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Article

Mineralogy, Geochemistry and Stable Isotope Studies of the Dopolan Bauxite Deposit, Zagros Mountain, Iran

by
Somayeh Salamab Ellahi
1,
Batoul Taghipour
1,*,
Alireza Zarasvandi
2,
Michael I. Bird
3 and
Alireza K. Somarin
4
1
Department of Earth Sciences, Shiraz University, Shiraz 7146713565, Iran
2
Department of Geology, Earth Sciences Faculty, Shahid Chamran University, Ahvaz 6135743136, Iran
3
College of Science, Technology and Engineering, Centre for Environmental and Sustainability Science, James Cook University, PO Box 6811, Cairns, Queensland 4870, Australia
4
Department of Geology, Faculty of Sciences, Brandon University, Brandon, MB R7A 6A9, Canada
*
Author to whom correspondence should be addressed.
Minerals 2016, 6(1), 11; https://doi.org/10.3390/min6010011
Submission received: 10 November 2015 / Accepted: 28 January 2016 / Published: 6 February 2016
(This article belongs to the Special Issue Mineral Deposit Genesis and Exploration)
Browse Figures
Versions Notes

Abstract

:
The Dopolan deposit is a Mediterranean-type bauxite located in the Zagros Fold-Thrust Zone, Iran. This deposit consists of five lithological members including iron-rich, clay-rich, oolitic, pisolitic and organic matter-containing bauxites. The mineralogy of the deposit includes diaspore, boehmite, and kaolinite, nacrite, with minor pyrite, anatase and rutile. Geochemical studies show that light rare earth elements (LREEs) are enriched relative to heavy rare earth elements (HREEs) in all members, supporting an authigenic origin. Mass changes based on Ti as an immobile element indicate that conventionally-immobile elements (Al, Nb, Ta, Zr, Hf) are enriched in situ in the residual units, whereas mobile elements (K, Ca, Si) were depleted during bauxitization. This study shows that the Khaneh–Kat argillitic dolomite is the likely parent rock. The δ18O (7.63‰ to 9.35‰) and δD values (−49.91‰ to −66.49‰) for kaolinite in the bauxite samples suggest equilibration with meteoric waters which supports a supergene origin. Bauxitization occurred in a warm climate with relatively constant isotopic composition suggesting climate stability during the development of bauxite horizons and remobilization of Al (with formation of secondary boehmite). The δ13C values of calcite (−7.3‰) in the bauxite support the idea that the Khaneh–Kat Formation has experienced post-depositional isotope exchange with meteoric waters during the karstification process.

1. Introduction

Residual and concealed bauxites are two important sedimentary aluminum deposits. Residual bauxite deposits are classified as karst bauxite and laterite type bauxite [1]. Karst bauxite deposits from the Mediterranean region and other worldwide bauxite formations have been investigated by a number of authors [2,3,4,5,6,7,8,9,10,11]. Karst bauxite genesis is related to paleo-weathering products derived from different rocks types including carbonate rocks, marl, volcanic and magmatic rocks [12,13,14,15,16,17].
Karst bauxite deposits are commonly characterized by high content of Al2O3, TiO2, high field strength elements (HFSE), and abundant detrital minerals such as zircon, tourmaline and rutile [11,18,19]. The mobility and behavior of elements during bauxitization have also been discussed by a number of researchers [8,11,14,17,18,19,20,21,22]. To investigate mobility of elements in weathered systems, various methods have been discussed by some researchers [10,14,23,24,25]. Formation of bauxite horizons in the Phanerozoic was a climate dependent process; it has been established that the Phanerozoic bauxites were generally formed in hot or warm humid climates [26]. These conditions allowed intensive weathering of carbonate rocks, karstification and subsequent bauxite development [26].
Stable isotopes (H, C and O) have been used to study bauxite genesis and indirectly determine paleo-environments associated with its formation [27]. The δ18O and δD values of minerals such as kaolinite, goethite, gibbsite and boehmite can be used to deduce information about the conditions that prevailed during bauxitization [28]. Hydrogen isotope ratios may be affected by post-formation isotope exchange with meteoric water at low surficial temperature or higher temperatures as a result of diagenetic conditions [29]. Carbon isotope composition of organic matter can indicate the role of microbial activity during deposition and mineralization of carbonate which may reflect environmental conditions and biogeochemical processes that controlled the formation of bauxite [30].
The most important known bauxite deposits in Iran are distributed in four regions, namely: (1) Sanandaj–Sirjan belt, Permo–Triassic and late Triassic in Bukan and Kanshiteh; (2) The Zagros Fold belt, Upper Cretaceous, Triassic in Mandan, Deh-now, Sarfaryab and Dopolan [9]; (3) The Alborz mountains, Upper Triassic in Tilabad and Jajarm [31]; and (4) The central plateau of Iran, Upper Triassic, Permo-Triassic in Bazargan and Balbaloyeye [31] (Figure 1).
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Figure 1. Schematic map of Iran with location of the Zagros Fold Belt, Alborz Mountain, Central Iran, and distribution of bauxite deposits.
Figure 1. Schematic map of Iran with location of the Zagros Fold Belt, Alborz Mountain, Central Iran, and distribution of bauxite deposits.
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The Triassic Dopolan bauxite deposit is located in the Chaharmahal and Bakhtiary province in a high Zagros structural zone. The Dopolan bauxite deposit has an estimated reserve of 8–15 million tons with an average grade of 45% Al2O3 [32]. Previous studies of the Dopolan bauxite deposit show that the bauxite formed as a continental deposit filling karstic cavities at the boundary of the Khaneh–Kat and Neyriz Formations [33]. The aim of this study is to determine the precursor rock and understand the bauxitization process during formation of this deposit. To attain these objectives, detailed geological, mineralogical, petrographical and geochemical investigations (including 18O and D isotopes) were carried out and the results are discussed here.

2. Geology

The Dopolan deposit is located in the High Zagros thrust zone near the border of Zagros and Central Iran zones. The structural framework of the thrust zone is complex, with significant folding and faulting. The Zagros fold belt evolved during the collision event between the Arabian and Eurasian plates [34] during late Cretaceous [35] and Pliocene [36].
The Zagros orogenic/metallogenic belt extends from the Turkish–Iranian border in NW to the Makran zone in SE Iran [37]. This belt consists of five tectonically related parallel zones: Zagros simple folded belt, the “Crushed zone” or High Zagros, the Main Zagros thrust, the Sanandaj–Sirjan zone, and the Urumieh–Dokhtar magmatic arc [38]. The High Zagros is characterized by earlier deformation, large offsets on basement faults, steep contacts with surrounding zones and more ductile deformation [39] (Figure 1). The geomorphology of the Dopolan area is characterized by many mountain peaks, up to 2200 m high separated by deep valleys. The Dopolan bauxite is located in a large structure called the Sabzkuh–Kelar Synclinorium, which is bounded by two thrust faults. In the studied area, the Zagros stratigraphy consists of Cambrian to Quaternary sequences. The oldest strata are located on limbs and youngest rocks in the core of sycnclinorium, uplifted by faults [32].
In the Dopolan deposit, the lithostratigraphic column includes pinkish Permian dolomite (Dalan Formation) at the base, overlain by the Upper Triassic argillitic dolomite (Khaneh–Kat Formation), and Jurassic dolomite (Neyriz Formation) (Figure 2).
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Figure 2. Geological map of the Dopolan bauxite deposit [40].
Figure 2. Geological map of the Dopolan bauxite deposit [40].
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Argillite and bauxite ore layers lie above the Triassic brecciated argillitic dolomite (Figure 3A). The Khaneh–Kat Formation is predominantly composed of dolostone and marly limestone with a matrix of calcite (Figure 3B) [41]. This formation consists of a massive crystalline and porous dolomite at the top with more clay-rich carbonates and shale in the lower parts [42]. The Khaneh–Kat Formation is intensely karstified with bauxite filled karst and caves (sinkholes) at the top of the Khaneh–Kat Formation (Figure 3C,D). Karstification in the Khaneh–Kat Formation is the result of specific paleo-climatic regimes as climate and time are important to the development of extensive karst landforms [43]. The studied deposits are situated along a disconformity between the Khaneh–Kat and Neyriz Formations, implying extended periods of subaerial exposure (karstification, weathering, bauxitization).
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Figure 3. Field photograph of various karst features in the Upper Khaneh–Kat Formation: (A) Brecciated argillite; (B) Bauxite horizon and relationship with the Khaneh–Kat Formation (footwall dolomite); (C) Iron-rich bauxite-filled sinkhole in karst in the Khaneh–Kat Formation; (D) Karstified footwall filled with iron-rich bauxite detritus.
Figure 3. Field photograph of various karst features in the Upper Khaneh–Kat Formation: (A) Brecciated argillite; (B) Bauxite horizon and relationship with the Khaneh–Kat Formation (footwall dolomite); (C) Iron-rich bauxite-filled sinkhole in karst in the Khaneh–Kat Formation; (D) Karstified footwall filled with iron-rich bauxite detritus.
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The main bauxite horizon occurs at the contact of the Khaneh–Kat and Neyriz Formations where bauxite-filled paleo-sinkholes in the Khaneh–Kat Formation. The main bauxite horizon is composed of five distinct layers including (from bottom to top): iron-rich, clay-rich, oolitic (powdery white bauxite), pisolitic and organic-rich (black) bauxite layers (Figure 4).
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Figure 4. Schematic profile of the Dopolan bauxite deposit; on the right diverse bauxite facies.
Figure 4. Schematic profile of the Dopolan bauxite deposit; on the right diverse bauxite facies.
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The lower part of the bauxite horizon is comprised of iron-rich bauxite, ~1.5 m thick, which directly overlies the Khaneh–Kat Formation. The mineral assemblage of this unit is pyrite, kaolinite and boehmite [44]. Clay-rich, oolitic and pisolitic bauxite layers are intercalated between the iron-rich bauxite at the base and organic-rich bauxite at the top. The clay-rich bauxite, ~5 m thick, has grey to light grey color and shows fine-grained oolitic texture. It is the main ore zone with 53% Al2O3, 2% TiO2. Kaolinite, diaspore, boehmite and quartz as main minerals [32]. Field evidence such as presence of plant root casts show that the deposit formed in a marsh sedimentary basin. The clay-rich bauxite is overlain by the oolitic bauxite which is characterized by a vuggy structure, fine-grained (0.4–5 mm) oolitic texture, low density, with mineralogy dominated by diaspore and boehmite. Pisolitic bauxite, 0.5–3 m thick, overlies the oolitic bauxite. This layer contains 1–5 cm dark grey hard concretions with abundant diaspore and an average of 70% Al2O3, 3% Fe2O3 and 2% TiO2 [32]. The transition between the upper pisolitic bauxite and the lower part of the black organic-rich bauxite is gradual and indistinct. The average thickness of the organic-rich bauxite is 1.20 m with kaolinite, a small amount of nacrite and rutile, and abundant plant remnants, which are locally converted to small lenses or thin coal layers.

3. Methodology

Field investigations were carried out over two periods (2013–2014) during which 60 specimens were sampled from the bauxite quarry and argillite (Khaneh–Kat Formation). Thirty-four samples of the five identified bauxite horizons were selected for petrographic studies. A detailed mineralogical analysis of the bauxite samples was performed by X-Ray diffraction (XRD) at the Geological Survey of Iran (Tabriz center) using a Philiphs X pert Step-Tro Model D-5000 diffractometer (Philiphs, Amsterdam, The Netherlands) with Co Kα (1.789 Å) radiation, fixed graphite monochromators, voltage 40 kV current 30 mA, 0.02 step size, scan range 4°–80°, drive axis 2θ. Major and trace element content in the representative samples were obtained using inductively coupled plasma mass spectrometry (ICP-MS) in the Acme Analytical Laboratories, Vancouver, BC, Canada. Sample preparation was based on digestion of 0.2 g sample in lithium metaborate flux and fusion in a furnace at 1000 °C. The melt is then dissolved in 100 mL diluted HCl acid.
Before isotopic measurement, samples were crushed with mortar and pure minerals were separated using the method of Bird et al. (1992) [45]. Stable isotope analysis was carried out at Cornell Isotope Laboratory in the United States. Isotope ratios were determined using a high precision Thermo Delta V isotope ratio mass spectrometer (Bremen, Germany) interfaced to a Temperature Conversion Elemental Analyzer (TC/EA). Analyses were performed utilizing several in-house and commercial standards for internal checks on instrument accuracy and precision. Results for δ18O were compared against the Vienna Standard Mean Ocean Water (V-SMOW) [46]. Carbon isotope values reported in standard δ notation in units of per mil (‰) relative to the [46] Vienna Peedee Belemnite standard. The δ13C values were reproducible to ±0.2‰.

4. Mineralogy

Mineralogical and textural investigations based on optical microscopy and XRD analysis show that diaspore, kaolinite and nacrite are the main mineral components in the bauxite horizons with boehmite, anatase, rutile and muscovite as minor phases (Table 1). Diaspore is the dominant Al mineral found in the Dopolan bauxite. The matrix, authigenic in origin, shows predominantly pelitomorphic, microgranular and panidiomorphic textures; however, there are also some terrigenous grains such as intraclasts, ooids and erosional ooid nucleus which suggest an allochthonous origin for some components of the deposit. In addition, pelitomorphic and fluidal textures in this deposit suggest allochthonous bauxitization of the parent rock. This may be due to insufficient speed to remove dissolved silica that led to the kaolinite formation.
Two forms of pyrite occur in bauxite horizons: framboidal pyrite and euhedral pyrite (Figure 5A,B). Framboidal pyrite commonly forms during early diagenesis under organic-rich, anoxic conditions [7,11,47,48]. Euhedral pyrite occurs as cubic grain filling fractures and is interpreted to have formed during the last stages of diagenesis. Petrographic observations show the fragments in the central part of the pisolites are filled with the secondary porous matrix composed of kaolinite (Figure 5C,D). The pisolitic bauxite is characterized by the presence of pisolitic textures. Microscopic investigation suggests two pisolite forms: (1) simple pisolites with a kaolinite core surrounded by a preserved cortex of boehmite (Figure 5E); (2) complex residual rounded fragments typical of pisolitic bauxite, so called allogenic pisolites (Figure 5D) [49]. Micromorphological evidence such as pisolites with simple, complex and oolitic cores indicate that deposit can be divided into two types—autochthonous and allochthonous (Figure 5C–E).
Table
Table 1. X-Ray diffraction (XRD) mineralogical results and textural characteristics of selected samples of the Dopolan deposit.
Table 1. X-Ray diffraction (XRD) mineralogical results and textural characteristics of selected samples of the Dopolan deposit.
Sample No.Bauxite LayersMatrixMajor PhasesMinor Phases
Do-IRIron-rich bauxitePanidiomorphNacrite, Kaolinite, PyriteAnatase, Boehmite, Muscovite (< 10%), Rutile
Do-ClClay-rich bauxiteMicrogranularKaolinite, quartz, DiasporeBoehmite
Do-OoOolitic bauxiteunknownDiaspore, NacriteAnatase, Muscovite (< 10%), Rutile
Do-PiPisolitic bauxiteMacrocrystallineDiasporeAnatase, Nacrite, Muscovite, Rutile
Do-OrgOrganic-rich bauxiteunknownNacrite, Kaolinite, PyriteAnatase, Rutile
KhaDolomite, Khane katunknownCalcite, Dolomite, Montmorillonite-
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Figure 5. Microphotographs of the Dopolan deposit: (A) Euhedral and framboidal pyrite in the iron-rich bauxite; (B) Euhedral pyrite in the organic-rich bauxite; (C) Diaspore concretion in a porous matrix composed of kaolinite; (D) Complex residual rounded fragments typical of pisolitic bauxite; (E) Simple pisolite with a kaolinite core surrounded by a preserved cortex of boehmite; (F) Discolored pisolites showing deferrification process, kao = kaolinite, Dsp = diaspore.
Figure 5. Microphotographs of the Dopolan deposit: (A) Euhedral and framboidal pyrite in the iron-rich bauxite; (B) Euhedral pyrite in the organic-rich bauxite; (C) Diaspore concretion in a porous matrix composed of kaolinite; (D) Complex residual rounded fragments typical of pisolitic bauxite; (E) Simple pisolite with a kaolinite core surrounded by a preserved cortex of boehmite; (F) Discolored pisolites showing deferrification process, kao = kaolinite, Dsp = diaspore.
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5. Geochemistry

5.1. Major and Trace Elements

Whole rock major, trace and rare earth element (REE) analyses of bauxite horizons are provided in Table 2. The average of Al2O3 content of the Dopolan bauxites varies between 26 wt % and 72 wt %, while the average content of Fe2O3 and SiO2 commonly ranges between 1 wt % and 17 wt % and 1 wt % and 35 wt %, respectively (Table 2).
Table
Table 2. Major and trace element compositions of samples from the Dopolan deposit, Khaneh–Kat and Neyriz Formations. Detection limits for major and trace elements are 0.002% and 0.05 ppm, respectively.
Table 2. Major and trace element compositions of samples from the Dopolan deposit, Khaneh–Kat and Neyriz Formations. Detection limits for major and trace elements are 0.002% and 0.05 ppm, respectively.
Major Element (wt %)Samples
Do-IR-1Do-IR-2Do-IR-3Do-IR-4Do-Cl-1Do-Cl-2Do-Oo-1Do-Oo-2Do-Oo-3
SiO27.2116.1414.6211.2535.2831.877.445.685.63
Al2O342.0231.3437.5847.147.3950.6968.1167.7868.23
Fe2O319.6821.0816.4211.182.591.023.532.474.55
CaO0.060.100.040.130.060.050.070.110.04
K2O0.511.160.610.850.800.360.300.650.80
MnO0.010.020.010.000.000.000.000.000.00
Na2O0.010.010.010.060.010.010.010.020.01
P2O50.100.090.080.070.060.070.100.070.09
MgO0.280.580.360.420.100.280.050.410.10
TiO21.471.071.751.501.922.382.152.352.35
LOI26.325.928.1326.3211.2712.6217.3520.3616.89
Sum97.6497.4899.6298.8899.4799.3599.1299.8998.69
Trace Element (ppm)Samples
Do-IR-1Do-IR-2Do-IR-3Do-IR-4Do-Cl-1Do-Cl-2Do-Oo-1Do-Oo-2Do-Oo-3
Ni340394345382296289236150111
Cr429286577381359255486442389
Ba122018306268810
Hf6.66.513.69.78.914.812.29.918.9
Th24.525.734.336.221.549.644.528.446.3
Zr246250340.1364271583419308557
Nb43.135.346.238.345.654.452.654.777.7
S>5>5>5>512.11.41.52.5
Sr413342450408423542517567552
Ta4.63.96.22.74.455.35.27.2
Major Element (wt %)Samples
Do-Oo-4Do-Pi-1Do-Pi-2Do-Pi-3Do-Org-1Do-Org-2Khaneh–KatNeyriz
SiO23.204.675.453.1134.8435.441.090.32
Al2O372.8974.9873.2575.0931.126.550.391.42
Fe2O30.922.262.331.365.527.450.744.16
CaO0.030.040.080.070.900.1334.3235.11
K2O1.210.251.640.294.063.830.110.86
MnO0.000.000.000.020.030.000.010.04
Na2O0.070.010.040.060.050.120.030.03
P2O50.080.130.120.150.060.050.020.02
MgO0.240.020.030.340.320.9119.8118.87
TiO22.652.832.342.770.950.940.040.12
LOI17.8215.4215.6716.5622.6723.2443.0539.85
Sum99.11100.62100.9699.82100.5098.6699.59100.79
Trace Element (ppm)Samples
Do-Oo-4Do-Pi-1Do-Pi-2Do-Pi-3Do-Org-1Do-Org-2Khaneh–KatNeyriz
Ni27322025817040727033.225.1
Cr32913213930374710882619
Ba3010-5134637126
Hf17.716.915.517.85.36.20.20.7
Th51.938.638.754.710.617.30.61.7
Zr535.8467.2437.8478.42061325.927.8
Nb67.941.428.462.438.233.83.84.4
S1.71.21.41.22.21.71.51.7
Sr48625418744632534581.651.8
Ta8.15.63.16.43.62.90.20.2
LOI = Loss or Ignition.
The high SiO2 content of the bauxite facies is a result of weak lateritization [8] and the presence of kaolinite [11]. Based on the Al2O3–Fe2O3–SiO2 ternary diagram [50], organic-rich and clay-rich bauxite horizons show weak and moderate lateritization, respectively, whereas oolitic, pisolitic and iron-rich bauxites plot in the strong lateritization field (Figure 6). Furthermore, the Dopolan bauxite samples plot in the bauxite and kaolinite bauxite fields on the Al2O3–Fe2O3–SiO2 ternary diagram (Figure 7) suggesting tropical paleo-geographic conditions which favored bauxitization and the formation of bauxite horizons [9,51].
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Figure 6. Ternary plot of the SiO2–Al2O3–Fe2O3 system (after [50]) showing the intensity of lateritization of the Dopolan bauxites.
Figure 6. Ternary plot of the SiO2–Al2O3–Fe2O3 system (after [50]) showing the intensity of lateritization of the Dopolan bauxites.
Minerals 06 00011 g006
Minerals 06 00011 g007 1024
Figure 7. Ternary plot of the SiO2–Al2O3–Fe2O3–system (after [52]) showing the Dopolan deposit data.
Figure 7. Ternary plot of the SiO2–Al2O3–Fe2O3–system (after [52]) showing the Dopolan deposit data.
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High content of trace elements such as Cr (132–1088 ppm), Zr (132–557 ppm) and Nb (28–77 ppm) is a significant and common feature of the Dopolan bauxite (Table 2). Trace elements such as Cr, Ni, V, Co, Zr are considered bauxitophilic [53] and they are used in geochemical calculations such as mass change and identification of parent rocks. Trace elements such as Zr, V, and Ga are enriched in all parts of the bauxite; these trace elements are low in the Khaneh–Kat Formation. Zr, Hf, Nb and Ta are immobile elements and show positive correlations (R2 = 0.64 to 0.87) with TiO2 (Figure 8).
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Figure 8. Variation diagrams showing correlations between TiO2 and trace elements in the Dopolan bauxite deposit. Red circles are carbonate samples, blue circles are bauxite samples.
Figure 8. Variation diagrams showing correlations between TiO2 and trace elements in the Dopolan bauxite deposit. Red circles are carbonate samples, blue circles are bauxite samples.
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5.2. Rare Earth Elements

The chondrite-normalized REE diagram of the bauxite horizons and argillitic dolomite from the Khaneh–Kat Formation shows a similar pattern with light rare earth element (LREE) enrichment and heavy rare earth element (HREE) depletion and a negative Eu anomaly (Figure 9).
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Figure 9. Chondrite-normalized rare earth element (REE) patterns of the bauxite samples as well as argillitic dolomite from the Khaneh–Kat Formation.
Figure 9. Chondrite-normalized rare earth element (REE) patterns of the bauxite samples as well as argillitic dolomite from the Khaneh–Kat Formation.
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The ∑REE of bauxite samples vary from 480 to 1140 ppm (Table 3). There is also a decreasing trend in ∑REE in the bauxite profile from the pisolitic bauxite (1037 ppm) to the iron-rich bauxite (890 ppm). The organic-rich bauxite contains low ∑REE values (522 ppm) (Table 3).
Table
Table 3. Rare earth element composition of samples from the Dopolan bauxite deposit.
Table 3. Rare earth element composition of samples from the Dopolan bauxite deposit.
Element (ppm)IR-1IR-2IR-3IR-4Cl-1Cl-2Oo-1Oo-2Oo-3Oo-4Pi-1Pi-2Pi-3Org-1Org-2KhaNyCh.
La187.23177.43199.32168.85164.56170.59199.07168.32173.80148.79198.90242.30210.2088.4082.124.184.310.310
Ce489.44479.65386.09389.69367.88376.46434.65347.40456.36343.22428.10532.20480.04287.90209.956.8214.900.808
Pr32.3014.6033.5134.2332.0330.1659.4055.7154.6048.9752.0964.0854.5719.3016.691.093.220.122
Nd122.26131.35119.91114.71123.71109.27148.40156.23144.75159.31146.69161.28150.12108.33105.564.252.800.600
Sm9.258.2910.939.0410.5412.3113.0111.6710.4211.7614.3312.0913.438.678.480.982.850.195
Eu1.731.180.951.531.131.982.283.252.513.353.213.523.441.451.510.240.300.073
Gd4.258.135.837.327.368.3816.2114.7015.3815.6614.3116.1316.717.016.251.103.770.259
Tb1.651.371.842.731.040.872.762.912.812.203.223.253.581.031.130.200.430.047
Dy14.5918.4012.4713.958.6510.9513.4114.3117.4814.3618.6818.2310.858.1213.030.652.620.322
Ho2.982.572.161.211.231.242.292.282.732.813.323.672.211.261.640.250.520.071
Er6.805.146.535.884.324.747.097.087.227.488.998.726.845.745.340.671.370.210
Tm1.471.521.631.640.460.612.511.541.430.922.672.831.840.480.510.090.180.032
Yb10.3610.4011.3711.047.787.3616.3815.6714.2114.3416.7016.3013.106.007.410.611.100.209
Lu1.411.511.621.711.281.151.401.401.602.022.712.931.780.380.470.090.160.032
Y47.1057.2058.1055.3042.7036.2655.2058.6443.1036.0665.1861.2147.4627.3627.406.9713.60-
ΣREE932.82918.74852.26818.83774.67772.33974.06861.11948.40811.25979.101148.741016.17571.43487.4927.1952.134.24
La/Yb18.0717.0617.5315.2921.1523.1812.1510.7412.2310.3811.9114.8716.0514.7311.086.853.921.48
Eu/Eu *0.080.040.040.060.040.060.050.080.060.080.070.080.070.060.060.070.0338.77
Ce/Ce *1.731.681.331.491.381.471.351.141.541.191.341.441.441.571.200.862.291.09
Eu/Eu * = (Eu·n)/√(Sm·n) × (Gd·n). Ce/Ce * = Ce·n/√(La·n) × (Nd·n). Chondrite values are from Boynton, 1984 [54]. Ny = Nyriz Formation, Ch. = Chondrite.
The ∑REE content of the Kaneh–Kat Formation (27 ppm) is within the average range of carbonate rocks (23–27 ppm; [46]. Iron-rich and clay-rich bauxites with the lowest content of ∑REE the carbonate bed rock. Enrichment of LREEs in the bauxitic zone is a result of authigenic processes [13].
The chondrite-normalized REE patterns of different bauxite horizons and Khaneh–Kat Formation show similar patterns with negative Eu anomalies (0.04–0.08; Table 3). All sequences of the bauxites and bedrock (Khaneh–Kat dolomite) display negative Eu anomalies. Eu/Eu * anomalies in all bauxite horizons show that this ratio is conservative. Variations of La/Y ratio in the bauxites have been used for determining change in pH during weathering [11,13,55]; values of La/Y < 1 imply prevalence of acidic conditions whereas values of La/Y > 1 indicate basic conditions (Figure 10). Calculated La/Y variations in bauxites can be related to LREE variations in the bauxite profile suggesting that the leaching of LREE in the pisolitic bauxite may be the result of low pH conditions. Ce/Ce * ratio in the 0.86–1.73 range (Table 3) suggests that Ce+3 was leached out from the oolitic and pisolitc bauxite and was available to be transported to deeper layers and precipitated near the bed rock [15].
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Figure 10. La/Y ratios from the Khaneh–Kat Formation and bauxite samples of the Dopolan deposit [13,55].
Figure 10. La/Y ratios from the Khaneh–Kat Formation and bauxite samples of the Dopolan deposit [13,55].
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5.3. Protolith

The Cr-Ni binary diagram can be used to predict the protolith of the bauxite deposit [2,11,22,56]; Dopolan samples plot in the karst bauxite field (Figure 11). Karst bauxites form on a variety of parent rocks such as carbonates, rock debris, volcanic ash, and wind-born material [22]. To identify the protolith of the Dopolan bauxite, calculated correlation coefficients of major elements are used. The strong positive correlation between Ti and Al in the Dopolan deposit suggests a relationship between the bauxite horizons and the argillitic dolomite of the Khaneh–Kat Formation (Figure 12).
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Figure 11. Binary diagram of Cr versus Ni to imply parent rock (after [2,11,22,56]). The Dopolan data plot in the karst bauxite field. The Khaneh–Kat data plot near the carbonate rocks.
Figure 11. Binary diagram of Cr versus Ni to imply parent rock (after [2,11,22,56]). The Dopolan data plot in the karst bauxite field. The Khaneh–Kat data plot near the carbonate rocks.
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Figure 12. Scatter plot of TiO2 versus Al2O3 in the Dopolan deposit. Red circles are carbonate samples, blue circles are bauxite samples.
Figure 12. Scatter plot of TiO2 versus Al2O3 in the Dopolan deposit. Red circles are carbonate samples, blue circles are bauxite samples.
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5.4. Mass Change

Mass change is associated with enrichment or depletion of elements during bauxitization [2,10,14]. The content of immobile elements in relatively fresh (parent) rock and weathered rocks can be used to calculate mass changes during weathering. In the residual accumulated bauxite ore, elements such as Ti, Zr, Hf, Nb, Ta, Cr and Ni are considered to be relatively immobile. Loss and/or gain in mass of the weathered Dopolan profiles were calculated based on Ti, which is strongly immobile during weathering of bauxite [14]. These calculations are based on Maclean [57] expression: where EF= TiO2protolith/TiO2bauxite (Table 4), RC = % component in altered rock × EF (Table 4); and MC = RC − precursor composition (Table 5).
Table
Table 4. Calculated enrichment factor (EF) and reconstructed compositions (RC, in wt %) of samples from bauxite profiles of the Dopolan deposit.
Table 4. Calculated enrichment factor (EF) and reconstructed compositions (RC, in wt %) of samples from bauxite profiles of the Dopolan deposit.
SamplesDo-IR-1Do-IR-2Do-IR-3Do-IR-4Do-Cl-1Do-Cl-2Do-Oo-1Do-Oo-2Do-Oo-3
EF1.0060.7321.2021.0151.0671.3481.3241.4521.392
SiO210.02030.84217.02215.30037.52027.2717.0484.9274.887
Al2O358.39859.88843.75463.75350.39943.37664.52658.79359.231
Fe2O327.34640.27919.11315.1362.7530.8691.4502.1463.948
K2O0.7032.2110.7161.1510.8460.3080.2850.5640.690
MnO0.0170.0390.0130.0000.0020.0000.0020.0010.001
Na2O0.0190.0260.0160.0810.0140.0120.0130.0170.012
P2O50.1390.1720.0930.0950.0640.0600.0950.0610.078
MgO0.3921.1090.4250.5690.1060.2400.0470.3600.086
TiO22.0402.0402.0402.0302.0402.0402.0402.0402.040
Al2O3 is enriched in the bauxite horizons especially in the pisolitic and oolitic bauxite (Figure 13). Iron enrichment in the iron-rich bauxite is due to the presence of pyrite, whereas all other bauxite horizons show Fe depletion. The highest Si enrichment is seen in the organic-rich bauxite which is related to the Eh–pH conditions and the presence of clay minerals. Ca, K, Na and P2O5 were leached out of weathering protolith whereas Al was enriched in the residual debris.
Table
Table 5. Mass changes (in %) of the Dopolan samples based on the reconstructed compositions (RC, in wt %).
Table 5. Mass changes (in %) of the Dopolan samples based on the reconstructed compositions (RC, in wt %).
SamplesDo-IR-1Do-IR-2Do-IR-3Do-IR-4Do-Cl-1Do-Cl-2Do-Oo-1Do-Oo-2Do-Oo-3Do-Oo-4Do-Pi-1Do-Pi-2Do-Pi-3Do-Org-1Do-Org-2
SiO2−34.47−13.65−27.47−29.19−6.97−17.22−37.44−39.56−39.60−42.03−41.12−39.74−42.2030.2732.65
Al2O342.4843.9727.8447.8334.4827.4648.6142.8743.3140.1938.1347.9439.4450.8241.87
Fe2O3−3.009.93−11.24−15.21−27.60−29.48−28.90−28.21−26.40−29.65−28.72−28.32−29.35−18.51−14.13
K2O−3.72−2.22−3.71−3.28−3.58−4.12−4.14−3.86−3.74−3.50−4.24−3.00−4.214.293.91
MnO−0.53−0.51−0.54−0.55−0.55−0.55−0.55−0.55−0.55−0.55-0.55−0.55−0.53−0.48−0.55
Na2O−1.21−1.20−1.21−1.14−1.21−1.21−1.21−1.21−1.21−1.17−1.21−1.19−1.18−1.11−0.96
P2O5−0.80−0.76−0.84−0.84−0.87−0.88−0.84−0.87−0.86−0.87−0.84−0.83−0.82−0.81−0.83
MgO0.391.110.420.570.110.240.050.360.090.180.010.030.250.681.98
TiO20.000.000.00−0.010.000.000.000.000.000.000.000.000.000.000.01
∑Mc−0.8636.67−16.74−1.82−6.19−25.76−24.43−31.03−28.96−37.38−38.55−25.66−38.6165.1563.95
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Figure 13. Mass changes in the Dopolan bauxite deposit relative to the Khaneh–Kat argillitic dolomite. The mass changes can be considered as enrichment and depletion in weight % or grams per 100 g of the argillic dolomite precursor.
Figure 13. Mass changes in the Dopolan bauxite deposit relative to the Khaneh–Kat argillitic dolomite. The mass changes can be considered as enrichment and depletion in weight % or grams per 100 g of the argillic dolomite precursor.
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5.5. Isotopic Signatures

The geochemical characteristics of O and D isotopes have been widely used to study bauxitization processes and paleo-climate changes (e.g., [58]). Hydroxyl (OH) bearing minerals such as kaolinite and boehmite are considered to be one of the main controls on the isotopic composition of bauxite deposits [28].
Oxygen and hydrogen isotope compositions of the footwall dolomite (Khaneh–Kat Formation) are +28.8‰ and −59.7‰, respectively (Table 6). δ18O and δD values of various bauxite horizons range from +7.63‰ to +9.35‰ and −66.49‰ to −49.91‰, respectively (Table 6 and Figure 14). One sample from the calcite cement of the footwall dolomite shows δ13C value of −7.34‰ (Table 6). Such depleted δ13C values are considered to reflect subaerial exposure and influence of the karstification associated with the unconformity surface [48].
Table
Table 6. Stable isotope composition of selected samples from the Dopolan bauxite deposit.
Table 6. Stable isotope composition of selected samples from the Dopolan bauxite deposit.
Samplesδ18OSMOW (‰)δDSMOW (‰)δ13CPDB (‰)
D-1 (Iron-rich bauxite)8.74−49.91-
D-2 (Clay-rich bauxite)8.37−66.49-
D-3 (Oolitic bauxite)7.63−56.65-
D-4 (Pisolitic bauxite)7.89−54.77-
D-5 (Organic-rich bauxite)9.35−60.59-
D-6 (Khaneh–Kat Formation)28.85−59.69−7.34
PDB = Pee Dee Belemnite.
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Figure 14. Vertical variation of the δ18O and δD values of the Dopolan and the Khaneh–Kat Formation.
Figure 14. Vertical variation of the δ18O and δD values of the Dopolan and the Khaneh–Kat Formation.
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Calcite from the footwall dolomite (Khaneh–Kat Formation) plots away from the kaolinite line (δD = 7.55δ18O − 219); [59]; Figure 15 and Figure 16). The Dopolan bauxite samples plot close to the boehmite line (Figure 15). Homogenous isotopic compositions of these samples indicates a relatively constant isotope composition during the development of bauxite horizons and remobilization of Al (secondary boehmite [30]).
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Figure 15. Isotope composition of bauxite horizons of the Dopolan deposit. Kaolinite line after [59]; boehmite line after [29]. MWL, Meteoric water line. SMOW, Standard mean ocean water.
Figure 15. Isotope composition of bauxite horizons of the Dopolan deposit. Kaolinite line after [59]; boehmite line after [29]. MWL, Meteoric water line. SMOW, Standard mean ocean water.
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Figure 16. δ18O and δD values of the Dopolan kaolinite compared with data from Amazonia (after [60]), Yaou (after [58]) and Dehdasht after [27]. Kaolinite line (after [59]). SMOW = Standard Mean Ocean Water; S/H = supergene/hypogene line after [61].
Figure 16. δ18O and δD values of the Dopolan kaolinite compared with data from Amazonia (after [60]), Yaou (after [58]) and Dehdasht after [27]. Kaolinite line (after [59]). SMOW = Standard Mean Ocean Water; S/H = supergene/hypogene line after [61].
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6. Discussion

In karstic terranes, soluble bedrocks such as limestone and dolomite are dissolved by CO2-enriched water. Karstification creates space for bauxite deposition. Bauxite accumulated in the karst cavities is more protected from erosion compared to regolith on silicate rocks [11,62]. Such a process leads to the formation of a specific type of karst called ore karst which occurs only on the exokarst floor [63]. The term was used in carbonate rocks wherein the ore was developed due to dissolution of carbonates by acidic fluids related to oxidation of sulfide ores [63]. Mineralogy, karst characteristics, wall–rock relationship, and geological setting indicate that the Triassic Dopolan bauxite deposit formed in a karstic environment. Boehmite, diaspore, kaolinite, nacrite, pyrite, anatase and rutile are common minerals. The matrix type suggests an authigenic origin for bauxite; however, terrigenous grains such as intraclasts, ooids and erosional ooid nucleus imply a semi-authigenic origin, at least for part of the deposit. Also, the presence of angular bauxite and detrital phases indicates some displacement into or within the karstic area. Gibbsite can transform to boehmite in surface environments and boehmite can transform to diaspore in a near-surface environment [18,64,65,66,67]. Kaolinite and other clays such as nacrite can also be present in bauxite deposits [53]. The pisolitic texture results from aggregation of discolored pisolites showing evidence of deferrification process. Deferrification in pisolitic bauxites may be controlled by organic ligands which affect the solubility and dissolution of iron oxides [7]. Micro-organisms can also reduce Fe3+ to Fe2+ in solutions to provide energy for metabolism potentially leading to deferrification [68]. The organic ligands could have also contributed to the formation of acidic (pH between 3 and 6) and reducing conditions which prevailed during bauxitization in the Dopolan area.
Trace element composition (e.g., Cr, Ni; Figure 11) show that the Dopolan deposit is a karst bauxite type which located in the Zagros Fold-Thrust Zone. The Zagros fold-thrust belt contains the most important sedimentary basins in Iran, wherein sedimentary rocks reach depths of more than 12 km and are comprised mainly of carbonate and detrital sediments. The lack of magmatic units suggests that the Khaneh–Kat argillic dolomite can be considered as the likely parent rock for the Dopolan bauxite deposit. The similarity of REE pattern of bauxite horizons and the Khaneh–Kat argillic dolomite support that the Khaneh–Kat could be parent rock of the Dopolan bauxite [69]. Furthermore, the REEs show affinity to mobilization during bauxitization and subsequent redistribution [15]. The REE patterns demonstrate that bauxite samples are enriched in REEs, possibly due to prolonged tropical weathering which led to the breakdown of rock-forming minerals [70,71].
Minor REE variations across the bauxite horizons probably reflect Eh and pH fluctuations during formation of each horizon [72]. Mobility of LREEs depends on pH variation in the bauxite profile in the weathering system. Variations of La/Y ratio in bauxite have been used to study pH change during weathering [11,13]; values of La/Y < 1 imply prevalence of acidic conditions whereas values of La/Y > 1 indicate basic conditions (Figure 10). Iron-rich, clay-rich, oolitic, and organic-rich bauxite horizons of Dopolan are enriched in LREEs suggesting high pH conditions during formation of these bauxites (Figure 10). However, the pisolitic bauxite is depleted in LREEs possibly reflecting low pH conditions during formation (Figure 10). The acidic solutions probably resulted from weathering of pyrite which explains HREEs’ enrichment in the pisolitic bauxite [73].
Positive correlation between REEs and some major elements implies that the REEs are hosted in the specific minerals (Table 7) or both REEs, and major elements have been enriched by the same processes. In the Dopolan deposit, Ti has positive correlation with all REEs (Table 7) which probably suggests that distribution of REE is controlled by the formation of authigenic heavy minerals such as rutile and anatase [74]. The strong positive correlations (R = 0.71–0.80) between HREEs and Al2O3 suggest (Table 7) that they may be hosted by Al oxides (e.g., diaspore and boehmite minerals) or their relative content increased during bauxite formation processes.
In addition, variation in the amount of pyrite, organic matter and other minerals such as oxyhydroxides, phosphates and Fe oxides in the weathering profile can affect Eh–pH conditions under wet-tropical environments [7,13,75,76]. The mass change calculations of the bauxite horizons show that Ca, K and P2O5 were largely leached out of the weathering system whereas Al was enriched in the residual system. The bauxitization at Dopolan occurred along a karstification surface between the Khaneh–Kat and Neyriz Formations. Due to high CO2 and temperature [77], continental weathering was intense during this time period. The depleted δ13C value (−7.34‰) supports this hypothesis that the Khaneh–Kat Formation has experienced post-depositional isotope exchange with meteoric waters during the karstification process. Similar to the Early Permian Australian bauxite deposits, the oxygen and hydrogen isotopic compositions of the Dopolan bauxite fall close to the boehmite line (Figure 15 and Figure 17). The Dopolan kaolinite plots on the left of the kaolinite line and the supergene/hypogene line (S/H; Figure 17) indicating kaolinite equilibrium with meteoric water and supports the supergene origin for kaolinite. Furthermore, the isotopic composition of kaolinite (Figure 16) shows that the deposit formed under a warm climate. This climate is consistent with the results of Wang et al. [41] who, based on the carbon-isotope compositions of calcite in the Khaneh–Kat Formation, inferred a warm climate during Permo–Triassic time.
Table
Table 7. Correlation coefficients of REEs and some major and trace elements of the Dopolan bauxite deposit.
Table 7. Correlation coefficients of REEs and some major and trace elements of the Dopolan bauxite deposit.
Element/Oxide Al2O3Fe2O3TiO2P2O5ZrNbHfTh
La0.830.180.820.850.770.640.770.79
Ce0.830.280.750.850.730.660.710.74
Pr0.82−0.280.900.770.790.700.840.80
Nd0.900.040.860.770.770.790.780.77
Sm0.91−0.120.930.790.840.760.850.84
Eu0.92−0.370.870.760.750.640.800.75
Gd0.92−0.410.840.720.770.680.810.78
Tb0.87−0.130.780.830.680.570.760.73
Dy0.710.300.660.690.640.560.650.63
Ho0.750.180.680.800.600.500.670.60
Er0.880.040.820.810.730.660.780.72
Tm0.720.100.640.830.550.320.610.60
Yb0.92−0.020.850.800.750.670.790.77
Lu0.82−0.000.800.810.730.460.790.73
Y0.720.290.690.750.590.470.600.613
Such paleo-climatic conditions in this part of the High Zagros Mountain favored bauxitization, causing mobilization and enrichment of aluminum. Geochemical composition, stratigraphic evidence, and texture/mineralogy show that dolomite from the Khaneh–Kat Formation was protolith for the bauxite deposit at Dopolan. The REE pattern of the Dopolan bauxite horizons reflects enrichment in LREE in the bauxite zone of an authigenic origin. Enrichment and depletion of elements were strongly influenced by the pH of solution; low pH favored leaching and high pH favored enrichment of elements in the bauxite horizons.
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Figure 17. Relationship between δ18O and δD values for clay minerals from Australian regolith profiles (Data from [78] and the Dopolan kaolinite. SMOW, Standard mean ocean water; S/H = supergen/hypogene kaolinite line from [61]; Kaolinite line from [59].
Figure 17. Relationship between δ18O and δD values for clay minerals from Australian regolith profiles (Data from [78] and the Dopolan kaolinite. SMOW, Standard mean ocean water; S/H = supergen/hypogene kaolinite line from [61]; Kaolinite line from [59].
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7. Conclusions

The following conclusions can be made based on the data obtained from the Dopolan deposit.
1. Field observation and geochemical data suggest that the Dopolan bauxite deposit (in the Zagros sedimentary basin) is a karst bauxite type and originated from the argillitic dolomite of the Khaneh–Kat Formation.
The main mineral assemblage of this deposit consists of diaspore, boehmite, and kaolinite. Oolitic, pisolitic, pelitomorphic, microcrystalline and microgranular are the most important textures. These textures suggest an authigenic origin for the deposit. However, the presence of angular bauxite, detrital phases, pelitomorphic and fluidal textures indicates some small displacement into or within the karstic area.
2. Mass change calculation shows silica dissolution and deferrification in the bauxite horizons, causing Al-enrichment and bauxite formation.
3. The chondrite-normalized REE patterns of the different bauxite horizons and the Khaneh–Kat dolomite are similar, which may suggest that the Khaneh–Kat dolomite is the parent rock. The REEs are most enriched in the pisolitic and oolitic bauxite which is located in the upper part of the bauxite horizon and lie within the strong laterization. Minor REE changes across the bauxite profile probably reflect Eh and pH variations in the bauxitic profile.
4. The Dopolan deposit shows a relatively constant isotopic condition during the development of bauxite horizons and remobilization of Al. The δ18O and δD values of kaolinite samples suggest kaolinite equilibrium with meteoric water which supports a supergene origin.
5. The δ13C value (−7.34‰) of Khaneh–Kat formation is lower than the values of normal Triassic carbonates (−1‰–+5‰): thus supporting that the Khaneh–Kat Formation experienced post-depositional isotope exchange with organic carbon by meteoric water during karstification processes.

Acknowledgments

All financial support for this research was provided by the Research Office at Shiraz University, Iran. We thank all staff of this office for their support. The CEO of the Dopolan bauxite mine is thanked for providing unlimited access to the Dopolan deposit. Mohammad Ali Mackizadeh (Isfahan University), Mostafa Nejadhadad (Shiraz University), and Maryam Khodadadi (Shiraz University) are thanked for their help during field work. The authors are also grateful to the anonymous reviewers of the journal of Minerals for their constructive comments.

Conflicts of Interest

The authors declare no conflict of interest.

References

  1. Dill, H. The “chessboard” classification scheme of mineral deposits: Mineralogy and geology from aluminum to zirconium. Earth Sci. Rev. 2010, 100, 1–420. [Google Scholar] [CrossRef]
  2. Valeton, I.; Biermann, M.; Reche, R.; Rosenberg, F. Genesi of nickel laterites and bauxite, Antalya, Turkey. J. Asian Earth Sci. 1987, 27, 512–522. [Google Scholar]
  3. Petrascheck, W.E. The genesis of allochthonous karst type bauxite deposits of Southern Europe. Miner. Depos. 1989, 24, 77–82. [Google Scholar] [CrossRef]
  4. Yaalon, D.H. Soils in the Mediterranean region; what makes them different? Catena 1997, 28, 157–169. [Google Scholar] [CrossRef]
  5. Oggiano, G.; Mameli, P. The bauxite of North Western Sardinia. Rend. Semin. Fac. Sci. Univ. Cagliari Suppl. 2001, 71, 59–73. [Google Scholar]
  6. Ji, H.; Wang, S.; Ouyang, Z.; Zhang, S.; Sun, C.; Liu, X.; Zhou, D. Geochemistry of red residua underlying dolomites in karst terrains of Yunnan–Guizhou Plateau. II. The mobility of rare earth elements during weathering. Chem. Geol. 2004, 203, 1–27. [Google Scholar] [CrossRef]
  7. Laskou, M.; Economou-Eliopoulos, M. The role of microorganisms on the mineralogical and geochemical characteristics of the Parnassos-Ghiona bauxite deposits, Greece. J. Geochem. Explor. 2007, 93, 67–77. [Google Scholar] [CrossRef]
  8. Mameli, P.; Mongelli, G.; Oggiano, G.; Dinelli, E. Geological, geochemical and mineralogical features of some bauxite deposits from Nurra (Western Sardinia, Italy): Insights on conditions of formation and parental affinity. Int. J. Earth Sci. 2007, 96, 887–902. [Google Scholar] [CrossRef]
  9. Zarasvandi, A.; Charchi, A.; Carranza, E.J.M.; Alizadeh, B. Karst bauxite deposits in the Zagros mountain belt, Iran. Ore Geol. Rev. 2008, 34, 521–532. [Google Scholar] [CrossRef]
  10. Zarasvandi, A.; Zamanian, H.; Hejazi, E. Immobile elements and mass changes geochemistry at Sar-Faryab bauxite deposit, Zagros Mountains, Iran. J. Geochem. Explor. 2010, 107, 77–85. [Google Scholar] [CrossRef]
  11. Zarasvandi, A.; Carranza, E.J.M.; Ellahi, S.S. Geological, geochemical, and mineralogical characteristics of the Mandan and Deh-now bauxite deposits, Zagros Fold Belt, Iran. Ore Geol. Rev. 2012, 48, 125–138. [Google Scholar] [CrossRef]
  12. Bardossy, G. European Bauxite Deposits. In Bauxite: Proceedings 1984 Bauxite Sympo-Sium; Leonard, J., Jr., Ed.; Society of Mining Engineers: New York, NY, USA, 1984; pp. 411–435. [Google Scholar]
  13. Maksimovic, Z.; Panto, G. Contribution to the geochemistry of the rare earth elements in the karst-bauxite deposits of Yugoslavia and Greece. Geoderma 1991, 51, 93–109. [Google Scholar] [CrossRef]
  14. Maclean, W.H.; Bonavia, F.F.; Sanna, G. Argillite debris converted to bauxite during karst weathering: Evidence from immobile element geochemistry at the Olmedo Deposit, Sardinia. Miner. Depos. 1997, 32, 607–616. [Google Scholar] [CrossRef]
  15. Muzaffer, M.; Kupeli, S.; Aryk, F.; Ayhan, A.; Zedef, V.; Doyen, A. Rare earth element (REE) geochemistry and genetic implications of the Mortaş bauxite deposit (Seydişehir/Konya–Southern Turkey). Chem. Erde Geochem. 2009, 69, 143–159. [Google Scholar] [CrossRef]
  16. Boni, M.; Reddy, S.M.; Mondillo, N.; Balassone, G.; Taylor, R. A distant magmatic source for Cretaceous karst bauxites of southern Apennines (Italy), revealed through SHRIMP zircon age dating. Terra Nova 2012, 24, 326–332. [Google Scholar] [CrossRef]
  17. Mongelli, G.; Boni, M.; Buccione, R.; Sinisi, R. Geochemistry of the Apulian karst bauxites (Southern Italy): Chemical fractionation and parental affinities. Ore Geol. Rev. 2014, 63, 9–21. [Google Scholar] [CrossRef]
  18. Bardossy, G. Karst Bauxites: Bauxite Deposits on Carbonate Rocks (Developments in Economic Geology); Elsevier: Amsterdam, The Netherlands, 1982. [Google Scholar]
  19. Wang, Q.; Liu, X.; Yan, C. Mineralogical and geochemical studies of boron-rich bauxite ore deposits in the Songqi region, SW Henan, China. Ore Geol. Rev. 2012, 48, 258–270. [Google Scholar] [CrossRef]
  20. Franceschelli, M.; Puxeddu, M.; Memmi, I. Li, B-rich Rhaetian metabauxite, Tuscany, Italy: Reworking of older bauxites and igneous rocks. Chem. Geol. 1998, 144, 221–242. [Google Scholar] [CrossRef]
  21. Calagari, A.A.; Abedini, A. Geochemical investigations on Permo-Triassic bauxitehorizon at Kanisheeteh, east of Bukan, West-Azarbaijan, Iran. J. Geochem. Explor. 2007, 94, 1–18. [Google Scholar] [CrossRef]
  22. Liu, X.; Wang, Q.; Deng, J.; Zhang, Q.; Sun, S.; Meng, J. Mineralogical and geochemical investigations of the Dajia Salento-type bauxite deposits, western Guangxi, China. J. Geochem. Explor. 2010, 105, 137–152. [Google Scholar] [CrossRef]
  23. Maclean, W.H.; Kranidiotis, P. Immobile elements as monitors of mass transfer in hydrothermal alteration: Phelps dodge massive sulfide deposits, Matagami, Quebec. Econ. Geol. 1987, 2, 951–962. [Google Scholar] [CrossRef]
  24. Valeton, I.; Schumann, A.; Vinc, R.; Wieneke, M. Supergene alteration since the Upper Cretaceous on alkaline igneous and metasomatic rocks of the Pososde Caldas ring complex, Minas Gerais, Brazil. Appl. Geochem. 1997, 12, 133–154. [Google Scholar] [CrossRef]
  25. Liaghat, S.; Hosseini, M.; Zarasvandi, A. Determination of the origin and mass change geochemistry during bauxitization process at the Hangam deposit, SW Iran. Geochem. J. 2003, 37, 627–637. [Google Scholar] [CrossRef]
  26. Bogatyrev, B.A.; Zhukov, V.V. Bauxite provinces of the world. Geol. Ore Depos. 2009, 5, 339–355. [Google Scholar] [CrossRef]
  27. Hoefs, J. Stable Isotope Geochemistry, 6th ed.; Springer-Verlag: Berlin, Germany, 2009; p. 285. [Google Scholar]
  28. Chivas, A.R.; Bird, M.I. Palaeoclimate from Gondwana clays. In Clays: Controlling the Environment, Proceeding of the 10th International Clay Conference, Adelaide, Australia, 18–23 July 1993; Churchmann, G.J., Fitzpatrick, R.W., Eggleton, R.A., Eds.; CSIRO Pub: Melbourne, Australia; pp. 333–338.
  29. Bird, M.I.; Chivas, A.R. Stable-isotope geochronology of the Australian Regolith. Geochim. Cosmochim. Acta 1989, 53, 3239–3256. [Google Scholar] [CrossRef]
  30. Zarasvandi, A.; Foroghinia, A.; Pourkaseb, H.; Charchi, A. Stable isotopes geochemistry of the bauxite horizons in the Dehdasht area, Southwest Iran. Iran. J. Sci. Technol. 2013, 37, 189–197. [Google Scholar]
  31. Smaeli, D.; Rahimpour-Bonab, H.; Esna-Ashari, A.; Kananian, A. Petrography and geochemistry of the Jajarm karst bauxite ore deposit, NE Iran: Implications for source rock material and ore genesis. Turk. J. Earth Sci. 2010, 19, 1–17. [Google Scholar]
  32. Ehsanbakhash, M. Investigation of the Dopolan Bauxite Deposit. Master’s Thesis, Shahid Beheshti University, Tehran, Iran, 1993. [Google Scholar]
  33. Khodadadi, M.; Taghipour, B. Mineralogy, Geochemistry and Genesis of Dopolan Bauxite Deposit, ChaharMahal and Bakhtiari. Master’s Thesis, Shiraz University, Shiraz, Iran, 2014. [Google Scholar]
  34. Agard, P.; Omrani, J.; Jolivet, L.; Mouthereau, F. Convergence history across Zagros, Iran; constraints from collisional and earlier deformation. Int. J. Earth Sci. 2005, 94, 401–419. [Google Scholar] [CrossRef]
  35. Berberian, M.; King, G.C.P. Towards a paleogeography and tectonic evolution of Iran. Can. J. Earth Sci. 1981, 18, 210–265. [Google Scholar] [CrossRef]
  36. Allen, M.; Jackson, J.; Walker, R. Late Cenozoic reorganization of the Arabia–Eurasia collision and the comparison of short-term and long-term deformation rates. Tectonics 2004, 23. [Google Scholar] [CrossRef]
  37. Egard, P.; Omrani, J.; Jolivet, L.; Whitechurch, H.; Vrielynck, B.; Spakman, W.; Monie, P.; Meyer, B.; Wortel, R. Zagros orogeny: A subduction-dominated process. Geol. Mag. 2011, 148, 692–725. [Google Scholar] [CrossRef]
  38. Molnar, M. Tertiary Development of the Zagros Mountains. Available online: http://people.uwec.edu/jolhm/Student_Research/Molnar/reports/zagros.pdf (accessed on 29 January 2016).
  39. Ricou, L.E.; Braud, J.; Brunn, J.H. Le Zagros. Mem. h. ser. Soc. Geol. Fr. 1977, 8, 33–52. (In French) [Google Scholar]
  40. Ehsanbakhshe, M.H.; Rahimzadeh, F. Ardal Map 1; 100000; Geological Survey and Mineral Exploration: Tehran, Iran, 1996.
  41. Wang, W.; Kanob, A.; Okumura, T.; Ma, Y.; Matsumoto, R.; Matsuda, N.; Ueno, K.; Chen, X.; Kakuwad, Y.; Gharaied, M.H.M.; et al. Isotopic chemostratigraphy of the microbialite-bearing Permian–Triassic boundary section in the Zagros Mountains, Iran. Chem. Geol. 2007, 244, 708–714. [Google Scholar] [CrossRef]
  42. Motiei, H. Stratigraphy of Zagros. Geol. Surv. Iran 1993, 1, 60–151. [Google Scholar]
  43. White, W.B.; White, E.L. Karst Landforms: Scope and Processes in the Early Twenty First Century; Elsevier: Amsterdam, The Netherlands, 2013. [Google Scholar]
  44. Parkhiede, H. Exploration Report North Ridge Argillite ore Bauxite Dopolan; Institute of Non-Metallic Materials Esfahan: Isfahan, Iran, 1996. (In Farsi) [Google Scholar]
  45. Bird, M.I.; Longstaffe, F.; Fyfe, W.; Bildgen, P. Oxygen-isotope systematics in a multiphase weathering system in Haiti. Geochim. Cosmochim. Acta 1992, 56, 2831–2838. [Google Scholar] [CrossRef]
  46. Faure, G. Principles of Isotope Geology, 2nd ed.; Wiley: Hoboken, NJ, USA, 1986. [Google Scholar]
  47. German-Heins, J. Iron-rich encrustation on the footwall of the Gant bauxite (Vertes Hills, Hungary) evidence for preservation of organic matter under exceptional conditions? Sediment. Geol. 1994, 94, 73–83. [Google Scholar] [CrossRef]
  48. Hajikazemi, E.; Al-Aasm, S.; Coniglio, M. Subaerial exposure and meteoricdiagenesisof the Cenomanian–Turonian Upper Sarvak formation, Southwestern Iran. Geol. Soc. Lond. 2010, 330, 253–272. [Google Scholar] [CrossRef]
  49. Delvigne, J.E. Atlas of Micromorphology of Mineral Alteration and Weathering; Mineralogical Association of Canada: Quebec, QC, Canada, 1998; p. 494. [Google Scholar]
  50. Schellmann, W. A new definition of laterite. Mem. Geol. Survey India 1986, 120, 1–7. [Google Scholar]
  51. Alavi, M. Regional stratigraphy of the Zagros fold-thrust belt of Iran and its proforeland evolution. Am. J. Sci. 2004, 304, 1–20. [Google Scholar] [CrossRef]
  52. Aleva, G.J.J. Laterites: Concepts, Geology, Morphology and Chemistry; International Soil Reference and Information Centre (ISRIC): Wageningen, The Netherlands, 1994; Volume 169. [Google Scholar]
  53. Boni, M.; Rollinson, G.; Mondillo, N.; Balassone, G.; Santoro, L. Quantitative mineralogical characterization of karst bauxite deposits in the Southern Apennines, Italy. Econ. Geol. 2013, 108, 813–833. [Google Scholar] [CrossRef]
  54. Boynton, W.V. Geochemistry of the rare earth elements: Meteorite studies. In Rare Earth Element Geochemistry; Henderson, P., Ed.; Elsevier: Amsterdam, The Netherlands, 1984; pp. 63–114. [Google Scholar]
  55. Crnicki, J.; Jurkovic, I. Rare earth elements in Triassic bauxites of Croatia Yugoslavia. Travaux 1990, 19, 239–248. [Google Scholar]
  56. Schroll, E.; Sauer, D. Beitrag zur Geochemie von titan, chrom, nikel, cobalt, vanadium und molibdan in bauxitischen gestermenund problem der stofflichen herkunft des aluminiums. Travaux ICSOBA 1968, 5, 83–96. [Google Scholar]
  57. Maclean, W.H. Mass change calculation in altered rock series. Miner. Depos. 1990, 25, 44–49. [Google Scholar] [CrossRef]
  58. Girard, J.P.; Freyssinet, P.; Chazotu, G. Unraveling climatic changes from intraprofile variation in oxygen and hydrogen isotopic composition of goethite and kaolinite in laterites: An integrated study from Yaou, French Guiana. Geochim. Cosmochim. Acta 2000, 64, 409–426. [Google Scholar] [CrossRef]
  59. Savin, S.M.; Epstein, S. The oxygen and hydrogen isotope geochemistry of clay minerals. Geochim. Cosmochim. Acta 1970, 34, 25–42. [Google Scholar] [CrossRef]
  60. Horbe, A.M.C. Oxygen and hydrogen isotopes in pedogenic minerals—Implications for paleoclimate evolution in Amazonia during the Cenozoic. Geoderma 2011, 163, 178–184. [Google Scholar] [CrossRef]
  61. Sheppard, S.M.F.; Gilg, H.A. Stable isotope geochemistry of clay minerals. Clay Miner. 1996, 31, 1–24. [Google Scholar] [CrossRef]
  62. Laznika, P. Giant Metallic Deposits, Future Sources of Industrial Metals; Springer: Berlin/Heidelbery, Germany; New York, NY, USA, 2006. [Google Scholar]
  63. Andreychouk, V.; Dublyansky, Y.; Ezhov, Y.; Lysenin, G. Karst in the Earth’s Crust: Its Distribution and Principal Type; University of Silesia: Sosnowiec, Poland, 2009. [Google Scholar]
  64. Ervin, J.S.; Osborn, E.F. The system Al2O3–H2O. J. Geol. 1951, 59, 381–394. [Google Scholar]
  65. Valeton, I. Bauxite; Elsevier: Amsterdam, The Netherlands, 1972; p. 226. [Google Scholar]
  66. Ozlu, N. The trace elements content of karst bauxite and their parent rocks in the Mediterranean belt. Miner. Depos. 1983, 18, 469–476. [Google Scholar] [CrossRef]
  67. D’Argenio, B.; Mindszenty, A. Bauxites and related paleokarst: Tectonic and climatic event markers at regional unconformities. Eclogae Geol. Helv. 1995, 88, 453–499. [Google Scholar]
  68. Baskar, S.; Baskar, R.; Kaushik, A. Role of microorganism’s in weathering of the Konkan–Goa laterite formation. Curr. Sci. 2003, 85, 1129–1134. [Google Scholar]
  69. Liu, X.; Wang, Q.; Feng, Y.; Li, Z.; Cai, S. Genesis of the Guangou karstic bauxite deposit in western Henan. Ore Geol. Rev. 2013, 55, 162–175. [Google Scholar] [CrossRef]
  70. Price, R.G.; Grayc, M.; Wilson, R.E.; Frey, F.A.; Taylor, S.R. The effects of weathering on rare earth elements Y and Ba abundances in Tertiary basalts from southern Australia. Chem. Geol. 1991, 93, 254–265. [Google Scholar] [CrossRef]
  71. Boulange, B.; Colin, F. Rare earth element mobility during conversion of nepheline syenite into lateritic bauxite at Passa Quatro, Minais Gerais, Brazil. Appl. Geochem. 1994, 9, 701–711. [Google Scholar] [CrossRef]
  72. Compton, S.J.; White, A.R.; Smith, M. Rare earth element behavior soils and salt pan sediments of a semi-arid granitic terrain in the western Cape, South Africa. Chem. Geol. 2003, 201, 239–225. [Google Scholar] [CrossRef]
  73. Mucke, A.; Badejoko, T.A.; Akande, S.O. Petrographic-microchemical studies and origin of the Agbaja Phanerozoic Ironstone Formation, Nupe Basin, Nigeria: A product of ferruginized ooidal kaolin precursor not identical to the Minette-type. Miner. Depos. 1999, 34, 284–296. [Google Scholar]
  74. Koeppenkastrop, D.; de Carlo, E.H. Uptake of rare earth elements from solution by metal oxides. Environ Sci. Technol. 1993, 27, 1796–1802. [Google Scholar] [CrossRef]
  75. Meshram, R.; Randive, K.R. Geochemical study of laterites of the Jamnagar district, Gujarat, India: Implications on parent rock, mineralogy and tectonics. J. Asian Earth Sci. 2011, 42, 1271–1287. [Google Scholar] [CrossRef]
  76. Gonzalez Lopez, J.M.; Bauluz, B.; Fernández-Nieto, C.; Oliete, A.Y. Factors controlling the trace-elements distribution in fine-grained rocks: The Albian kaolinite-rich deposits of the Oliete Basin (NE Spain). Chem. Geol. 2005, 214, 1–19. [Google Scholar] [CrossRef]
  77. Wignall, P.B. Large igneous provinces and mass extinctions. Earth Sci. Rev. 2001, 53, 1–33. [Google Scholar] [CrossRef]
  78. Pillans, B. Geochronology of the Australian Regolith. Available online: http://crcleme.org.au/RegLandEvol/Geochron_of_%20Aust_Regolith.pdf (accessed on 29 January 2016).

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Ellahi, S.S.; Taghipour, B.; Zarasvandi, A.; Bird, M.I.; Somarin, A.K. Mineralogy, Geochemistry and Stable Isotope Studies of the Dopolan Bauxite Deposit, Zagros Mountain, Iran. Minerals 2016, 6, 11. https://doi.org/10.3390/min6010011

AMA Style

Ellahi SS, Taghipour B, Zarasvandi A, Bird MI, Somarin AK. Mineralogy, Geochemistry and Stable Isotope Studies of the Dopolan Bauxite Deposit, Zagros Mountain, Iran. Minerals. 2016; 6(1):11. https://doi.org/10.3390/min6010011

Chicago/Turabian Style

Ellahi, Somayeh Salamab, Batoul Taghipour, Alireza Zarasvandi, Michael I. Bird, and Alireza K. Somarin. 2016. "Mineralogy, Geochemistry and Stable Isotope Studies of the Dopolan Bauxite Deposit, Zagros Mountain, Iran" Minerals 6, no. 1: 11. https://doi.org/10.3390/min6010011

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