early Late Triassic. In order to provide an accurate time frame and means for high-resolution correlations among continental and marine records, we obtained a composite magnetostratigraphy spanning the entire Carnian from three boreholes in the Germanic Basin. This composite shows a good consistency with earlier published magnetostratigraphy results from South China and enables the construction of a complete Carnian polarity time scale. The upper Carnian (Tuvalian substage) portion implies that: (1) The lower quarter of the Tuvalian is dominated by a reversed-polarity magnetozone; (2) The termination of the Yangtze Platform is coeval with deposition of the Stuttgart Formation in the Germanic Basin; (3) The radiolarian-rich green-colored clay horizon of the Pignola-2 section in south Italy that is below a volcanic ash bed dated as ca. 231 Ma correlates with the D pulse of siliciclastics in Dibona section of north Italy in the middle of the Tuvalian; (4) The upper three-fourths of the Tuvalian is a major normal-polarity-dominated magnetozone; and this interval correlates with the basal E1-E6 portion of the Newark magnetic polarity reference series according to the favored correlation option; (5) The base of the Arnstadt Formation of the Germanic Basin, which had been traditionally assigned as the Carnian/Norian boundary, instead begins within the lower portion of Newark reversed-polarity zone E8r of earliest Norian according to the favored age model, although pending future verification; (6) The polarity patterns of portions of the upper Carnian from the western Tethys sections of Lower Trench at Silická Brezová in Austria and Pizzo Mondello in Italy are verified. This Carnian composite is an enhanced polarity time scale for calibration of other global Carnian successions and events, such as the appearance of the earliest dinosaurs in fossiliferous beds of South America.

As a result of recent extensive palaeontological investigations large parts of the Keuper in the North German Basin are now dated by means of palynomorph and conchostracan biostratigraphy. The progress in biostratigraphic dating has contributed to an improved correlation of the Keuper with the chronostratigraphic standard of the Upper Triassic. Evidence for the presence of all Upper Triassic stages and substages points to largely continuous deposition of the Keuper in the North German Basin. Significant stratigraphic gaps arc associated with the Schilfsandstein Unconformity (base Stuttgart Formation), Early Cimmerian Unconformity (base Arnstadt Formation) and Rhaetian Unconformity (intra-Exter Formation) but are restricted to intra-basinal swells and basin margin areas. Local stratigraphic gaps resulting, for example, from fluvial incision are also present. In future, a clear distinction should be made between significant unconformities and local stratigraphic gaps in Keuper successions. The improved biostratigraphy also enables precise dating of major facies changes. The Muschelkalk/Keuper and Steinmergelkeuper/Rhaetian facies changes are strongly diachronous from north to south and west to east respectively. Other facies changes, such as that at the base of the Stuttgart Formation, are only slightly diachronous in some parts of the basin. As a consequence, diachronous lithostratigraphic boundaries resulting from such facies changes should be taken into consideration in stratigraphic schemes.

Field and petrographic studies of recent supratidal sabkhas and ponds, and a solar salt works, in Saudi Arabia and Egypt have documented the formation of distinctive surface sedimentary structures that have resulted from microbial activity and abiological physical processes. Microbially induced sedimentary structures (MISS) dominate the permanent and ephemeral parts of supratidal ponds of Al Zeeb sabkha, Saudi Arabia and halite crystallization ponds in salt works, west of Alexandria, Egypt. They are varied and include gas bubbles, blisters, wrinkles, pinnacles, cones, and polygonal folds (petees) induced by epibenthic microbial mats. Physically induced sedimentary structures dominate the emergent areas surrounding the ponds, as well as the supratidal sabkhas in Al Zeeb and Ras Shukeir areas. They include polygonal cracks and different types of tepees. The sediments of the microbial-induced structures are composed of green and brown microbial filaments that entrap and bind lenticular and clastic gypsum, or form nucleation sites for halite and/or grass-like gypsum crystals. The sediments of the physically induced structures are composed of halite-cemented siliciclastic sand and mud, or bottom-nucleated chevron and cornet halite crystals. The results of this study indicate that microbial and physical structures co-exist due to local factors, especially topography, brine recharge, salinity, microbial activity, and history of the supratidal sabkha and pond. The importance of the local interplay of these conditions indicates that it will be difficult to interpret sedimentary successions in fossil sabkhas and their general depositional environment if only limited sections are available for study.

Armoured mud balls were observed after rainfall and a short flood in the otherwise dry Xiaohe (small river) valley of Guanling County, Guizhou Province, South China, approximately 30km southwest of Guanling City. Armoured mud balls are most common in semiarid climates, but rather unusual in a humid climate as in Guizhou. A number of well-rounded mud balls, 2–20cm in diameter, were found lying on the gravel of the Xiaohe gully floor. The mud balls consist of sticky, light brown and slightly mottled clay without carbonate content. The surfaces of the mud balls were studded with rims of sand- or gravel-size limestone clasts, collected during bedload transport, as is typical for armoured mud balls. The mud balls originated from alluvial mudstone deposits of the valley floor and cliff that are most likely derived from the weathering and karstification of bedrock limestones. Such mudstones with high clay content seem to be especially well suited for forming armoured mud balls. As flood events are rather common in the area, the formation of armoured mud balls should be very frequent in the Xiaohe valley and similar valleys nearby, giving the possibility for further and more detailed studies. To the best of our knowledge this is the first description of armoured mud balls in China.

The index species of the basal Norian monospecific “Palaeolimnadia schwanbergensis Zone” does not belong to that genus or species. Instead, it is a primitive Shipingia species (transitional to Palaeolimnadia) here named Shipingia weemsi n. sp. The type specimen of Palaeolimnadia schwanbergensis Reible comes from the "Berggipsschichten" of Iphofen of early Tuvalian age. It is a distinctly different species closely related to an undescribed Palaeolimnadia of the upper Schilfsandstein. Therefore, the uppermost Tuvalian Laxitextella freybergi"Palaeolimnadia schwanbergensis" Zone and the basal Norian monospecific "Palaeolimnadia schwanbergensis" Zone of Kozur and Weems (2010) must be re-named the Laxitextella freybergi-Shipingia weemsi Zone and the Shipingia weemsi Zone, respectively. In the central basin facies of the Germanic Basin, the Laxitextella freybergiShipingia weemsi Zone occurs in the uppermost Heldburg Gypsum Member of the Weser Formation (uppermost Tuvalian) and the S. weemsi Zone occurs in the basal Arnstadt-Formation (basal Norian). The occurrence of S. weemsi on both sides of the Heldburg Gypsum Member of the Weser Formation-Arnstadt Formation lithostratigraphic boundary, as well as the gradual change of the conchostracan faunas from the late Tuvalian Coburg Sandstone (Laxitextella freybergi Zone) through the latest Tuvalian Heldburg Gypsum Member (Laxitextella freybergi-Shipingia weemsi Zone) to the basal Lacian Arnstadt Formation (Shipingia weemsi Zone), indicates that there is not a long time-gap within the central basin facies at the "Early Cimmerian Unconformity" ("Altkimmerische

The Kupferschiefer of northern central Europe is not only one of the largest sediment-hosted accumulations of copper ores worldwide (largest 1% of deposits with > 60 Mt contained Cu) but has also one of the longest continuously documented mining histories, starting from at least 1,199 A.D. in the Mansfeld district of Germany. Kupferschiefer ores are currently mined in Poland from several large underground mines with active near-mine exploration and possible downdip extensions at a planning stage. Kupferschiefer mines in the Mansfeld and Sangerhausen districts of Germany had been largely exhausted by 1990 but a new exploration campaign is currently targeting a major deep Kupferschiefer resource near Germany's eastern border with Poland.The Cu-rich part of the Kupferschiefer mineralization is dominated by chalcocite, chalcopyrite, and bornite and is hosted by several rock types including footwall sandstone and conglomerate, black shale, carbonate rocks in the immediate hanging wall, and anhydrite even higher in the hanging wall. Orebodies can range in thickness from 0.3 m, contained largely within the black shale of the Kupferschiefer sensu stricto, up to more than 50 m, where sublevel stoping, backfilling, and pillar mining reflect the pervasive mineralization. The ore zone can occur at various stratigraphic levels from (1) as low as some 35 m below the Kupferschiefer sensu strict, to (2) within and immediately adjacent to the black shale unit, to (3) several tens of meters above the base of the Zechstein limestone. Economic mineralization also occurs locally where no black shale has been deposited at all, for example, above Weissliegend sand dunes at the basin margin of the Kupferschiefer Sea that were never covered by the black euxinic mud. Ore textures include disseminated ores, disseminated replacement of diagenetic and framboidal pyrite, crosscutting and bedding parallel veinlets, impregnation and replacement ore of carbonate and anhydrite cements, replacement of fossil shells, and even replacement of detrital feldspar and feldspar in lithic clasts.All copper deposits share a marked metal and ore mineral zonation pattern adjacent to a major secondary redox front, the so-called Rote Faule. This three-dimensionally, roughly hemispherically zoned mineralization system is transgressive and locally even steeply crosscutting to stratigraphy. It grades from an Fe3+ zone (hematite), through a locally developed precious metal (Au, Pt, Pd) zone, an always redox-proximal Cu zone (chalcocite, bornite, chalcopyrite), a locally overlapping Pb and Zn zone, into a distal Fe2+ zone of preore, commonly framboidal or early diagenetic pyrite. The oxidized part of the zoned orebodies commonly originates from permeable zones such as fault structures or sand dunes, which might have acted as valves through the relatively impermeable Kupferschiefer.In general, the Kupferschiefer mining districts occur exclusively within an arcuate belt that is situated above basement rocks of magmatic arc origin, the Mid-European Crystalline High, typically at the intersections with major NW-SE-and NNE-SSW-trending fault structures. Local and regional studies have shown that regional metal distribution, orebody geometry, and metal grades are largely structurally controlled, although divergent opinions were originally expressed as to the timing of metal introduction via these conduits. An absolute age of ca. 255 Ma is generally accepted as the sedimentation age for the "Kupferschiefer" black shale. However, recent paleomagnetic age dating of mineralization at Sangerhausen has revealed late epigenetic mineralization ages of 149 and/or 53 Ma. The results argue for a new metallogenic model, which involves two major epigenetic pulses of metal introduction to the Kupferschiefer ores as impregnations, replacements, and subsequent veins and breccias.A holistic understanding of the Central European Basin, which hosts the Kupferschiefer ores in its lower part of the stratigraphy, from the basin's origin in the Late Carboniferous to the Tertiary, and particularly the various related extensional and compressive tectonic events helps to put the individual stages of Kupferschiefer mineralization into a European plate tectonic perspective. The time span from Late Jurassic to Mid-Cretaceous was a period of major crustal rearrangement with the break-up of Pangea and the potential for the remobilization of major pulses of metalliferous brines. Both the main quantity of the Kupferschiefer ores and the giant Mississippi Valley-type (MVT) Pb-Zn ores of Upper Silesia appear to have formed at this stage. The younger, Tertiary, mineralizing event is also noted in both base metal provinces and was probably, again, related to crustal movement that involved metalliferous fluid flow. Additionally, this period was accompanied by magmatic pulses in the wider area of the Kupferschiefer metalliferous belt. Locally, late vein-type Co-Ni-rich mineralization, upgrading preexisting impregnation and replacement ores, gives evidence for this latest hydrothermal event, for example, in the German mining districts of Spessart/Rhon and Richelsdorf.

The Stuttgart Formation (Schilfsandstein) is approximately 50 m thick in Thuringia, representing deposition during the "Mid-Carnian Wet Intermezzo". Stratigraphically it occurs between the Grabfeld and Weser formations, which formed under arid conditions. It comprises NNE-SSW-trending elongate, anastomosing channelized sand-rich bodies with erosional bases (channel belts) that are several kilometres wide and pass laterally into predominantly mudstones deposited in interfluve areas. The source area of these clastics was the uplifted Norwegian Caledonides. Muddy interfluve facies is dominant in exposures in Thuringia, Central Germany.The Lower Stuttgart Formation has an unconformable base that is locally overlain by metre-thick "Basal Beds". These consist of grey mudstones and thin sandstones deposited under humid conditions in predominantly shallow brackish water environments after a marine ingression via the Eastern Carpathian/Upper Silesian Gate. The following 30-40 m-grey, fine-grained sandstones, siltstones and mudstones were deposited in fluvial environments in channel belts and interfluve areas under humid conditions. These are followed by predominantly reddish mudstones and sandstones of mainly fluvial origin, deposited under somewhat drier conditions with seasonal droughts. The Upper Stuttgart Formation may be more than 16 m thick: it comprises reddish and grey sandstones and mudstones that were mostly deposited in lake delta settings by recurring flash floods. During the deposition of this unit climate was weakly humid with less prominent seasonal draughts.The modern Ganga Plain of India is an analogue for the depositional setting of the Stuttgart Formation. Climatic conditions in Ganga Plain are humid monsoonal with seasonal droughts and roughly comparable with those interpreted for Mid-Carnian times in Germany. The sandy deposits of incised channel belts and channels and muddy deposits of interfluve areas in the Ganga Plain are comparable with the sandstonedominated channelized facies and mudstone dominated interfluve facies of the Stuttgart Formation, respectively. Crown Copyright (C) 2010 Published by Elsevier B.V. All rights reserved.

The Middle Carnian Wet Intermezzo (MCWI) of the Stuttgart Formation (Schilfsandstein) and age-equivalent strata of the northwestern Tethys occurred entirely within equivalents of the upper subzone of the Austrotrachyceras austriacum ammonoid zone of the late Julian. Its duration is estimated to be only about 0.7-0.8 myr. In both the Germanic Basin and the northwestern Tethys, the warm climate during the MCWI was characterized by a rate of precipitation that exceeded somewhat the evaporation but was not so great as to be pluvial. The MCWI was related to the atmospheric circulation of a megamonsoonal system that was characterized by strong, moisture-laden, northwesterly flowing trade winds that rose as they reached the estimated 2000-3000 m high eastern shoulder uplift of a huge rift causing them to drop an extraordinary amount of rain. This eastern shoulder uplift lay within the Caledonides of modern day western Scandinavia. This region only, between 30 and 50 degrees N palaeolatitude, had a truly pluvial climate, and the huge amounts of fresh water dropped there transported large amounts of siliciclastics from this rift-shoulder uplift southward into the Germanic Basin.Before deposition of the siliciclastics an early Julian eustatic sea-level fall caused widespread erosion in the Germanic Basin. In the later part of late Julian, a transgression from the eastern gates with the concurrent strong fresh water influx from the north flooded the centre of the northern Germanic Basin with a shallow brackish sea in which the Osterhagen Horizon (Basisschichten) of the lower Stuttgart Formation was deposited. In the upper Osterhagen Horizon the salinity rapidly decreased from mesohaline through mio- and oligohaline to fresh water levels. In southern Germany the Basisschichten formed entirely within fresh water or very low salinity brackish environments. Later, a slight subsidence of the southwestern Germanic Basin shifted the main outflow of fresh water toward the southwestern end of the basin, creating local brackish conditions in the northern marginal part of the northwestern Tethys (e.g. in the Lunz Beds). During this time interval, tidal influence also can be found in the Stuttgart Formation deposited in palaeoestuaries of the southwestern Germanic Basin adjacent to the Tethys. The very strong fresh water influx from the north, however, prevented these estuaries from developing a strongly elevated salt content, so that only fresh water to oligohaline brackish faunas are found there such as the Eberstadt bivalve-conchostracan fauna.At the base of the Tuvalian, the megamonsoonal system either disintegrated or else the trade winds shifted their principal flow direction. This caused the climate within the Germanic Basin and in the nearby northwestern Tethys Sea to become arid again as it had been before the deposition of the Stuttgart Formation. These changes in the atmospheric circulation patterns also terminated the pluvial climatic regime to the north along the Scandinavian eastern rift-shoulder uplift. This in turn ended the transport of huge amounts of siliciclastics from this region southward into the Germanic Basin and ended the deposition of the Schilfsandstein. After this, the hypersaline sabkha and playa sedimentation of the Weser Formation began, which was accompanied by some minor marine ingressions in the southwestern Germanic Basin. (c) 2009 Elsevier B.V. All rights reserved.