GYPSUM PROPERTIES, PRODUCTION AND APPLICATIONS

In Gypsum Properties Production and Applications ISBN 978-1-61728-308-6

Editor Delia H Sampson copy 2011 Nova Science Publishers Inc

Chapter 9

GYPSUM PROPERTIES PRODUCTION

AND APPLICATIONS

Habes A Ghrefata and Fares M Howari

a King Saud University Department of Geology and Geophysics PO

Box 2455 Riyadh 11451 Saudi Arabia b Environmental Science Program College of Arts and Science The University

of Texas of the Permian Basin 4901 East University Odessa TX 79762 USA

ABSTRACT

Gypsum is the most common sulfate mineral on earth and is commonly associated

with halite anhydrite sulfur calcite and dolomite in recent coastal (sabkha or salina)

andor continental (playa) evaporite deposits Gypsum can appear as transparent crystals

(selenite) fibrous elongated crystals (stain spar) granular and compact masses

(alabaster) and in rosette-shaped aggregates called desert roses The calcium sulfate-

water system occurs as three principal solid phases gypsum (CaSO42H2O) bassanite

(CaSO405H2O) and anhydrite (CaSO4) Only gypsum and anhydrite are stable phases of

these three phases Uncalcined gypsum and calcined gypsum are consumed in large

quantities worldwide principally for use in the construction and agricultural industries In

building it is used in plaster plaster of Paris wallboard cement and ceramic tiles In

agriculture it is used as an amendment to neutralize sodic soils and to promote the

growth of vegetables World resources of gypsum are large and widely distributed The

top producing countries of gypsum in 2009 in descending order are China Iran Spain

United States Thailand Japan and Canada In 2009 crude and uncalined gypsum

production in United States were estimated to be 94 and 77 million tons respectively

The average values per metric ton reported by US producers in 2009 were $85 for crude

gypsum and $400 for calcined gypsum Demand for gypsum products is expected to

decreases in the coming decade as housing starts continue to drop

Corresponding author E-mail habesksuedusa Phone 0096614676233 Fax 00966-1-4676214

Habes A Ghrefat and Fares M Howari 192

1 INTRODUCTION

Gypsum was derived from the Greek word gypsos which means plaster Originally it

referred to the form of gypsum which has been heated to a high temperature to drive off the

water in its crystal structure this is called calcined gypsum or Plaster of Paris Gypsum was

used in Egypt over 4000 years ago and was a traditional building material in Mediterranean

and Middle East countries It was introduced into Europe in the 13th

century as a wall plaster

Gypsum is one of the most widely used minerals in the world and of large commercial value

(Kyle 1992) Gypsum (CaSO4middot2H2O) differs from other calcium sulfate minerals such as

bassanite (CaSO4middot05H2O) and anhydrite (CaSO4) by the number of water molecules in its

crystalline structure Gypsum and Anhydrite are products of partial or total evaporation of

inland seas and lakes Both of these minerals occur in nature in a variety of forms Gypsum is

most commonly found in layered sedimentary deposits in association with halite anhydrite

sulfur calcite and dolomite This chapter will focus on physical and chemical properties of

gypsum world production of gypsum and prices and demand of gypsum as well Moreover

this chapter also focuses on several gypsum applications in industry and agriculture

2 PROPERTIES OF GYPSUM

Gypsum is very soft at 2 on hardness scale of Moho (Deer et al 1992) Gypsum is so

soft that a fingernail can easily scratch it It is characterized by a monoclinic crystal system

and a perfect cleave The specific gravity of gypsum is 23 It has a white streak and a

vitreous luster

Three principal solid phases in the calcium sulfate-water system occur gypsum

(CaSO42H2O) bassanite (CaSO405H2O) and anhydrite (CaSO4) (Deer et al 1992) Only

gypsum and anhydrite are stable phases of these three phases Anhydrite is only dominant in

water with a temperature greater than 44 C on Earth at standard pressure and neutral pH

(Holland and Malinin 1979 Deer et al 1992)

Dry solid gypsum is a stable up to temperatures of 70 C at standard pressure at which

point bassanite is created Anhydrite is formed at temperature above 200 C (Holland and

Malinin 1979 Deer et al 1992) Gypsum is not stable under burial of more than a few

hundred meters at which point anhydrite is generated (Schreiber and El Tabakh 2000)

Gypsum is also converted to anhydrite when solid gypsum exposed to saline solutions (Deer

et al 1992)

According to Cloutis et al (2007) gypsum has been shown to be stable at Martian

surface pressures for periods of a few months bases on the on the spectral analysis

Gypsum has several variety names that are widely used in the mineral trade (1) Selenite

Selenite occurs as flattened and often twinned gypsum crystals (gt2 mm) Selenite crystals are

most often transparent and colorless (Figure 1) These crystals deposit below the water table

in a continuously subaqueous environment (Warren 1982) and show a pearl like luster (2)

Satin spar Satin spar occurs as compact fibrous elongated crystals (Figure 1) It shows a silky

luster and can exhibit some coloration (3) Alabaster A very fine grained massive white or

lightly-tinted variety of gypsum is called alabaster (Figure 1) Alabaster is an ornamental

stone used in fine carvings for centuries even eons and (4) Desert rose In arid areas gypsum

Gypsum Properties Production and Applications 193

can occur in a flower-like form typically opaque with embedded sand grains called desert rose

(Figure 1)

Gypsum is commonly associated with shallow and deep marine precipitate deposits as

well as coastal (sabkha or salina) and continental (playa) evaporite deposits (Warren 1982

Schreiber and El Tabakh 2000) Typical seawater contains approximately 015 dissolved

CaSO4 which equals about 17 cm precipitated gypsum per 100 m of evaporated seawater

(Holland and Malinin 1979 Deer et al 1992) Gypsum is generally the second mineral to

precipitate from evaporating seawater after calcite (Holland and Malinin 1979 Spencer

2000) In shallow marine environments gypsum is commonly deposited as crusts and

clusters while in deep marine environments gypsum is most often deposited as alabaster

gypsum (Schreiber and El Tabakh 2000)

Table 1 World production of gypsum (Thousand metric tons)12

(httpmineralsusgsgovminerals)

Country 2006 2007e 2008 2009e

United States8 19000 r 17900 3 14400 9400

Algeria 1200 r 1200 3 1700 1700

Australia 4200 r 4200 4000 4000

Austriae4 1000 1000 1000 1000

Brazil4 1700 rp 1800 2100 2100

Canada4 9000 r 7700 3 5800 5500

Chinae 35000 r 37000 46000 42000

Egypte4 2000 2000 2000 2000

Francee4 4800 4800 4800 4800

Germany4 1800 r 1800 1900 1900

Indiae 2500 2500 2600 2600

Iran6 12000 re 12000 12000 12000

Japan 5800 r 5900 5800 5800

Mexico4 6100 r 6100 5100 4500

Poland4 1400 r 1600 3 1600 1300

Russiae 2200 2300 2300 2300

Spain4 11500 rp 11500 11500 11500

Thailand 8400 r 8600 3 8000 8000

United Kingdom4 1700 r 1700 1700 1700

Other countries 17700 21400 24700 27900

World total (rounded) 149000 153000 159000 152000 EEstimated

PPreliminary

RRevised

1World totals US data and estimated data are rounded to no more than three significant digits may

not add to totals shown 2Table includes data available through July 15 2008

3Reported figure

4Includes anhydrite

5Less than 05 unit

6Data are for years beginning March 21 of that stated

8Excludes byproduct gypsum

Desert rose Satin spar

Selenite Alabaster

Figure 1 Pictures of Desert rose Satin Spar Selenite and Alabaster These pictures were obtained

from httpgwydirdemoncoukjomineralsgypsumhtm

In salinas and playas gypsum occurs as (1) gypsite a fine grained (lt60 mm) gypsum

crust dissolved and redeposited by rain (2) gypsarenite sand-sized (60 mm-1 mm) gypsum

crystals deposited in unstable or periodic salinity environments and (3) selenite Gypsum is

also presented as a continental evaporite when it is dissolved in and transported by

percolating groundwater which is pulled to the surface by capillary action depositing

gypsarenite selenite and anhydrite crystals as the water evaporates (Deer et al 1992

Langford 2003)

04 06 08 1 12 14 16 18 2 22 24

Wavelength (Micrometer)

Figure 2 The USGS library VNIR-SWIR spectra (Clark et al 1993) of gypsum

Sulfuric acid solutions moving through Ca-rich rocks may result in gypsum and anhydrite

formation Acidic waters are often either created by volcanic gases interacting with meteoric

water or by weathering of sulfides (Holland and Malinin 1979 Deer et al 1992) Gypsum

and anhydrite rich mineral assemblages are often produced by the action of sulfurous volcanic

vapors on Ca-rich rocks (Golden et al 2005) Gypsum can also be produced by sulfurous fog

acting on Ca-rich materials (Eckardt and Schemenauer 1998 Golden et al 2005)

The solubility of gypsum in water depends on the chemical composition of the aqueous

solution the temperature and pressure Gypsum and halite solubilities in water at 25C and 1

atmosphere pressure are 24 gL and 360 gL respectively (Ford and Williams 1989) In

distilled water at 20C gypsum and halite are respectively 183 and 25000 times more soluble

than calcite (Jackus 1977) Temperature experiments show that at one atmosphere pressure

gypsum has its maximum solubility between 35C and 40

C (Hardie 1967 Blount and

Dickson 1973 Sonnenfeld 1984 White 1988) Gypsum becomes less soluble at higher

temperatures as opposed to other salts Because gypsum dissolves over time in water gypsum

is rarely found in the form of sand However the unique conditions of the White Sands

National Monument New Mexico USA have created a 710 kmsup2 expanse of white gypsum

sand enough to supply the construction industry with drywall for 1000 years

Gypsum solubility is also affected by the type and concentration of the dissolved ions in

the aqueous solution and saline and common ions (Sonnenfeld 1984) The saline effect

produces an increase in the solubility of gypsum by the high ionic concentration ionic

strength of the solution This causes a decrease in the activity of the SO2 and Ca2+

ions The

solubility of gypsum in saline solutions and in brines is strongly dependent on NaCl

concentration (Ponsjack 1940 Schreiber and Schreiber 1977) Ponsjack (1940) showed that

NaCl concentrations of between 75 and 200 gL increase the solubility of gypsum by 3 to 4

times over that in pure water However if the dissolved ions in water include Ca2+

and SO4 -2

the common ion effect occurs and the solubility of gypsum decreases

Gypsum is a frequent but minor component in the soils of humidndashtemperate regions

where it is continuously leached and is considered transient In these regions gypsum only

occurs in significant quantities where the parent material of soil formation is derived from

evaporates and some other geological material of marine origin In arid and semi-arid

climates gypsum in soils or other surficial materials is more permanent (Drake 1997

Schuumltt 1998) If a sufficient amount of gypsum occurs in the soils may be classified as

gypsiferous Anhydrite forms rarely at the surface but only in arid and hot supratidal

environments (sabkha) in the presence of concentrated brines (Butler 1969 Shearman 1985)

Gypsum is found in nature most commonly as the sparingly soluble salt CaSO42H2O

(Nettlejohn et al 1982 Verhaye and Boyadgiev 1997) The concentration of a saturated

solution of gypsum is about 15 mM and so is more soluble than calcite which typically gives

in soil solution a concentration of between 1 and 10 mM Ca2+

depending on pH and partial

pressure of CO2 (Stumm and Morgan 1970)

United States Geological Survey (USGS) library spectrum of gypsum is shown in Figure

2 The spectrum of gypsum shows major absorption features in VNIR and SWIR regions due

to overtones and combination tones of molecular water (Hunt et al 1971a) The intensity of

the absorption features will decrease and their shapes will change when gypsum is mixed with

other salts and substrate minerals (Lindberg and Smith 1973) The absorption minimum

around 12 microm is due to a combination of the H-O-H bending fundamental and the first

overtones of the O-H stretch The absorption features between 14 and 16 microm are due to the

first overtone of the O-H stretching fundamental The absorption bands near 174 microm are due

to combinations involving the fundamental H-O-H bend the fundamental O-H stretch and

low frequency vibration modes of the structural water molecules The strong absorption

features near 19 microm are due to a combination of the O-H stretching and the H-O-H bending

fundamentals The absorption bands around 22 microm are attributed to a combination of the

fundamental O-H stretch and the first overtone of the water Gypsum and anhydrite showed

similar spectral behavior in the 5ndash25 μm range (Lane and Christensen 1998) The results of

Lane and Christensen (1998) also showed that emission features above 7 μm can undergo

dramatic changes as grain size is reduced below 100 μm

3 GYPSUM APPLICATIONS

Gypsum is consumed in large quantities worldwide principally for use in the

construction industries Also some of gypsum is used in agricultural applications More

information about gypsum uses in agriculture and industry is available at

httpwwwusagypsumcom

31 Gypsum Industrial Uses

Gypsum is used in building because it has fire-resisting quality and heat insulation and is

considered as a good sound absorbing material Moreover gypsum is easily converted in a

cementitious material and is quick setting and eliminates the need for formwork Gypsum is

used in a wide variety of industrial applications including

1 Portland cement

Gypsum is a component used in Portland cement It slows the hardening of cement

because of its physical makeup This allows the cement to be used much more easily than if it

hardened at its regular speed

2 Specialty concrete products

Specialty concrete contains specialized binders such as K silicate calcium aluminate

sulfur and oxysulfate or polymer resins In contrast to conventional construction products

specialty concrete is not based on Portland cement Instead specialty concrete is composed of

specialty cement such as potassium silicate that is mixed with water a coarse aggregate such

as gravel or crushed stone and a fine aggregate or sand

3 Plaster molds

Natural gypsum of high purity is used to produce special plasters for example for use as

plaster moulds in the pottery industry Gypsum plaster is a building material generated by

heating gypsum to 150 C The mixture is ground gypsum mixed with water and heated then

released as steam The mixture then cools and reforms as gypsum The use of plaster of Paris

as molds for casting concrete for building structures has wide applications

4 Filler in paint

Gypsum can be added to paint as a filler

5 Glass manufacturing

Small amounts of very pure gypsum are used in a wide range of industrial applications

including glass making

6 Chemical food and polymer additives

High quality calcium sulfate additives produced from high purity gypsum is used in a

wide range of industrial and chemical applications such as specialty cements used for grouts

and flooring High purity gypsum is also used to manufacture food and pharmaceutical

additives and polymer additives including thermoplastics thermosets and coatings

7 High strength floor underlayments

In new commercial construction gypsum concrete underlayments are applied over

structural concrete or precast concrete planks to create a smooth monolithic floor surface that

delivers superior strength sound control and fire resistance

8 Industrial plasters and gypsum cements for art and casting

Industrial plasters and gypsum cements readily blend with chemicals and aggregates to

achieve special properties Both wet and dry blending are performed with various chemicals

powders and granular materials such as talk and iron oxide Industrial plasters and gypsum

cements are noncombustible These materials provide a high degree of fire resistance and are

safe to handle and work with Some of these materials are nontoxic nonallergenic

odorless and nonirritating to the skin

9 Road and surface repair patching materials

Road repair products are designed to achieve high early strength These products offer the

advantage of allowing road repairs to busy thoroughfares to be accomplished within hours

thereby minimizing disruption of traffic Theses products include above grade repairs such as

bridge decks ramps parking lot decks and on grade road repairs These products are

available for different weather conditions

10 Thermoplastics thermosets and coatings

Calcium sulfate additives are extremely white non-abrasive resistant to mild acids and

safe to use These additives are used in a wide range of polymer applications such as

thermoplastics thermosets and coatings

11 Erosion and dust control products

Gypsum can be used to decrease wind and water erosion of soil Water infiltration rates

into soils as well as the hydraulic conductivity of the soil can be improved using gypsum

Severe dust problems can be decreased especially when combined with use of water-soluble

polymers

12 Hydro seeding

Hydro seeding is a method of applying seed directly to the soil surface using water as the

prime carrier to create a temporary micro environment to enhance seed development This

process is fast efficient and economical

32 Agricultural Gypsum Uses

Gypsum is used to treat soil as an amendment conditioner and fertilizer Gypsum is used

in a wide variety of agricultural applications

1 Gypsum improves soil texture and compacted soils

Calcium provided to the root zone combines sand silt clay and humus particles together

Thus water and air movement and plant root growth in the soil medium will be improved

(Chartres et al 1985 Greene et al 1988 Ilyas et al 1997) The compaction in soils can be

solved by application of gypsum especially when combined with deep tillage to break up the

compaction

2 Gypsum decreases bulk density of soil

Gypsum applications decrease bulk density of soil (Southard et al 1988) Untreated soil

by gypsum has a higher bulk density Many of the effects of gypsum however are limited to

shallow depths

3 Gypsum stops water runoff and erosion and soil crusting

Erosion begins when rain or irrigation drops strike bare soil detaching soil particles

Aggregates stabilized by gypsum are less prone to crusting and erosion since there is limited

runoff due to larger more stable aggregates (Gal et al 1984)

4 Gypsum improves swelling clays

Swelling clays and therefore swelling clay soils can be effectively treated by gypsum

(Mandal and Mandal 2002 Yilmaz and Civelekoglu 2009) As sodium is replaced by

calcium on these clays they swell less and therefore do not easily clog the pore spaces

through which air water and roots move Gypsum improves the expansive clay soils

significantly only up to an addition of 5 above this amount improvement being much less

significant and warranted by the increased cost of the gypsum involved

5 Gypsum increases value of organics

The use of gypsum helps rebuild the supply of soil organic matter and is a major means

for increasing the efficiency of its accumulation

6 Gypsum counteracts subsoil acidity

Gypsum leaches into the subsoil replacing aluminum and other acid forming ions thus

allowing roots to penetrate the hostile subsoil more readily

7 Gypsum helps reclaim sodic soils

Gypsum amends and reclaims soils high in destructive sodium and magnesium Sodium

and magnesium act the opposite as calcium in soils by destroying structure and reducing

water and air movement and root growth (Ilyas et al 1997)

8 Gypsum decreased ph of sodic soils

Gypsum has a substantial advantage for use in high pH or alkaline soils because of being

pH neutral This is because the sulfur in the compound lowers soil pH The presence of

gypsum in calcareous soils causes a small decrease in pH through the increased Ca2+

concentration in soil solution which would be expected to decrease the sorption of P

(Kordlaghari and Rowell 2006)

9 Gypsum enhances water use efficiency

Twenty five to 100 percent more water is available to crops depending on the soil type

and soil management practices Gypsum improves drainage through particle flocculation

10 Gypsum makes it possible to use low quality irrigation water

Gypsum should be applied to the soil or the irrigation water when soils or water are low

in total dissolved salts When the electrical conductivity of soils and water is low (~075 dSm

or less) surface soil sealing and water penetration problems occur if irrigation water does not

contain adequate calcium

11 Gypsum replaces harmful salts

Sodium chlorine boron and many other salts in higher levels in irrigation water and soil

are detrimental to plant growth and development since they rupture and destroy plant cells

Calcium from gypsum has a significant role in preventing the uptake of Na by plants

12 An excellent fertilizer source for calcium and sulfur

There are 16 nutrients required or essential for plants Calcium and sulfur are two of

them With calcium and sulfur deficiencies appearing more and more frequently gypsum is a

practical and economical source for these two nutrients

13 Gypsum helps with high bicarbonate irrigation water

Bicarbonates form free lime when water evaporates resulting in reduced available

calcium and increased soil pH The reduction of available calcium also leads to loss of soil

structure and reduced water infiltration

14 Gypsum makes slightly wet soils easier to till

Soils treated with gypsum have a wider range of soil moisture levels It is safe to till these

soils without danger of compaction or deflocculation

15 Gypsum prevents water logging of soil

Gypsum can improve the ability of soil to drain and not become waterlogged due to a

combination of high sodium swelling clay and excess water Infiltration rate and hydraulic

conductivity will be improved with the application of gypsum This will enhance the ability

of soils to have adequate drainage

16 Gypsum helps earthworms to flourish

A continuous supply of calcium with organics is necessary to earthworms Earthworms

improve soil aeration soil aggregation and mix the soil and can do the plowing for no-till

agriculture

4 GYPSUM PRODUCTION

The production of gypsum from 2006 to 2009 in selected countries in the world is

depicted in Table 1 More information about the world gypsum production is available at

(httpmineralsusgsgovminerals) The top producing countries of gypsum in 2009 in

descending order are China Iran Spain United States Thailand Japan and Canada

Production of gypsum in recent years follows the global economy

Gypsum resources are large and widely distributed Global crude gypsum production in

2009 was estimated to be 152 Mt compared to 159 Mt produced in 2008 (Table 1) Global

production of gypsum in 2007 was the highest compared to one before 2007 China is the

leading producer of crude gypsum in 2009 with an estimated 42 Mt followed by Iran with 12

Mt Spain with 115 Mt the United States with 94 Mt Thailand with 80 Mt Japan with 58

Mt and Canada with 55 Mt (Table 1) Iran supplies much of the gypsum needed for

construction in the Middle East Spain the leading European producer is considered the main

supplier of both crude gypsum and gypsum products to Western Europe It is probably that

China will continue to be the worldlsquos leading gypsum producer for the near future because of

the expansion of Chinalsquos economy and its respective construction and infrastructure demands

An increased use of wallboard in Asia coupled with new gypsum product plants amplified

production in that region North American contributes to almost 10 of total world

production of crude gypsum Most gypsum is used in the production of cement or as a plaster

product in countries of Asia and Middle East World production is likely underestimated

because output by some foreign gypsum producers is used to manufacture products on site

which may not be reported Moreover production of gypsum from small deposits in

developing countries was intermittent and in many cases unreported

Gypsum output is categorized as either calcined or uncalcined Calcined gypsum is

produced from crude gypsum to manufacture wallboard and plaster products Uncalcined

gypsum is mainly used in Portland cement production and agriculture The production of

crude and uncalcined gypsum in United States declined from 94 and 140 Mt in 2009 to 144

and 180 Mt in 2008 (Table 1) The leading States in producing crude gypsum were in

descending order Nevada Iowa California Oklahoma Texas Arkansas New Mexico

Indiana and Michigan The amount of gypsum used in Portland cement declined from 38 Mt

in 2006 to 33 Mt in 2007 Agricultural use of gypsum decreased from 25 Mt in 2006 to 17

Mt in 2007 Gypsum production in United States declined because of the continues falter of

the housing and construction markets continued to falter The construction of new wallboard

plants and the expansion of existing plants decreased in 2009

Synthetic gypsum is generated as a byproduct of various industrial processes Synthetic

gypsum is used as a substitute for mined gypsum principally for wallboard manufacturing

cement production and agricultural purposes Expansion of synthetic gypsum resources will

continue in the United States Studies indicate calcium limestone demand is expected to

increase by about 70 during the next 10 years Calcium limestone is the primary component

required to transform sulfur dioxide to synthetic gypsum

Gypsum resources in the United States are adequate but unevenly distributed The United

States import large amounts of gypsum from Canada to manufacture wallboard particularly

in the eastern and southern coastal regions Gypsum imported from Mexico is used for

wallboard manufacturing along portions of the United States western seaboard

During 2007 prices for gypsum wallboard generally decreased in response to a

corresponding sharp decrease in demand The average values reported by United States

producers were $818 per metric ton for crude gypsum and $2202 per ton for calcined

gypsum in 2007 The average value for calcined gypsum used in plaster products was $1845

per 100 kilograms The average value of uncalcined gypsum used in agriculture was about

$2690 per ton and that used in cement production was about $1429 per ton The steep drop

in prices of gypsum was due to the abrupt decline in the housing construction sector on which

the gypsum industry is heavily dependent In 2009 the average values per metric ton reported

by US producers in 2009 were $85 for crude gypsum and $400 for calcined gypsum

Demand for gypsum depends mainly on the activity of construction sector particularly in

the United States About 95 of the gypsum consumed in United States is used for building

plasters the manufacture of Portland cement and wallboard products Demand for gypsum

products is expected to decrease in the coming years as housing starts continue to drop

CONCLUSION

Gypsum can be distinguished by several physical and chemical characteristics Gypsum

is a valuable and important mineral that is needed in many aspects of our life It can be used

in different industrial and agricultural applications World resources of gypsum are large and

widely distributed The top producing countries of gypsum in 2009 in descending order are

China Iran Spain United States Thailand Japan and Canada Demand for gypsum products

is expected to decrease in the coming years because housing is expected to decline

REFERENCES

Blount C W amp Dickson F W (1973) GypsumndashAnhidrite Equilibria in Systems CaSO4 ndash

H2O and CaCO4 ndashNaClndashH2O American Mineralogist 58 323-331

Butler G P (1969) Modern evaporite deposits and geochemistry of coexisting brines the

sabkha Trucial coast Arabian Gulf Journal of Sedimentary Petrology 39 70-78

Chartres C J Greene R S Ford G W amp Rengasamy P (1985) The effect of gypsum on

macroporosity and crusting of two red duplex soils Australian Journal of Soil Research

23 467-479

Clark R N Swayze G A Gallagher A King T V V amp Calvin W M (1993) The U S

Geological Survey Digital Spectral Library Version 1 02 to 30 microns US

Geological Survey Open File Report 93-592 httpspeclabcrusgsgov 1340 pages

Cloutis E A Craig M A Mustard J F Kruzelecky R V Jamroz W R Scott A

Bish D L Poulet F Bibring J P amp King P L (2007) Stability of hydrated

minerals on Mars Geophysical Research Letter 34 L20202 doi101029

2007GL031267

Deer W A Howie R A amp Zussman J (1992) An Introduction to The Rock-Forming

Minerals Harlow Essex UK

Drake N A (1997) Recent aeolian origin of surficial gypsum crusts in southern Tunisia

geomorphological archaeological and remote sensing evidence Earth Surface Processes

and Landforms 22 641-656

Ford D amp Williams P (1989) Karst Geomorphology and Hydrology Chapman amp Hall

LondonGutieacuterrez F 1994a Geomorfologacuteıa de la Regioacuten de Calatayud El Karst en

Yesos MsC Thesis Zaragoza University Spain

Fryberger S G (2002) Geological overview of White Sands NationalMonument Online at

httpwwwnpsgovwhsaGeology

Gal M Arcan L Shainberg I amp Keren R (1984) Effect of exchangeable sodium and

phosogypsum on crust structure-scanning electron microscope observations Soil Science

Society of America Journal 48 872-878

Golden D C Ming D W Morris R V amp Mertzman S A (2005) Laboratory-simulated

acid-sulfate weathering of basaltic materials Implications for formation of sulfates at

Meridiani Planum and Gusev Crater Mars Journal of Geophysical Research 110

E12S07 doi1010292005JE002451

Greene R S B Rengasamy P Ford G W Chartres C J amp Miller J J (1988) The

effect of sodium and calcium on physical properties and micromorphology of two red-

brown earth soils Journal of Soil Science 39 639-648

Hardie L A (1967) The gypsumndashanhidrite equilibrium at one atmosphere pressure The

American Mineralogist 52 171-199

Holland H D amp Malinin S D (1979) The solubility and occurrence of non-ore minerals In

H L Barnes (Ed) Geochemistry of Hydrothermal Ore Deposits 461ndash509 New York

John Wiley

Hunt G R Salisbury J W amp Lenhoff C J (1971a) Visible and near-infrared spectra of

minerals and rocks IV Sulphides and sulphates Modern Geology 3 1-4

Ilyas M Qureshi R H amp Qadir M A (1997) Chemical changes in a saline-sodic soil

after gypsum application and cropping Soil Technology 10 247-260

Jackus L (1977) Morphogenetics of Karst Regions Bristol Adam Hilger

Kordlagharia M P amp Rowell DL (2006) The role of gypsum in the reactions of phosphate

with soils Geoderma 132 105-115

Kyle J K (1992) Evaporites evaporitic processes and mineral resources In JK Melvin

(Editor) Evaporites petroleum and mineral resources Elsevier New York 556

Lane M D amp Christensen PR (1998) Thermal infrared emission spectroscopy of salt

minerals predicted for Mars Icarus 135 528-536

Langford R P (2003) The Holocene history of the White Sands dune field and influences

on eolian deflation and playa lakes Quaternary International 104 31-39

Lindberg J D amp Smith M S (1973) Reflectance spectra of gypsum sand from the White

Sands National Monument and basalt from nearby lava flow The American Mineralogist

58 1062-106

Mandal P K amp Mandal T K (2002) Anion water in gypsum (CaSO42H2O) and

hemihydrate (CaSO412H2O) Cement and Concrete Research 32 313-316

Nettlejohn W D Nelson R E Brasher B R amp Derr P S (1982) Gypsiferous soils in the

Western United States Soil Science Society of America Proceedings 10 147-168

Ponsjack E (1940) Deposition of calcium sulphate from sea water American Journal of

Science 239 559-568

Schreiber B C amp El Tabakh M (2000) Deposition and early alteration of evaporites

Sedimentology 47 215-238

Schreiber B amp Schreiber E (1977) The salt that was Geology 5 527-528

Schuumltt B (1998) Reconstruction of palaeoenvironmental conditions by investigations of

Holocene playa sediments in the Ebro Basin Spain preliminary results Geomorphology

23 273-283

Shearman D J (1985) Syndepositional and late diagenetic alteration of primary gypsum to

anhydrite 6th Int Symp Salt The Salt Institute 1 41-55

Sonnenfeld P (1984) Brines and Evaporites Orlando Academic Press

Southard R J Shainberg I amp Singer M J (1988) Influence of electrolyte concentration on

the micromorphology of artificial depositional crust Soil Science Society of America

Journal 145 278-288

Spencer R J (2000) Sulfate minerals in evaporite deposits Reviews in Mineralogy and

Geochemistry 40 173-192

Stumm W amp Morgan J J (1970) Aquatic Chemistry New York Wiley-Interscience USA

gypsum Online at httpwwwusagypsumcom USGS minerals information Online at

httpmineralsusgsgovminerals

Verhaye W H amp Boyadgiev T G (1997) Evaluating the land use potential of gypsiferous

soils from field pedogenic characteristics Soil Use and Management 13 97-103

Warren J K (1982) The hydrological setting occurrence and significance of gypsum in late

Quaternary salt lakes in South Australia Sedimentology 29 609-637

White W B (1988) Geomorphology and Hydrology of Karst Terrains Oxford Oxford

University Press

Yilmaz I amp Civelekoglu B (2009) Gypsum An additive for stabilization of swelling clay

soils Applied Clay Science 44 166-172