The age and origins of arid adaptations and gypsum endemism in Nyctaginaceae inferred using relaxed molecular dating. Islands of exposed gypsum are scattered throughout the Chihuahuan Desert region of northern Mexico and the southwestern US. Although gypsum forms a hard crust and is generally low in nutrients, many plant species have adapted to grow on this substrate, with some fully restricted to it. Morphological, phylogenetic, and biogeographic evidence suggest that clades of gypsum endemics exist, and that some of these groups may have originated as early as the late Miocene. If true, these endemics must have persisted throughout the Pleistocene full-glacial periods, when the Chihuahuan Desert was largely replaced by grassland and savanna. The flowering plant family Nyctaginaceae is unusually rich in gypsum endemics, with 10 species in four genera in the family restricted to gypsum in the Chihuahuan Desert. In two of these genera, Anulocaulis and Acleisanthes , morphologically distinct and geographically widespread clades of multiple gypsum endemic species have evolved. In contrast, gypsum endemic taxa in the genera Abronia and Mirabilis are narrowly distributed and morphologically similar to taxa that grow off of gypsum. To determine whether gypsum endemism evolved within Nyctaginaceae before the Pleistocene, and to determine if gypsum endemism originated simultaneously in all lineages, we undertook molecular dating analyses of Caryophyllales. Because nyctages lack a reliable fossil record, broad taxon sampling of Caryophyllales is necessary for incorporating reasonable fossil calibration points.
Naturally occurring gypsum has a long tradition as a building material, with first use-cases dating back to the Neolithic age. Today, it is a crucial component in plasterboard, favoured by builders across the world for its ease of use and relatively low weight. There are only a few manufacturers in the world who can supply complete plants for the manufacture of plasterboard. Since the s particularly one OEM has relied on Renold inverted tooth chains and sprockets to run some of the critical parts of its production lines.
The bespoke chains have been specially developed to suit the needs of the gypsum plasterboard manufacturing process. To reach their daily production goals, manufacturers need to ensure that every step of the production process runs as planned.
The ESR dating of gypsum deposits at Mammoth Cave in Kentucky was first noted as a possibility (Ikeya ). Stratigraphic marine gypsum crystals have been.
Our data implies an early onset of hyper- aridity in the core region of the Atacama Desert, interrupted by wetter but probably still arid periods. The apparent conflict with interpretation that favour a later onset of hyper- aridity can be reconciled when the climatic gradients within the Atacama Desert are considered.
Neogene fluvial landscape evolution in the hyperarid core of the Atacama Desert
Taking the necessary measures to maintain employees’ safety, we continue to operate and accept samples for analysis. Pretreatment — It is important to understand the pretreatment applied to samples since they directly affect the final result. You are welcome to contact us to discuss the pretreatment or request that we contact you after the pretreatment and prior to dating.
gypsum mining in nagoreGypsum mining in nagore Gypsum Crusher Ritchie Bros Gypsum mining has a long history in kansas dating to the mid to lates.
InspectAPedia tolerates no conflicts of interest. We have no relationship with advertisers, products, or services discussed at this website. Here we illustrate identifying stamps, labeling, paper imprints, and other details that can help identyify specific drywall or gypsum board products. These markings can help forming an estimate of building age and also help identify drywall products that might contain asbestos.
This article series discusses the identification and history of both modern and older interior building surface materials such plaster and lath, Beaverboard, and Drywall – materials that were used to form the usually non-structural surface of building interior ceilings and walls. Our page top photo shows hand-split wooden lath backing for a plaster interior wall.
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Uranium-series dating of gypsum speleothems: methodology and examples. International Journal of Speleology, 39(1), Bologna (Italy). ISSN
To browse Academia. Skip to main content. Log In Sign Up. Download Free PDF. Uranium-series dating of gypsum speleothems: methodology and examples International Journal of Speleology, Laura Sanna. Stein-Erik Lauritzen. Silviu Constantin. Paolo Forti.
Drywall (Gypsum) Diversion
Recent analyses have proven that a traditionally-made gypsum plaster is consistently employed on these figures and on archaeological stuccoes. This figure also displays integrated restoration of the first half of the twentieth century, including additions in a more refined gypsum, and modern pigments some of the reds and synthetic ultramarine blue. Public Domain.
due to the presence of gigantic gypsum crystals. The first reports of these cavities date back to the early twentieth century (Degoutin ;.
T his point is found throughout the southern Great Basin and the southern Colorado Plateau into the southwestern region and into northern Sonora and northern Baja California, Mexico. This type was reported at the La Playa site in northern Sonora, Mexico. Harrington excavated the Gypsum Cave site in Nevada. These points were named for this site. Since that time they have been re-defined by Robert H.
Franks in and Richard Homer in
Meet a loving partner in Gypsum today.
Mentioned in? References in periodicals archive? Analysing gypsum mortar connecting that slab to the bedrock allowed them to determine its age, dating it to AD. Researchers date discovery of Christ’s tomb in Jerusalem to Roman era.
Uranium series dating of speleothems show ages ranging from gypsum karstic caves in arid climates (Calaforra et al., ), where.
This is a private group. To join you must be a registered site member and request group membership. Purpose Understand the origin and evolution of gypsum endemic floras worldwide from a phylogenetic perspective. Scope This WP will focus on those regions with better background floristic knowledge of gypsum endemic plants, namely Spain, the Chihuahuan Desert, Turkey, Iran and Australia. Task 2. We will start by doing a thorough literature and web database including GenBank review, searching all available information for the different floras under study.
Uranium-series dating of gypsum speleothems: methodology and examples
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It is a very soft mineral and it can form very pretty, and sometimes extremely large colored crystals. Massive gypsum rock forms within layers of sedimentary rock, typically found in thick beds or layers. It forms in lagoons where ocean waters high in calcium and sulfate content can slowly evaporate and be regularly replenished with new sources of water.
While the majority of gypsum produced in North America is used to manufacture wallboard, gypsum can also be used:. Gypsum is a mineral found in sedimentary rock formations in a crystalline form known as calcium sulfate dihydrate. One hundred pounds of gypsum rock contains approximately 21 pounds or 10 quarts of chemically combined water.
Gypsum rock is mined or quarried and then crushed. The calcined gypsum or hemihydrate becomes the base for gypsum plaster, wallboard and other gypsum products. To produce wallboard, calcined gypsum is mixed with water and additives to form a slurry which is fed between continuous layers of paper on a board machine. As the board moves down a conveyer line, the calcium sulfate recrystallizes or rehydrates, reverting to its original rock state.