Gypsum

In Great Britain, gypsum karst is widespread in the Late Permian (Zechstein) gypsum of north-eastern England. Here and offshore, a well-developed palacokarst with large breccia pipes was formed by dissolution of the underlying Permian gypsum. Farther south, around Ripon, the same rocks are still being dissolved, forming an actively evolving phreatic gypsum-maze cave system. This is indicated by the presence of numerous active subsidence hollows and sulphate-rich springs. In the English Midlands, gypsum karst is locally developed in the Triassic deposits south of Derby and Nottingham. Where gypsum is present, its fast rate of dissolution and the collapse of overlying strata lead to difficult civil-engineering and construction conditions; these can be further aggravated by water abstraction. Salt (halite) occurs within British Permian and Triassic strata, and has a long history of exploitation. The main salt fields are in central England and the coastal areas of northwest and northeast England. In central England, saline springs indicate that rapid, active dissolution occurs that can cause subsidence problems. In the past, subsidence was aggravated by shallow mining and the uncontrolled extraction of vast amounts of brine. This has now almost stopped, but there is a legacy of unstable buried salt karst, formed by both natural and induced dissolution. The buried salt karst occurs at depths ranging from about 40 m to 130 m; above these depths, the overlying strata are foundered and brecciated. In the salt areas, construction and development are hampered by both abandoned mines and by natural or induced brine runs, with their associated unstable ground.

Authorship: A. Fuchs, A. H. Cooper, I. Gans, M. Krempler, M Malpass 2015. This paper describes the provenance and restoration of the alabaster monument to Duke Ulrich in Güstrow Cathedral, Germany. The alabaster is shown to be of English provenance probably from the Chellaston area. Material was sourced from here for the restoration.

Keywords: triple oxygen isotopes gypsum hydration water relative humidity lake sediments Younger Dryas Late Glacial–Holocene transition Atmospheric relative humidity is an important parameter affecting vegetation yet paleo-humidity proxies are scarce and difficult to calibrate. Here we use triple oxygen (δ 17 O and δ 18 O) and hydrogen (δD) isotopes of structurally-bound gypsum hydration water (GHW) extracted from lacustrine gypsum to quantify past changes in atmospheric relative humidity. An evaporation isotope-mass-balance model is used together with Monte Carlo simulations to determine the range of climatological conditions that simultaneously satisfy the stable isotope results of GHW, and with statistically robust estimates of uncertainty. We apply this method to reconstruct the isotopic composition of paleo-waters of Lake Estanya (NE Spain) and changes in normalized atmospheric relative humidity (RH n) over the last glacial termination and Holocene (from ∼15 to 0.6 cal. kyrs BP...

A seismic reflection survey was carried out in Bishop Wood, Yorkshire to determine the subsurface structure and the depth to the prospective gypsum and coal measures. Four 24-channel Geodes were used with a PEG40 accelerated weight drop and 10 Hz geophones at 3 m intervals to shot a 1099 m spread.  The final depth processed section shows some reflectors which are clearly visible and is geologically consistent with borehole information in the area. A strong reflector was found at 25 to 50 m depth, multiple reflections were seen between 70 and 150 m and a strong reflector was seen at 200 to 250 m on the processed seismic section. These were tentatively interpreted as the top of Bunter sandstone, multiple gypsum horizons and the top of coal measures respectively, these observations agreed with the borehole information obtained in the area.  A southwards dipping fault was inferred in the section at approximately 600 m along the line, though this may be an artefact due to acquisition and...

We present new data about speleothems of gypsum formerly analyzed by DRX. These speleothems are located in a cave in carbonatic sandstone of the Jaizkibel Formation (of Eocene age). The sample has been analyzed by an energy dispersion microanalyzer (XPS) connected to the equipment of a scanning electron microscopy (SEM). The acicular crystals of gypsum grow on a basis of opal-A. In addition, there are traces of other elements, as C, which we attribute to organic matter from microbial mats adjoining to the speleothems.
Link: http://www.aranzadi.eus/fileadmin/webs/Publicaciones/pdfs/GREEN%20CAVE4.pdf

A field experiment was conducted at Soil Research Area of CCS Haryana Agricultural University, Hisar during the rabi season of 2000-01 with an objective to study the effect of deep tillage and gypsum application on oil and protein content of mustard. The experiment consisted of two tillage treatments [conventional tillage (CT) comprising one discing (10 cm depth) and one run of cultivator followed by planking; and deep tillage with disc plough comprising 20-25 cm sub-soiling followed by CT] and two gypsum treatments (control and gypsum @ 250 kg/ha i. e. 45 kg S/ha). The study clearly illustrates that a plough sole in a sandy loam can be alleviated by deep ploughing with disc plough and oil yield of mustard can be increased by 41% over conventional tillage practice. The addition of gypsum further increased the oil yield by 84%.

Mortars have been used for thousands of years by peoples of the Riverine Plains and along the Murray River, and these objects are still to be found near the places where people lived and worked. One such item was uncovered at the edge of Cow Creek during construction of the Koondrook Perricoota Forest Flood Enhancement Works. Close inspection of the grinding surface shows clear signs of a white material. The Murray Darling Basin has rich deposits of gypsum which was used for decoration, ceremony and a range of other purposes.
Among the Barapa Barapa people of the Central Murray River, the word for gypsum is Kow or Ghow and people clearly knew of the location of major sources of gypsum: Kow Swamp, Kow Plains and Cow Creek are three examples. This mortar would have been used to grind the gypsum for paint used in corroborees as shown in historical paintings from the region.

The karst which has developed on the widespread Mississippian gypsum-anhydrite deposits of the Canadian Maritime provinces is described. Nova Scotia and New Brunswick have large areas displaying all stages of erosion from drift covered through to cockpit karst. Caves are common, but small. Their morphological features, including certain forms that have not been reported before, are catalogued and described, and the nature of gypsum speleogenesis in the region is discussed. Cave passages are dominated by laugh๖hlen ("leaching caves"), defined in the classic German South Harz gypsum region. These forms are probably atypical and relatively rare elsewhere. It is emphasised that laugh๖hlen are the horizontal component of cave systems: it is here shown how they relate structurally and speleogenetically to (sub)vertical features that form between the karst surface and the water table. Dissolution of both karst surfaces and caves can be rapid. Speleogenesis here appears to be a hyperkarstic phenomenon.

Lo scalone d’onore dell’Università di Pavia fu realizzato nell’ambito di un piano generale di espansione e ristrutturazione del Palazzo (1819-23); l’architetto Giuseppe Marchesi – professore all’Università e autore del piano – progettò tanto l’architettura, quanto l’apparato decorativo, della cui realizzazione incaricò il maestro stuccatore ticinese Diego Marieloni. Circa venti anni fa, a seguito delle infiltrazioni d’acqua dalle coperture, alcuni stucchi della volta furono gravemente danneggiati e per proteggere gli utenti dalla caduta di materiali fu posta una rete di protezione, sulla quale negli anni si sono raccolti numerosi frammenti di stucco. Sebbene le infiltrazioni d’acqua siano state eliminate da circa cinque anni, il degrado non si è arrestato. La necessità di sostituire la rete di protezione ha motivato l’installazione di un ponteggio (ottobre 2016-marzo 2017), che ha consentito l’avvio di una campagna di studi in situ e in laboratorio volti a fornire le basi conoscitive per un futuro intervento di restauro. L'attenta osservazione dei rosoni intatti e di quelli danneggiati ha permesso di comprendere le tecniche di fabbricazione inedite; analisi mineralogiche e chimiche (diffrattometria a raggi X su polveri, microscopia ottica, FTIR) sono state condotte su frammenti caduti e su piccoli campioni prelevati dai rosoni in opera, consentendo di comprendere la peculiare composizione dello stucco e di ipotizzarne i meccanismi di degrado.

Several caves and sinkholes where snow and ice persist well into the summer exist in Nova Scotia and New Brunswick. They were often used in the past as a source of ice or for cold storage, and are known locally as “ice caves” or “ice holes”.  They are not true ice caves in the speleological sense of the term because they do not contain permanent ice, but are similar. Woodville Ice Cave in Hants County, Nova Scotia, described here, is a particularly good example.  It is in an area of unusually well-developed gypsum-anhydrite karst. Invertebrates and bats recorded from such sites are listed, and the possibility of psychrophilic fauna is suggested.

Il volume si propone di sviluppare, in un quadro sistemico e strutturato, il ruolo esercitato in Sicilia dal gesso nella storia del paesaggio e in quella del suo patrimonio di cultura materiale ed immateriale. Dagli aspetti attinenti alla cultura costruttiva a quelli della oralità, il gesso costituisce una tessera fondamentale per comprendere la cultura siciliana, al cui impiego si deve lo splendore e decoro degli apparati decorativi interni delle architetture chiesastiche.

Tanah lempung ekspansif mempunyai potensi kembang susut yang besar. Tanah ekspansif salah satu tanah bermasalah yakni rendah nya nilai daya dukung pada tanah. Salah satu upaya perbaikan tanah yang dapat dilakukan pada tanah lempung ekspansif yaitu untuk meningkatkan daya dukung tanah dengan metode perbaikan tanah atau stabilisasi secara kimiawi. Bahan stabilisasi digunakan ialah campuran tanah dengan limbah plafond gypsum. Tujuan penelitian untuk mengetahui perbandingan parameter kuat tekan bebas terhadap tanah lempung ekspansif asli dengan tanah lempung ekspansif yang distabilisasi dengan limbah plafond gypsum. Metode yang digunakan pada penelitian ini yaitu metode skala laboratorium. Data yang didapatkan dari pengujian tersebut kemudian dianalisa dengan membandingkan nilai daya dukung tanah dengan menggunakan alat kuat tekan bebas. Setelah dilakukan pengujian pada campuran variasi (15%, 20%, 25%, 30% dan 35%) dan variasi pemeraman (0 hari, 7 hari dan 14 hari) menunjukkan bahwa variasi optimum daya dukung tanah pada campuran variasi 30% sebesar 0,90 kg/cm 2 dengan variasi pemeraman 0 hari. Sedangkan pada campuran variasi 35% penunjukan penurunan pada nilai daya dukung tanah sebesar 0,89 kg/cm 2.

Kata kunci: Tanah Lempung Ekspansif, Stabilisasi Tanah, Limbah Plafond Gypsum, Kuat Tekan Bebas

MURAH BANGET!!!, Foto Plafon Gypsum Klasik, finishing plafon gypsum,  Foto2 Plafon Gypsum, Foto Plafon Gypsum Sederhana, Foto Plafon Gypsum Ruang Tamu, Variasi Plafon Gypsum, Plafon Gypsum GRC, Plafon Gypsum gyproc, Plafon GRC vs Gypsum, Harga Gypsum Magelang , Toko Gypsum Magelang, Harga Plafon Gypsum Magelang, Pasang Gypsum Magelang,  Harga Gypsum Magelang, Gypsum Magelang,  Perbedaan Plafon Gypsum dan GRC, harga Plafon Gypsum Dan GRC,  Harga Plafon Gypsum Per Meter, Harga Pasang Plafon Gypsum Per Meter, Harga Plafon Gypsum Terpasang, , Harga Lis Plafon Gypsum, Motif Plafon GypsumTerbaru, Harga Borongan Plafon Gypsum, Harga Plafon Gypsum Per m2,  Pasang Gypsum Magelang

Dwikarya Gypsum Magelang
Kami melayani pemasangan plafond gypsum, dinding partisi dengan berbagai merk bahan plafon seperti Jayaboard, Elephant, Star  , GRC, calsibord, dan lain – lain, dan dikerjakan  oleh tenaga-tenaga ahli dalam bidang pemasangan plafon maunpun dinding partisi. Untuk informasi lebih lanjut mengenai Material Gypsum serta Pemasangan Gypsum, Anda dapat menghubungi:
HEAD OFFICE : Jl. Menur Pondok Asri II, Kalijoso, Secang, Magelang
Nama   : Bpk. Waluyo
Fast Respon  : + 62 815-7855-0257
BB   : 5BBB1EA1E
Blog : dwikaryagypsum.blogspot.com

A field experiment was conducted with Boro rice (cv. Binadhan-10 and BRRIdhan 28) at Kaligonj, Satkhira to evaluate performance of two rice varieties under different nutrient management practices in a saline soil. The rice varieties, such as BRRI dhan28 and Binadhan 10 were tested under 3 levels of nutrients (T1= Recommended dose of N, P, K, S, Zn, T2 = T1 + additional Gypsum @ 125 Kg ha-1 and T3 = T1 + additional Gypsum @ 190 Kg ha-1) and the treatments were assigned in a split plot arrangement with 3 replications. The study revealed that different rice varieties and nutrient levels along with their interaction have significant effect on growth and yield of rice. Effect of varieties found highest for grain (6.38 t ha-1) and straw (6.60 t ha-1) yield in case of Binadhan-10 and considering the mean effect of different nutrient level is insignificant for both varieties. Due to interaction effect of both variety and nutrient levels, the maximum grain yield was found as 6.61 t ha-1 under the treatment combination V2T2 i.e. Binadhan-10 along with recommended dose of N, P, K, S and Zn with 125 kg gypsum ha-1. Between these two varieties Binadhan-10 showed better performance compared to BRRI dhan28 at saline condition.

This paper discusses the analysis of an altar frontal on plaster dated to A.D. 1681. The altar frontal is located in the Sanctuary of the Virgin Mary in Neive (CN) and it might be the most ancient altar frontal known in Piedmont.
The materials, techniques and cultural background of the altar frontal are analyzed, in order to deeply understand its conservation status and provenance. Moreover, a detailed artistic comparison with two later altar frontals situated in Tigliole (AT) is provided, in order to try to identify the author, who is thought to be the famous artist Giovanni Massa.
The paper is in Italian. How to reference: Laura Dellapiana, La riscoperta di un paliotto in scagliola del 1681, in  “Alba Pompeia”, Nuova serie – Anno XXXIV – Fascicolo II – II Semestre 2013, pp. 73-84

A new genetic facies model for deep-water clastic evaporites is presented, based on work carried out on the Messinian Gessoso-solfifera Formation of the northern Apennines during the last 15 years. This model is derived from the most recent siliciclastic turbidite models and describes the down current transformations of a parent flow mainly composed of gypsum clasts. The model allows clearer comprehension of processes controlling the production and deposition of clastic evaporites, representing the most common evaporite facies of the northern Apennines, and the definition of the genetic and stratigraphic relationship with primary shallow-water evaporites formed and
preserved in marginal settings. Due to the severe recrystallization processes usually affecting these deposits, petrographic and geochemical analyses are needed for a more accurate interpretation of the large spectrum of recognized
gravity-driven deposits ranging from debrisflow to low-density turbidites.
Almost all the laminar ‘balatino’ gypsum, previously considered a deep-water primary deposit, is here reinterpreted as the fine-grained product of high to low-density gravity flows. Facies associations permit the framing of the distribution of clastic evaporites into the complex tectonically controlled depositional settings of the Apennine foredeep basin. The Messinian Salinity
Crisis occurred during an intense phase of geodynamic reorganization of the Mediterranean area that also produced the fragmentation of the former Miocene Apennine foredeep basin. In this area, primary shallow-water evaporites equivalent to the Mediterranean Lower Evaporites, apparently only formed in semi-closed thrust-top basins like the Vena del Gesso Basin.
The subsequent uplift and subaerial exposure of such basins ended the evaporite precipitation and promoted a widespread phase of collapse leading to the resedimentation of the evaporites into deeper basins. Vertical facies sequences of clastic evaporites can be interpreted in terms of the complex
interplay between the Messinian tectonic evolution of the Apennine thrust belt and related exhumation–erosional processes. The facies model here proposed could be helpful also for better comprehension of other different depositional
and geodynamic contexts; the importance of clastic evaporites deposits has been overlooked in the study of other Mediterranean areas. Based on the Apennine basins experience, it is suggested here that evaporites diffused into
the deeper portions of the Mediterranean basin may consist mainly of deepwater resedimented deposits rather than shallow-water to supratidal primary evaporites indicative of a complete basin desiccation.

MURAH BANGET!!!, Plafon Gypsum Drop Ceiling, Plafon Gypsum, Plafon Gypsum Ruang Tamu Minimalis, Model Plafon Gypsum Elegan, Motif Plafon Gypsum, Kumpulan Model Gypsum Minimalis, Model Plafon Gypsum Kamar Tidur, Model Plafon Gypsum, Motif Plafon Gypsum, Harga Borongan Pasang Plafon Gysum, Toko Gypsum Magelang, Harga Plafon Gypsum Magelang, Pasang Gypsum Magelang,  Harga Gypsum Magelang, Gypsum Magelang,  Plafon GRC, plafon gypsum ruang tamu, plafon gypsum kamar tidur, plafon gypsum sederhana, plafon gypsum teras, plafon gypsum kamar minimalis, plafon gypsum unik, plafon gypsum adalah, plafon gypsum vs triplek, plafon gypsum akustik, plafon gypsum atau grc, plafon gypsum atau pvc, plafon gypsum a plus, plafon gypsum tahan air, plafon gypsum tali air.

Dwikarya Gypsum Magelang
Kami melayani pemasangan plafond gypsum, dinding partisi dengan berbagai merk bahan plafon seperti Jayaboard, Elephant, Star  , GRC, calsibord, dan lain – lain, dan dikerjakan  oleh tenaga-tenaga ahli dalam bidang pemasangan plafon maunpun dinding partisi. Untuk informasi lebih lanjut mengenai Material Gypsum serta Pemasangan Gypsum, Anda dapat menghubungi:
HEAD OFFICE : Jl. Menur Pondok Asri II, Kalijoso, Secang, Magelang
Nama   : Bpk. Waluyo
Fast Respon  : + 62 815-7855-0257
BB   : 5BBB1EA1E
Blog : dwikaryagypsum.blogspot.co.id





Toko Plafon Gypsum Magelang, Harga Plafon Gypsum Magelang, Pasang  Plafon Gypsum Magelang,  Harga  Plafon Gypsum Magelang, Harga Plafon Gypsum Per Meter Magelang, Harga Pasang Plafon Gypsum Per Meter Magelang, Harga Lis Plafon Gypsum Magelang, Harga Borongan Plafon Gypsum Magelang, Tukang Gypsum Magelang

MURAH BANGET!!!, Plafon Gypsum Murah, Pemasangan Plafon Gypssum Murah, Harga Plafon Gypsum Murah, Jasa Pasang Plafon Gypsum Murah, Pasang Plafon Gypsum Murah, Harga Pasang Plafon Gypsum Murah, Plafon Gypsum, Merk Plafon Gypsum Yang Bagus, Gypsum Akustik, Toko Gypsum Magelang, Harga Plafon Gypsum Magelang, Pasang Gypsum Magelang,  Harga Gypsum Magelang, Gypsum Magelang,  Plafon Gypsum Drop Ceiling, Plafon Gypsum, Plafon Gypsum Ruang Tamu Minimalis, Model Plafon Gypsum Elegan, Motif Plafon Gypsum, Kumpulan Model Gypsum Minimalis, Model Plafon Gypsum Kamar Tidur, Model Plafon Gypsum, Motif Plafon Gypsum, Harga Borongan Pasang Plafon Gysum.


Dwikarya Gypsum Magelang
Kami melayani pemasangan plafond gypsum, dinding partisi dengan berbagai merk bahan plafon seperti Jayaboard, Elephant, Star  , GRC, calsibord, dan lain – lain, dan dikerjakan  oleh tenaga-tenaga ahli dalam bidang pemasangan plafon maunpun dinding partisi. Untuk informasi lebih lanjut mengenai Material Gypsum serta Pemasangan Gypsum, Anda dapat menghubungi:
HEAD OFFICE : Jl. Menur Pondok Asri II, Kalijoso, Secang, Magelang
Nama   : Bpk. Waluyo
Fast Respon  : + 62 815-7855-0257
BB   : 5BBB1EA1E
Blog : dwikaryagypsum.blogspot.com





Toko Plafon Gypsum Magelang, Harga Plafon Gypsum Magelang, Pasang  Plafon Gypsum Magelang,  Harga  Plafon Gypsum Magelang, Harga Plafon Gypsum Per Meter Magelang, Harga Pasang Plafon Gypsum Per Meter

Gypsum dissolves relatively quickly and gypsum karst can evolve on a rapid time scale that may be accelerated by human induced change, often resulting in severe subsidence damage. The area close to Inandık stream in Central Anato-lia, Turkey, is affected by subsidence in two ways: formation of collapse sinkholes on agricultural land and progressive subsidence in Inandık village that has damaged buildings. This study focuses on these subsidence phenomena. Seven large sinkholes were formed on a terrace where episodic incision of the fluvial system has led to reduced thickness and mechanical strength of the cavity roof; a process that also increases the hydraulic gradient and enhances cavity development in the terrace area. These processes formed a sinkhole-prone terrace surface. The other subsidence phenomena, which have increased progressively in the last decade, relate to human activity in Inandık village. Water consumption increased after domestic water service systems were installed in houses in 2007, and in 2012 a sewer system was built in the village. Due to cracks and breakage, leaking water from buildings and sewer pipes infiltrated the gypsum substratum, resulting in dissolution of the bedrock and superficial cavity formation, as shown by GPR and borehole data. The process leading to subsidence caused severe damage to buildings. Consequently, it was decided to relocate the village three km south of its current location because of the high level of damage.

L’Emilia-Romagna è tra le poche regioni dell’Italia settentrionale ad ospitare cospicui affioramenti gessosi, sia triassici nell’alto Appennino, sia messiniani nel basso Appennino. Accanto al loro valore ambientale, questi depositi sono caratterizzati da una rilevante dimensione culturale, frutto di millenni di condizionamenti e interazione tra comunità locali e substrato evaporitico. Il saggio propone una sintesi su scala regionale dei termini più significativi di tale intersezione, da temi “materiali” come l’utilizzo umano delle cavità naturali o l’attività estrattiva tra passato e presente, a temi “immateriali”, come ad esempio le rappresentazioni folkloriche e letterarie legate ai paesaggi carsici gessosi. Dal punto di vista cronologico, il contributo si focalizza sull’età moderna e sull’età contemporanea, dedicando solo rapidi cenni ai periodi precedenti.

Ameliorating the saline-sodic soil process represents an important target in the agricultural security program of Egypt. In this concern, a field trial was conducted for improving a salt-affected clay soil provided with a tile drainage system at Mehallet Mousa, Kafr El-Shiekh Governorate, Egypt. The main target of this work was at identifying the effective role of applied gypsum, as a soil chemical amendment, with different rates on physico-chemical and hydrological properties of such soil as well as maximizing its productivity from maize and wheat crops. The applied gypsum treatments were categorized into: i. control without applied gypsum, ii. 3.75 ton gypsum/fed ≈ 75 % of gypsum requirements (GR) for the uppermost 15 cm, iii. 5 ton gypsum/fed ≈ 100 % GR and iv. 6.25 ton gypsum/fed ≈ 125 % GR. The applied gypsum rates were uniformly spread on surface and thoroughly mixed with the soil top 15 cm, and then followed by a recycle of wetting and drying was repeated four times through a period of about two months.. A recycle of wetting and drying was repeated four times through a period of about two months. Soil samples at depths of 0-15, 15-30, 30-45 and 45-60 cm were periodically collected after 3, 6, 9 and 12 months from starting the experiment to determine soil physico-chemical, i.e., ECe, ESP, salt leaching index, bulk density, infiltration rate, aggregation index and quickly drainable pores. Moreover, the shape of water table between drains, water table depth were monitored as well as the drainage intensity factor "a" and the rate of water drawdown were calculated.
The obtained results revealed that the reduction percentages of soil salinity after 3, 6, 9 and 12 months from starting the experiment reached 30.3, 33.1, 35.4 and 45.0 % for the applied gypsum rates 75 % GR vs 34.6, 36.9, 45.6 and 53.3 % for 100 % GR and 35.0, 66.6, 69.9 and 75.7 % for 125 % GR, respectively. That was true, since additional gypsum in excess of the requirement helped speedily soil amelioration process. In general, the soil salinity reached the safe limits of soil salinity (ECe=< 4.0 dS/m) and sodicity (ESP= < 15 %) after 6 months of applying 100 and 125 % GR. Also, the values of ECe and ESP were tended to a gradual decrease with increasing the experimental time, but the reverse was true for the values of salt leaching index that showed gradual increases.
Concerning soil physical soil properties, the obtained results showed a pronounced increase in infiltration rate, where the increase percentages ranged 42.3-56.0, 43.7-60.9 and 55.4-91.5 % at 75, 100 and 125 % GR, respectively. A similar and parallel trend was also observed for the values of quickly drainable pores. Such favourable effect refers to the released Ca2+ from gypsum that leading to improve soil structure, creation of friable granules and conductive pores that enhancing water penetration, and then promote a sufficient cycle of wetting and drying. Also, a parallel increase was achieved for the aggregation index values as time elapsed and increasing gypsum rates, where the corresponding relative increase percentages ranged between 18.0-89.3, 55.0-120.0 and 108.0-140.3 % at 75, 100 and 125 % GR, respectively. Moreover, a noticeable decrease was observed for soil bulk density due to adding gypsum as an amendment comparing with the control treatment.
Regarding soil hydrological properties, it was clearly showed a marked drop in water table level differs from one day to another as well as the applied gypsum rates, probably due to the nature of the stratified layering of such Nile alluvial soil. The average rate of water table drawdown after one year of gypsum application mounted 35.2, 44.8 and 95.0 % for soils treated with 75 %, 100 % and 125 % GR as compared with the initial state, respectively. In general, lowering the water table has given the top soil a chance to dry, shrink and creating water passageways. It was also noticed that the drainage intensity factor (a) tended to increase with increasing the applied gypsum rate, where its greatest value was achieved at 125 % GR, may be due to the increase of released Ca2+ and its positive action to link clay particles, and in turn enhance soil internal drainage and water movement to drains. In addition, a parallel pronounced decrease in the total water resistance was associated with increasing the applied gypsum rate, i.e., 7.69, 23.07 and 30.77 % at 75, 100 and 125 % GR, respectively. This means that applied gypsum led to improve the soil structure which helped in creating a more permeable soil medium with less resistance to water flow towards tile drains.
The achieved amelioration in physico-chemical and hydrological properties of the studied soil positively reflected on the increases of grain yields of both summer maize and winter wheat, which were approached 27.8, 50.0 and 61.1 % for maize vs 25.7, 42.9 and 57.1 % over the control for wheat at 75, 100 and 125 % GR, respectively. Finally, the obtained results suggest that this work is considered as scientific and logic fundamental base for a successful agricultural development of such salt affected area as well as possible to increase unite area income.

Recently, Dutta and Yadav (2021) reported on the effects of gypsum treatment — considering gypsum content (defined as the gypsum-to-soil dry mass ratio with G = 0, 2, 4, 6, 8, and 10%) and curing period (with CP = 0, 1, 7, and 28 days) — on the consistency limits, compactability, and unconfined compressive strength (UCS) of a calcium bentonite soil. In the present discussion article, some apparent shortcomings and limitations associated with the regression models proposed by Dutta and Yadav (2021), as well as some noted inconsistencies in their experimental results and data interpretations, are scrutinized. As a way forward, new and improved multivariable regression models are introduced (and validated) by the authors of the present article to complement the original experimental results reported by Dutta and Yadav (2021).

Amboy Crater is in T.05-06N, R.10-1E, SBM. It is northwest of Bristol (Dry) Lake, northeast of the Lead Mountains (Northern Bullion Range), southeast of the Lava Hills, and southwest of the Bristol Mountains.

The Amboy gypsum mine is on the east side of Amboy Crater lava flows and west of the Bristol Lake Salt Plant.

Amboy Deposits. Location: secs. 3, 4, 8, 10, 11, 17, 19, 20, 29, 30, T. 5 N., R . 12 E . , S.B.M., along the northwest side of Bristol Lake and extending about 5 miles south and 3 miles southeast of Amboy (Wright and others, 1953., p. 228).

OWNERSHIP

Ownership: U . S . Gypsum Company, Chicago, Illinois, owns 23 patented placer claims covering 1,822 acres (Wright and others, 1953., p. 228).

GEOLOGY

A regional geologic mosaic of the Bristol and Old Dad Mountains is available at:

https://www.academia.edu/s/bd8414fe42/geologic-mosaic-of-the-bristol-and-old-dad-mountains-san-bernardino-county-california-text

A regional stratigraphic compilation for this mosaic is at:

https://www.academia.edu/31570340/Stratigraphic_Compilation_for_the_Bristol_and_Old_Dad_Mountains_San_Bernardino_County_California_TEXT

My report on the geology of the Amboy Crater Area can be accessed at:

https://www.academia.edu/52331735/Amboy_Crater_Area_Mines_San_Bernardino_County_California

or

https://www.academia.edu/52331735/Amboy_Crater_Area_Mines_San_Bernardino_County_California

Bishop (1963) mapped the Amboy Crater Area as containing outcrops of:


Ql: Quaternary lake deposits
Qpvb: Pleistocene basalt
Quaternary and/or Pliocene cinder cones

Bishop (1963) mapped the area of the Amboy Crater Area as a cinder cone within Pleistocene pyroclastic basalt (Qpvb).

Bishop (1963) mapped the area of the Amboy Gypsum mines as being in Quaternary Lake sediments (Ql):

Kupfer and Basset (1962) mapped the following units in the Amboy Crater Area:
Qa: Alluvium

Playa Deposit
Qca
Qx
Qxb
Qxc
Qxg
Qoa: Quaternary Older Alluvium
Qb2: Quaternary basalt flows and cones

Kupfer and Bassett, 1962, mapped the area of the Amboy Crater Mines as
Quaternary basalt flows and cones (Qb2).

Kupfer and Bassett (1962) mapped the area of the Amboy Gypsum Mine as in gypsum-rich lake sediments (Qxg):
Bedford and others (2010) and Phelps and others (2012) mapped the Amboy 100K Quadrangle. In the Amboy Crater Area they identified the following units:

Substrate Units: Qmv: Quaternary Mafic Volcanics

Hill Slope Deposits

Qha/Qmv

Alluvial Units
Qya

Wash Deposits
Qyw-Qaw: Young Wash-Active Wash deposits

Pediment Surfaces
Qpd-fpg: Deeply dissected pediment, felsic plutonic rocks converting to gruss
Qpi/pc: Incised pediment, partly consolidated

Eolian Units
Qye/Qmv: Young eolian sand/Quaternary mafic volcanics
Qae/Qmv: Active eolian sand deposit/Quaternary mafic volcnics


Qyp: Younger playa deposit

Bedford and others (2010) mapped the area of the Amboy Crater Area as Active eolian sand deposit/Quaternary mafic volcanics (Qae/Qmv) and Hillslope/Quaternary mafic volcanic rocks (Qha/Qmv).

Bedford and others (2010) mapped the Amboy gypsum mines as being in young Quaternary playa deposits (Qyp):
Dibblee and Minch (2008f) mapped the area of the Amboy Crater Area as having the following exposures:

Qa: Alluvium
Qoa: Older Alluvium
Qb: Pleistocene basalt

Dibblee and Minch (2008f) mapped the area of the Amboy Crater Area as Quaternary basalt (Qb).

The Amboy Gypsum Mine is to the east of Dibblee and Minch’s (2008f) map.


Schafer and others (1959) mapped the following units in T.5N, R.11 and 12E, SBM:

Qal: Alluvium
Qabf: Recent basalt flows
Qabcc: Younger cinder cones

Playa Sediments of Bristol Lake

Qblgs: Clay
Qblg: Gypsum and Clay
Qblc: Clay and Silt
Qblh: Clay and Halite

Schafer and others mapped the Amboy Gypsum mines as being in gypsum-rich Bristol Lake sediments (Qblgc).

A belt of gypsum extends around the north and west sides of Bristol Dry Lake and is distinguished on the geologic map. It consists of a mesh of selenite crystals and finer spongy gypsum intermixed with clay and silt. Salt in varying small amounts is commonly present. Major recovery of gypsum was made between 1906 and 1924 by the Consolidated Pacific Cement Plaster Co. who worked in Secs. 3 and 10, T.5N., R.12E. The depth or mining was limited by the water table which was at 6-8 feet. The recovery of the gypsum is best described by Fletcher and Melhase (1920, p. 20-21) and other details are given by Ver Planck (1952, p. 47). See also Gale (1951, p. 5-6) and Wright, et al. (1953, p. 228)(Schafer and others, 1958, p. 5).

U. S. Gypsum Company. The original workings in Secs. 3 and 10 and also Secs. 19 and 10 T.5N., R.12E. are owned by this company (Ver Planck, 1952, p. 47), but there were no present operations )(Schafer and others, 1958, p. 5).

Mining and Claims in Sections. 8 and 17, T.5N., R.12E. Prospecting and intermittent operations are carried on by a group in this area. In the S½ Section 8 a bed about 6 feet thick containing up to 60 percent fine-grained cellular masses of gypsum was observed in brown playa clay covered at the surface with white saline crust )(Schafer and others, 1958, p. 5-6).

With the exception of the Shire deposits, all of the known gypsum occurrences that have been prospected or mined in the county occur in Tertiary or Quaternary formations and are interbedded with shale and siltstone. The Shire deposits are part of the Permian Kaibab formation. Gypsum concentrations range from beds an inch or less thick, in rock composed mostly of shale or siltstone, to layered units as much as 150 feet thick, of which the clay or siltstone fraction is very small. Development has been hindered by the remoteness of the large deposits from rail transportation (Wright and others, 1953, p. 228).

The gypsum occurs in a belt a mile or less wide along the northwest margin of Bristol Dry Lake.  In general, the gypsum appears most abundant near the front of a basaltic lava flow extending eastward from the Amboy crater. The material was removed from shallow excavation. 6 to 8 feet in maximum depth. The gypsum beds may be even thicker but deeper excavation was prevented by a shallow water table. The gypsum occurs as a mush of selenite crystals mixed with various proportions of salty mud. This material was carried to a plaster mill, about 2 mile southeast of Amboy, where most of the salt and mud was removed and the gypsum was calcined and prepared for shipment transportation (Wright and others, 1953, p. 228).

DEVELOPMENT

Although gypsum deposits of possible commercial interest exist at several localities in San Bernardino County, only the Amboy deposits at Bristol Lake have been seriously worked. Since this operation was shut down in 1924, there has been no recorded production of gypsum in the county. Of the unexploited gypsum occurrences, probably those with the largest reserves are the Avawatz deposits, along the north base of the Avawatz Range, the Shire deposits northeast o f Clark Mountain, and deposits at Danby Dry Lake (Wright and others, 1953, p. 228).

Mammoth Cave (Kentucky, USA) is the world's longest human-navigable cave system. Gypsum (CaSO4∙2H2O) crystals line many dry passages of the limestone cave and the source of sulfur for the gypsum remains uncertain. Previous workers have suggested sulfate from pyrite oxidation, Mississippian-aged sulfate evaporites, and Pleistocene soil sulfate as possible sulfur sources. We use sulfur isotopes (δ34S) to constrain the gypsum sulfur source by comparing the δ34S values of different possible sources to that of gypsum throughout the cave. δ34Sgypsum values (n = 106) from 12 different locations within the Mammoth Cave system are along a continuum of δ34S values from –12.0‰ to +12.8‰, with little variability along the crystal growth axis or between samples within the same cave chamber. Neither sulfur from coeval sedimentary evaporites (i.e., gypsum, anhydrite) nor from formations overlying the cave is required to explain the δ34Sgypsum data. Rather, the range of pyrite δ34S in strata immediately surrounding the cave is sufficient to generate the spectrum of observed δ34Sgypsum. Modern water δ34SSO4 values are similar to the host formation δ34Spyrite, suggesting that oxidized pyrite from the host formation continues to be a major sulfur source to this day. Together, these observations strongly suggest a significant local source of sulfur for Mammoth Cave gypsum, the majority (66%–100%) of which is derived from the oxidation of pyrite in strata adjacent to the cave.