ROCZNIKI GLEBOZNAWCZE, T. X X X II, NR 3, W ARSZAW A 1981
JERZY M A RC INEK , A N N A LA N G I ER- K UŻNI ARO W A , W OJCIECH CIEÔLA
CLAY MINERALS OF ALLUVIAL SALINE SOILS IN SHATT AL-ARAB REGION (SOUTHERN IRAQ)
S o il D iv isio n , In stitu te for Land and F orest R eclam ation , A g ricu ltu ra l U n iv e r sity of P ozn ań
G eology In sty tu te at W arszaw a
Soil D iv isio n , A g ricu ltu ra l In stitu te, T e ch n ica l-A g n icu ltu ra l U n iv e r sity of B yd goszcz
Previous investigations showed the presence of m ontm orillonite, illite, v.nd chlorite, as dom inant m inerals in the clay fraction of alluvial soils of Iraq [1, 3, 7]. Besides, these investigations showed the presence of small quantities of verm iculite, palygorskite, quartz, calcite and regularly and random ly interstratified system of expandable layer silicates w ith chlorite and mica [1, 3, 7]. These earlier reports include investigations of clay m ineralogy of alluvial sediments in north ern and middle Tigris and Euphrates Alluvial Plains [1, 2, 3, 4, 7]. There are no reliable invest igations of clay fractions of alluvial sediments from southern p art of Mesopotamian Plain i.e. from M arsh and Hor, Estuary and Tidal
sediments [2].
The aim of this paper is to present data of m ineralogical and chemical
analysis of carbonate-free clay fraction (less than 0 . 0 0 2 mm equivalent
spherical diameter) of six samples taken from Torrifluvents and Salor- thids developed on different alluvial sediments from southern Iraq, to provide a means of understanding the soil properties and to determ ine
the m ineralogical fam ily in soil taxonom y classification [9].
M A TE R IA L A N D M ETH ODS
Samples from six soils were analysed, nam ely A l-Sikhrijah, Abu Al-Khaseeb, K ut Swedi, Dimne, Seebah and Nashwah. The locations
are shown in Fig. 1, and some of the form ation factors are listed in
Table 1. These soil series have been described in detail in “S h att A l-Arab Project — Feasibility Report, Vol. Ill and IV : Soil Survey and Hydro- logical Investigations/’ Baghdad 1979. The morphology of soil samples
F ig. 1. M ap of p h y sio g ra p h ic u n its of S o u th -E a st Iraq (after P. B u rin gh 1960, m od ified ) and lo ca tio n of th e so ils in v estig a ted
1 — R iv er L e v e e , 2 — E stu ary R iv er L e v ee, 3 — S ilte d T id al F lat, 4 — T id al F lat, S — M arshes, 6 — S ilte d Ног and M arshes, 7 — C oastal F la ts, 8 — C oastal B e a ch , 9 — D esert, W eld ies, io —
San d D u n e, 11 — lo c a tio n o f so ils p r o file s
is listed in Table 2A, and the selected chemical data of the samples are presented in Table 2B.
P article size separation and chemical analysis of clay fraction were
made by the m ethod of J a c k s o n [5, 6]. Therm al analysis were car
ried out on Na-clay w ith derivatograph to receive three curves i.e. differential therm al (DTA), derivative therm ogravim etric (DTG), and
therm ogravim etric (TG) curves [8].
D iffractogram s were made by means of Rikagu-Denki X -ray dif fractom eter. Sample preparations for diffraction included :
1) N a-saturated, free-carbonates ;
2) N a-saturated, free-carbonates, parallel orientation ; 3) N a-saturated, free-carbonates, ethylene glycol saturated ; 4) N a-saturted, free-carbonates, heated at 500°C for 1 hour.
V ariant 1 and 2 were made in a broad range of 0 angle, whereas variant 3 and 4 in a narrow one.
Clay minerals of alluvial saline soils 185 T a b l e 1 S o i l fo r m a tio n f a c t o r s o f i n v e s t i g a t e d S o i l S u b g ro u p s1 S o i l sam ple No. P r o f i l e Но. S o i l s e r i e s G re a t s o i l su b g ro u p L o c a tio n P h y sio g ra p h y P a re n t m a t e r i a l R e l i e fD ra in a g e c o n d i t i o n s 1 61 A I - S i k r i j a h зо11 T i g r i s R iv e r Levee; S l i g h t l y e l e v a t e d V e r t i c .T o r r i f l a m e n t s T i g r i s A lluvium o v e r s u r ro u n d in g M arsh es;
K a ssa ra h e l e v a t i o n 2 .5 to 4 .5 m a . s . 1 . }
w e ll d ra in e d
2. 105 Abu A l-K haseeb s o i l S h a tt A l-A rab P l a t a r e a u n d e r th e in f l u e n c e V e r tic T o r r i f l u v e n t s E s tu a ry Levee; o f f i d a l e f f e c t s ; e l e v a t i o n 1 .5 Abu "Àl-Khasèe b... Shatt* A l-ЛгаЪ
A lluvium to 3 .0 m a . s . l . ; m o d e ra te ly w e ll d r a in e d 3 43 Kut Swedi s o i l I r r i g a t i o n S i l t e d P l a t V e r t i c T o r r i f l u v e n t s T i d a l F l a t e l e v a t i o n 2 .5 to 3*5 m a . s . l . ; e x tre m e ly s a l i n e • T i g r i s and S h a tt w e ll d ra in e d
K ts ib a u A l-A rab Alu7ium
4 85 Dimne s o i l I r r i g a t i o n D e p re ss io n , L o c a l D e p re ss io n 0 ,5 to 1 .0 m V e r t i c T o r r i f l u v e n t s T i g r i s and S h a tt loTrer th a n th e s u r r o u d i r g T i d a l Nashwah A l-A rab A lluvium F l a t ; i m p e r f e c t l y o r somewhat;
p o o rly d r a in e d i
5 100 S eebah c o i l T i d a l F J a t , F l a t ; e l e v a t i o n 0 .5 to 2 .5 о T ypic S a l o r t h i d s T i d a l A lluvium a . s . l . ;
Seoboh m o d e ra te ly w e ll d r a in e d
6 73 Na.'jh.Tah s o i l Form er S i l t e d F l a t L o c a l D e p re n sio n ; V e r t i c T o r r i f l u v e n t s H or; e l e v a t i o n 0 .0 to 2 ,0 m a . s . l . ;
Qurna S h allo w Lake S e d i
m ents o f E u p h ra te s p o o rly d ra in e d x C lim at e o f th e R egien : d ry and h o t сш лсегз end w et c o l d - w i n t e r s , r a i n f a l l 12fc» сю/ y e a r , e v a p o r a t i o n - = 2038 mm/year,-msan a n n u a l a i r te m p e ra tu re = 2 4 .2 °C , m ean'sum m er a i r te m p e ra tu re =« 3 3 . 4QC, mean tf ï n t .ë ÿ .e i r te m p e ra tu rę . »! 13.4°СГ. _
Some chemical elements (S i02) A120 3, Fe20 3, MgO, K20 ) of clay
fraction were determ ined by bringing the elem ents into solution by
fusing them in Na2C 03 (Jackson 1960). In the solution F e203 and MgO
were determ ined by ASA Pye-Unicam apparatus, A1203 colorim etrically
w ith aluminon, K20 by flame spectrophotom eter, and S i02 by gravi
m etric method. Cation exchange capacity (CEC) of the clay fraction was
determ ined by J a c k s o n m ethod [6].
R E SU L T S A N D D ISC U SSIO N
Therm al analysis of all the samples gave sim ilar DTA, TG and DTG curves and confirmed that, the m ineralogicąl composition of the
inves-T a b l e 2 Л. ''.c i l .T'-jrpleo d e s c r i p t i o n
.iumplc
У*о. P r o f i l e No. H orizon Depthcm C o lo r T e x tu re S t r u c t u r e C o n sis te n c e
1 01 С 2 55-100 7.5YR4/3 s i c 2m зЬк в f i - w vp 2 105 Cl 2 5 - 55 7.5YK4/3 s i c 2f-m 3bк /6 1 . o r / m f r - -я тр 3 43 С 2 за 30- 50 7.5*K >/4 n ie if- m abk/ с г / m f r - w p 4 35 C1 12- 63 7 .5 ÏK 4 /3 с Im- c abk и f i - t p
Г 100 C?oa 4 5- 70 7.5YK4/4 s i c Ac p r - m abk m f i — » p
6 70 C3 55- 90 7 .5 ÏR 4/4 г. i с Г abk a r f i - w 7p C boaâr;.! cUt.?. Sample No. S i l t % C lay /О Lime % Gypotun % pH /p ? .s to / EC c mmhos/cr.
•vat e r e x ;:ra c t C.rom s a t u r a t e d p a s te 3AR С a I Kg Na j HCO^ Cl so a t ?5°C mo /1 1 58 40 25 0 . 1 7 . 3 4 . 7 13 13 31 13 25 26 9 2 50 42 40 0 . 2 7 . 7 5 . 2 36 20 53 19 3 7 18 5 3 50 44 26 1 . 7 7 . 5 • 9 66 1 03 504 16 3ÖO 97 55 4 39 5 3 33 0 . 5 7 . 7 9 . 2 33 60 61 0 50 29 9 5 55 43 31 0 . 7 8 . 0 6 2 . 1 19 66 59 2 11 7 58 79 91 6 46 4S 40 0 . 8 8 . 1 1 1 . 6 51 13 96 10 72 no 17
tigated clay fraction is supposed to be similar. The following therm al effects appeared on the curves :
— strong endothermie at 50 to 200°C connected w ith the loss of water (about 7°/o of weight),
— exothermic, w ith maxim um at 300°C, and m inimum loss of weight (except sample 5 which lost about 2°/o of its weight),
— broad group of endotherm ie effects at 440 to 750°C which con sists of several sm aller connected effects giving total w eight loss about
7% for samples 2, 4, 5, 6, a nd at 390 to 710°C for sample 3, and at 380
to 640°C for sample 1,
— exotherm ic effects at about 820 to 850°C.
The first of the m entioned effects comes from the loss of free w ater and it is most common. The second effect (exothermic) is probably con nected w ith crystallization of ferric oxide gels. This effect was precided by a small loss of w eight which comes from dew atering of ferric hydro- oxides. The th ird effect being a group of endotherm ie effects, of which the first at about 500 to 600°C comes from palygorskite, the second at about 600 to 700°C comes from m ontm orillonite and chlorite, b u t its
final phase for the samples 2, 4 and 6 comes from calcite. The fo u rth
exotherm ic effect probably comes from palygorskite.
X -ray diffraction p atterns of the investigated clay fraction show great sim ilarities of the diffraction spacing at 14 Â, 10.5 Â, 10Â, 7Â and 6.4À and at a higher spacing, coming from clay m inerals. The next
Clay minerals of alluvial saline soils 187 group of peaks comes from quartz (3.33 A), calcite (3.03 A), ferric hydro oxides (2.70 Â), occassionally halite (2.81 Â), and gypsum (3.07 Â). On the basis of dhki values, and changes of peaks after ethylen glycol satu rated samples and after heating them up to 500°C (Figs 3 and 4), the
Fig. 2. D iffe r e n tia l th erm al (DTA), d e r iv a tiv e th erm o g ra v im etric (DTG), and th erm o g ra v im etric (TG) cu rv es for sa m p les of the Shatt. A l-A ra b R eg io n so ils
diffraction spacing coming from clay m aterials, m ay be classified as belonging to the following : at 14 Â to chlorite, m ontm orillonite, and some m ixed-layer, at 10.5 À to palygorskite-, at 10 Â to illite, at 7 À to chlorite, and at 6.4 A to palygorskite. The broadness of the peaks, their asym etry etc. for the natural and prepared samples confirm the presence of m ixed-layer clay minerals.
The investigated clay fraction contains 2.98 to 4.29% K 20 (Table 3). As in jthis case K20 m ay only be connected w ith illite, so this clay m ineral seems to be dom inant of the analysed clay fraction. The
contents of illite (46 to 6 6% ) shown in Table 4 were calculated on the
basis of K20 content of the clay fraction, assuming th a t the average K 20 content in illite is 6.5% [9, 10].
Chlorite, being probaly MgO rich variety (see Table 3), is a constant component of the investigated clay fractions; its contents are much sm aller than the illite. It m ay appear as an individual clay m ineral or in terstratified w ith m ontm orillonite.
Palygorskite is also a constant component of clay fraction of all the investigated samples.
M ontmorillonite content in the clay fraction is sm aller than any other clay m ineral. As a pure m ineral it appears sporadically, b ut it makes interstratified system of expantable layers w ith illite and chlorite.
Ferric hydrooxides, and probably ferric oxides, of the investigated clay fraction are predom inantly amorphous compounds so they were
Fig. 3. X -r a y d iffra ctio n p a ttern s of. th e clay fra ctio n ( < 2 fim) from rep résen ta tiv e soil sam p les of th e S h a tt A l-A ra b R egion
A — p a r a lle lly o rien ted on glass, В — e th y le n e g ly c o l sa tu ra ted , С — h ea ted ąf 500°C
not detected by X -ray diffraction at 2.70 Â, bu t on the differential therm al (DTA) curves they gave an exotherm ic effect at about 300°C. Their approxim ate quantity was calculated on the basis of chemical determ ination of Fe20 3 in the clay fraction and diminished by 2°/o which is the consistent of clay m inerals (Table 3). Quartz, calcite and sporadic
ally halite and gypsum make altogether not mor than 2% of the clay fraction.
C lay m in erals of a llu v ia l sa lin e soils 189
Fig. 4. X -r a y d iffra ctio n p attern s of the cla y fra ctio n ( < 2 {лт) from rep resen ta tiv e soil sam p les of the S h a tt A l-A ra b R egion
A — p a r a lle lly o rien ted on g la ss, В — e th y le n e g ly c o l sa tu ra ted , С — h ea ted af 500°C
Г a b 1 e 3 C hem ical a n a l y s i s o f c la y f r a c t i o n / < 2 jcm/ Sample Ho. Наше 1 2 3 4 5 6 % o f c la y f r a c t i o n S i° 2 4 1 .4 0 4 0 .4 4 4 3 .0 0 3 9 .5 2 4 4 .4 4 34 .6 8 a i2o3 11 .3 3 6 .4 2 3 .6 9 7 .5 6 11.71 8 .5 0 F e 2° 3 6 .8 6 5 .9 4 5 .9 4 6 .1 7 6 .6 9 5 .8 0 MgO 1 4 .5 9 1 7 .5 7 19.56 18.9 0 1 6 .2 4 1 6 .5 8 K2° P °3 4 .1 9 3 .0 5 4 .2 9 3 .85 3 .8 5 CECX 34*5 2 6 .5 3 6 .4 31.1 2 6 .0 27 .1 F e -h y d r o o x id ea 5 4 4- 4 5 4
x CEC = C a tio n Exchange C a p a c ity i n я е /1 0 0 g c la y
C O N C LU SIO N S
The clay m ineralogy of A lluvial Saline Soils in S h att A ll-A rab Region, Southern Iraq, was studied. Illite as a dom inant clay m ineral (46 to 66 per cent) of the clay fraction of all the investigated soil samples was found. In sm aller quantities chlorite, polygorskite, m ont- m orillonite and m ixed-layer clay m inerals, m aking altogether 28 to 47 per cent of the clay fraction appeared. In spite of different conditions of sedim entation (origin of sediments, drainage conditions, salinity, etc.) of the investigated soils, clay fraction shows high sim ilarities in
T a b l e 4 A p p r o x i m a t e compcci-ïion o f c l a y f r a c t i o n S o i l enuaple Ho. I.U .U c % Qiiairc, n f i l c i t * . , gypauiü, e t c . % O th e r c l a y m in e r a ls a p p ro x ia a i-e % m in e r a l com ponentr, 1 4t / ~ 2 / 47 с , /1 «tc~ 1 --IÂÎ/, Сш, PAL / + / * о 64 / - 2 / 30 С, /14С-14М/,Са, Г.Л. А ;- ь / 3 47 / - 2 / 47 С, / 1 C - -14M/, PAL / r * / 4 66 / - 2 / 2 0 (-,C“/14C-14M/, PAL / т - y ï / 5 5 S / - 2 / 34 С,С-/14С-14^1/, PAL / + » / 6 5 9 / - 2 / / С /, / 1 4 С - 1 4 М / / Ю - 1 4 И / , y.X t p a l / h - / x E x p l a n a t i o n o f e y m b o l s : С = c h l o r i t e , С = c h l o r i t e c o n t e n t s m o r e t h a n u s u a l , / 0 / = c h l o r i t e c o n t e n t s l e s s t h a n u s u a l , S m - S m a c t i t a , P A L - P a l y g o r s k i t e , c o n t e n t s o f i / + / s m a l l , Л - + / m e d i u a , / т л + / hi^ h, i n b r e c k e t s - m i x e d l a y e r s oft 14C - c h l o r i t e , 1 4M - m o n t a o r i l l o n i t e , 10 - ii l i t e , M x = o t h e r v e r y c o m p l i c a t e d m i x e d l a y e r s .
composition. According to the SOIL TAXONOMY (1975) criteria all the investigated soils can be classified to m ineralogical class as to the c l a y e y i l l i t i c f a m i l y .
R EFEREN CES
[1] A 1 - R a w i, A. II., J a c k s o n M. L., H o l e F. D. : M in eralogy of som e arid and sem iarid land soils of Iraq. S o il Sei. 6, 1969, 480-486.
[2] E l - D a g h i s t a n i , D o u g r a m e j i J., A l - N a k i b Z., T a k e s s i a n B. A., A 1 - T a w i 1 B., v a n — A a r t R. : F e a sib ility S tu d y on the D ev elo p m en t of th e S h a tt A l-B a sra h C anal P roject. T ech. B u ll. 41, 1972, IA R N R , Baghdad. [3] H a n n a A. B., R i h a n y F. A. : T yp es of cla y m in era ls in an a cid ified c a l careous soil of Iraq. Trans. Int. Soc. S o il S ei. 8th Cong., B ucharest 3, 1964, 1277-1285.
[4] H a r r i s S. A. : T he g ilg a i and b a d -stru ctu red soils of cen tra l Iraq. J. Soil Sei., 9, 1958, 169-185.
[5] J a c k s o n M. L. : S o il ch em ical a n a ly sis — ad van ced course. D ept. S oil Sei., U n iv. W iscon sin , M edison 1956.
[6] J a c k s o n M. L. : Soil C hem ical A n a ly sis. P r en tic e-H a ll, Inc. E nglew ood C liffs, N. J. 1960.
[7] К a d d o u N. S. : C lay m in era lo g y of som e a llu v ia l soils of Iraq and D u b u qu e silt loam and u n d erly in g d o lo m ite lim esto n e of W isconsin. Ph. D. th esis., U n iv . W iscon sin , M edison 1960.
[8] R i c h C. I., K u n z e G. W. (E d.): Soil C lay M inerology — A Sym posium . U n iv. N orth. C orolina P ress. C hapel H ill 1964.
[9] S oil S u r v e y S ta ff. : S o il T a x o n o m y . A gric. H andb. 436. U. S. G ovt. P rin tin g O ffice, W ash in gton D. C. 1975.
[10] W eaver C. E., P ollard L. D. : T h e C h em istry of C lay M inerals. E lsev ier Sei. P ub. Co., A m sterd a m —L ondon—N e w Y ork 1973.
Clay minera ls oi' alluvia l saline soils 191
J. M ARCINEK, A . LAN GIER-K UŻN IARO W A, W. CIEŚLA
M IN ERA ŁY IL A ST E A LU W IA LN Y C H G LEB SŁO N YC H R EG IO N U SH ATT A L -A R A B (PO ŁU D N IO W Y IRAK )
In sty tu t M elioracji R oln ych i L eśn y ch A R w P ozn an iu In sty tu G eo lo g ii w W arszaw ie
A k ad em ia T ech n iczn o -R o ln icza w B yd goszczy
S t r e s z c z e n i e
P rzep row ad zon o bad an ia nad sk ład em m in era lo g iczn y m fra k cji ila stej (2 |лт) sześciu próbek g leb o w y ch c h a ra k tery sty czn y ch dla osad ów a lu w ia ln y c h p o łu d n io w ej części D oln ej M ezopotam ii. W yn ik i tych badań w y k a za ły , że d om in u jącym m in era łem ila sty m badanej fra k cji jest illit (46-66% fra k cji ila stej). S ta ły m i sk ła d n ik a m i tej fra k cji są ponadto: ch loryt, p a ły g o rsk it, m o n tm o ry llo n it oraz stru k tu ry m ieszan e; ich zaw artość w y n o si 28-47% fra k cji ila stej. S tru k tu ry m ie szan e tw o rzy g łó w n ie m on tm orylon it z ch lo ry tem i illite m . We fra k cji badanej sp otyk an o ponadto w o d o ro tlen k i żelaza, a być m oże i tlen k i żelaza, k tórych o r ien ta cy jn a zaw artość w y n o si 4-5% . K w arc, k a lcy t oraz sp orad yczn ie gip s i h a lit w su m ie n ie przek raczają 2% fra k cji ila stej. A lu w ia ln e g leb y p o łu d n io w eg o Iraku n a le ż y zatem za k la sy fik o w a ć, w ed łu g S o il T a x o n o m y 1975, do rod zin y illito w y c h g leb ila sty c h (cla y ey illitic soil fam ily).
D oc. dr J er zy M arcinek I n s ty tu t M elioracji Poznań, ul. N oskow skiego 8
