Hydrothermal listvenitization and associated mineralizations in Zagros Ophiolites: Implications for mineral exploration in Iraqi Kurdistan

Journal Pre-proof Hydrothermal listvenitization and associated mineralizations in Zagros Ophiolites: Implications for mineral exploration in Iraqi Kurdistan

Mohammad Pirouei, Kamal Kolo, Stavros P. Kalaitzidis PII:

S0375-6742(19)30366-8

DOI:

https://doi.org/10.1016/j.gexplo.2019.106404

Reference:

GEXPLO 106404

To appear in:

Journal of Geochemical Exploration

Received date:

2 July 2019

Revised date:

26 August 2019

Accepted date:

21 October 2019

Please cite this article as: M. Pirouei, K. Kolo and S.P. Kalaitzidis, Hydrothermal listvenitization and associated mineralizations in Zagros Ophiolites: Implications for mineral exploration in Iraqi Kurdistan, Journal of Geochemical Exploration (2019), https://doi.org/10.1016/j.gexplo.2019.106404

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© 2019 Published by Elsevier.

Journal Pre-proof Hydrothermal listvenitization and associated mineralizations in Zagros Ophiolites: implications for mineral exploration in Iraqi Kurdistan

Mohammad Pirouei,*ab Kamal Kolo,a Stavros P. Kalaitzidisc

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: Scientific Research Center, Soran University, PO Box 624, Soran, KRG, Iraq. E-mail:

: Department of Petroleum Geosciences, Faculty of Sciences, Soran University, PO Box 624,

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b

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[email protected]; Tel: +9647508268224.

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Soran, KRG, Iraq.

: Section of Earth Materials, Department of Geology, University of Patras, 265 04 Patras,

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Greece.

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ABSTRACT

A recent geological field work in the Northeastern part of Iraqi Kurdistan and subsequent

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analytical studies showed that the previously reported metamorphosed limestone outcrops around

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Rayat area represent actually listvenite bodies. Field mapping and remote sensing applications were used to understand the spatial distribution of the listvenite; additionally petrographical mineralogical and geochemical studies were applied in order to define the features of the listvenite and to provide an initial genetic model, as well as to assess potential mineralizations related to the listvenitization. Listvenitization occurred as a product of hydrothermal alteration of the Cr-rich serpentinised peridotite that extensively occurs in the area, and resulted in the formation of silica and carbonate listvenites, as well as transitional phases, with fuchsite mineralization being predominant along

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Journal Pre-proof the sheared zones. The results of this study upgrade the broad area of Rayat as potential hydrothermal ore-forming system and provide a basis for future detail prospecting of the area.

Keywords: Hydrothermal alteration; Fuchsite; Listvenite, Rayat, Serpentinites.

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1. INTRODUCTION

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Rose (1837) used for the first time the term listvenite for a silica carbonate rock of Mechnikovsk

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hydrothermal field in the Southern Ural area. In some countries such as Canada, America and Australia, the term "silica-carbonate" is used instead of listvenite. The terms "listvenite" and

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"silica-carbonate" are synonymous and encompass all forms of carbonization from the carbonate-

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rich to silica-rich phases (Buckman and Ashley, 2010).

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Listvenite is composed of Mg-bearing carbonates (i.e. magnesite, ankerite, and dolomite), quartz, fuchsite and various opaque mineral phases. They form during hydrothermal alteration of mafic

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and ultramafic rocks, mostly of peridotite and serpentinised peridotite, by fluids mostly rich in

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CO2 that is accompanied by potassium, sulfur and occasionally gold (Spiridonov, 1991; Hall and Zhao, 1995). Listvenites occur in shear zones, developed in ophiolitic suites, since the shearing provides the required pathways for hydrothermal solutions to circulate (Uçurum, 2000; Çolakoglu, 2009; Zoheir and Lehmann, 2011; Aftabi and Zarrinkoub, 2013). Initially the importance of listvenites was related to the association with gold mineralizations, (Rose, 1837; Aydal, 2014), however recently their significance is increased as potential carbon storage systems, due to the fast kinetics of carbonation reactions in serpentinised peridotites (Hansen et al., 2005; Kelemen et al., 2011; Beinlich et al., 2012; van Noort et al., 2013).

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Journal Pre-proof Numerous listvenites and listvenite-like metasomatites have been studied along the Alpine belts (e.g. Spiridonov, 1991; Auclair and Gauthier, 1993; Hall and Zhao, 1995). Also in the neighborhood of Iraq, listvenites have been described in Turkey (e.g. Uçurum, 2000; Ece et al., 2005; Akbulut et al., 2006) and in Iran (Aftabi and Zarrinkoub, 2013; Ahankoub and Mackizadeh, 2019). However, no previous occurrence of listvenite in Iraqi part of the Zagros Ophiolites has been reported.

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In this paper, a largely unknown listvenite occurrence in Rayat area, NE Iraqi Kurdistan, is

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described by means of geological setting, petrographical and geochemical features. The aim is to

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create a base conceptual model of the listvenitization process in the area, as a future exploration tool for identifying potential mineralization in the broader area of NE Iraqi Kurdistan.

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Additionally as the study area is mountainous with no adequate accessing network, but also land-

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mines, as relics of the past decade’s wars, the listvenites are scattered across the area, and

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Remote sensing (RS) techniques were applied in order to have a comprehensive understanding of their lateral distribution. Remote sensing application to geological mapping and hydrothermal

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alteration and associated minerals is a valuable technique specially for mapping hydrothermally

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altered minerals that have distinct absorption features (Hunt, 1977). Several researchers (Crosta and Moore, 1989; Loughlin, 1991; Abdelsalam et al., 2000; Rokos et al., 2000; Crósta et al., 2003; Zhang etal., 2007; Gabr et al., 2010; Rajendran et al., 2012; Zoheir and Emam, 2014; Othman and Gloaguen, 2017) have used Multispectral remote sensing sensors for mapping of different rocks and minerals.

2. GEOLOGICAL SETTING

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Journal Pre-proof The study area is situated in the northeastern corner of Iraq close to Rayat village and in the proximity of the Iraqi-Iranian Border (Fig. 1). Geotectonically, the area is part of the Iraqi Zagros Suture Zone (IZSZ), which represents the most deformed area of the ongoing collision between the Arabian and the Turkish micro-continent to the north, and Arabian and Iranian continents towards the northeastern Iraq (Numan, 1997). In a broader scheme IZSZ is a part of the 2000 km long Alpine-Himalayan Mountain Range System (Fig. 1a) (Alavi, 1994, 2004; Othman and

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Gloaguen, 2013).

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The IZSZ is divided into three tectonic subzones: Shalair, Penjwen-Walash and Qulqula-

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Khwakurk subzones (Jassim and Guff, 2006; Lawa, 2013) (Fig. 1b). The study area is structured by Paleocene to Upper Eocene lithostratigraphic units of the Walash Series, within the Penjwen-

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Walash subzone. The Walash Series rocks are covered in places by Quaternary sediments,

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mostly in the form of talus and terrace deposits (Vasiliev and Pentelikov, 1962).

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The main rock types of the Walash Series are sedimentary, volcano-sedimentary and intrusives mostly serpentinised peridotites. Generally, besides the Quaternary clastic sediments and the

The lower Calcareous Shale Group that consists of shales, aphanitic limestones, marls and

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

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intrusive rocks, the sedimentary rocks in Rayat area are grouped as following:

calcareous conglomerates. The aggregate thickness of the Calcareous Shale Group exceeds 800 m, with the middle and upper parts being of late Eocene age, whereas the shales of the lower part are of Paleocene age (Vasiliev and Pentelikov, 1962). 

The middle Volcano-Sedimentary Group, which consists of basalts and other volcanosedimentary rocks, such as breccias, conglomerates, greywackes, sandstones, dolomites and limestone. Aggregate thickness of the Volcano-Sedimentary Group exceeds 1000 m, with the middle part dated to Eocene (Vasiliev and Pentelikov, 1962).

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Journal Pre-proof 

The upper Calcareous-Argillite Group that includes red and light greenish calcareous argillites and gray massive limestone. Subsidiary brown ferruginous conglomerates, red siliceous-jasper rocks and reddish-gray sandstone also occur (Vasiliev and Pentelikov, 1962).

In general an Eocene age was proposed for the Walash Series based on stratigraphic relations (Al-Mehaidi, 1974), whereas the 40Ar–39Ar radiometric dating on its basaltic rocks indicated an

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age range of 24-43 Ma (Eocene-Oligocene) (Ali et al., 2013).

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Besides the sedimentary Groups, intrusive rocks occur as sheets and sills of altered ultrabasic

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rocks. The majority of the intrusive rocks are serpentinites (massive, granular and aphanitic) derived from autometasomatic alteration of ultrabasic rocks; chromite lenses are also present and

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hosted occasionally within the sheared varieties of serpentinites.

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The surface exposure of the ultramafic body at Rayat is relatively small, about 1 km long and

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200 to 400 m wide in plane view (Vasiliev and Pentelikov, 1962) forming a thin lens-shaped sheet striking northeastward (Ismail et al., 2009). Ultramafic rocks mostly are serpentinised and

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only some relicts of primary rocks have been preserved. This serpentinite imbricates

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corresponding to the ophiolitic mélange serpentinites, occur mostly along thrust faults that juxtapose the Qulqula Radiolarite, of the Qulqula-Khwarkurk Subzone, with the overlying Tertiary volcano-sedimentary segment of the Walash Volcano-Sedimentary Group (Aswad et al., 2011). Dating of serpentinite by Rb-Sr method showed ages between 80 and 110 Ma (Aziz et al., 2011). Exotic blocks of metabasalts and metasediments tectonically intermingled with serpentinite-hosted matrix and formed the serpentinite mélange (Aziz et al., 2011).

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Journal Pre-proof During our field work it has been observed that the rock units, which in the previous studies were mentioned as limestone and metamorphic limestone (see Supplementary Information Fig. 1), they actually represent listvenite, being in contact with serpentinite (Fig 2).

3. MATERIALS AND METHODS

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3.1. Field work and mapping

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During field work, a detail geological mapping of the area was conducted and sixteen samples

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were collected from fresh surface exposures along the different parts of the Listvenite outcrop and the surrounding rocks. The field observations assisted to the later desktop remote sensing

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study.

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According to Othman and Gloaguen (2017) Random Forest (RF) and Support Vector Machine

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(SVM) have good accuracy to map geological lithologies. In this work, support vector machine (SVM) method for mapping listvenites by using ASTER (Advanced Spaceborne Thermal

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Emission and Reflection Radiometer) images was applied.

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For remote sensing subsets of the cloud-free level 1B ASTER VNIR & SWIR data (Granules ID: AST_L1T_00308102004074945_20150505144540_24009

and

00308102004074936_20150505144528_88172, acquired on October 8th, 2004), have been processed using the ENVI 4.7. The supervised classification that includes the support vector machine (SVM) was used for identifying listvenites and other lithologies; additionally principal component analysis (PCA) and colour composite were used for confirming the lateral distribution of listvenite and serpentinites.

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Journal Pre-proof For training sample in remote sensing studies, field observations during several field trips combined with previously existing geological map (see SI Fig.1) were used. The map in the scale of 1:20000 is georeferenced and digitized by using ArcGIS version 10.4.3. Subsequently according to field data and observations, 10 training samples corresponding to 9 lithological units and also one class for vegetation as region of interest (ROIs) were chosen. In this study, 56320 pixels as training samples were selected. The ROIs were used to calculate the Support

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Vector Machine (SVM). For accuracy assessment of the final map, the same training samples

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were used. Support vector machine (SVM) method of supervised classification has been used for

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preparing geological map of the area specially focusing on the distribution of listvenite and serpentines, as has been previously also applied (e.g. Heumann, 2011; Mountrakis et al., 2011;

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Brenning et al., 2012; Yu et al., 2012; Puertas et al., 2013; Othman and Gloaguen, 2017).

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3.2. Analytical techniques

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From each sample, thin-polish sections were prepared and examined by using a LEICA

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DM4500P polarized optical microscope. The petrographical examination aimed to the characterization of the mineral assemblages, as well as their textures, and to select the representative regions of interest (ROI) to be studied by means of SEM-EDS. X-ray diffraction (XRD) analysis were performed by using a PANalytical X'Pert PRO MPD Alpha1 powder diffractometer at the facilities of the Research Center of University of Soran, scanning parameters were: 2θ: 6 to 88º with step size of 0.017º and step time of 50 s,. Qualitative evaluation and semi-quantification of the mineral phases was achieved by using High-Score Plus software®.

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Journal Pre-proof Whole rock geochemical analysis for the determination of the major and some minor elements (Ba, Co, Cr, Cs, Cu, Hf, La, Ni, Nb, Pb, Rb, Sc, Sr, V, W, Y, Zn, Zr,) was performed on powdered samples by using a RIGAKU ZSX PRIMUS II spectrometer, equipped with Rh-anode, at the Laboratory of Electron Microscopy and Microanalysis of the University of Patras, Greece. Loss on ignition (LOI) values were determined by combustion of 1g at 950 oC for 2 h (Heiri et al., 2001)

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Inductively Coupled Plasma Mass Spectroscopy (ICP-MS) was applied also for trace element

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concentrations, at SGS commercial laboratory in Canada, by applying lithium borate fusion of

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the sample prior to acid dissolution.

For a more comprehensive evaluation of the mineralogical assemblages, a SEM-EDS

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examination was applied on both polished thin-sections and in some cases on slabs. A FEI 480

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coupled with a BRUKER-QUANTAX energy dispersive X-ray spectroscopy was used at the

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facilities of Scientific Research Center of Soran University. The analytical conditions of the

4. Results

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and count time of 20 s.

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instrument were accelerating voltage of 15 – 20 KV, Beam Current of 20nA, beam size, 1-2 µm

4.1. Listvenite distribution by using remote sensing (RS) techniques

In order to map the listvenite lateral extension, remote sensing techniques were applied, including supervised classification, false colour composition and principal component (Figs. 35).

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Journal Pre-proof 4.1.1. Supervised Classification

The final map shows 9 classes of rock and 1 class for vegetation (Fig. 3). Most of the classes are similar to the ones reported by Vasieliev and Pentelikov (1962), apart from listvenite, slate (corresponding to the phyllite-like shales of Vasiliev and Pentelikov (1962)) and limestone that were identified and mapped in the course of this study. Moreover, according to the new

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observation, the limy conglomerate and ferruginous conglomerate are now included under the

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ferruginous breccia lithology.

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4.1.2. Mapping of listvenite, associated lithologies and zones of alteration

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Spectral characteristics of the listvenite forming minerals show significant absorptions at ASTER

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band 8 (around 2.35 μm), due to C\O bonds (Abrams and Rothery, 1988; Mars and Rowan, 2010). Mineral with ferric iron (Fe3+) in their lattices, such as hematite, magnetite and goethite

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absorb light at ASTER band 1 (0.5 μm and 0.9 μm) (Abrams and Rothery, 1988; Rajendran et

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al., 2011). Minerals containing ferrous iron (Fe2+) absorb light at around 0.65 μm and between 0.9 - 1.0 μm (likely ASTER band 3), 1.8–1.9 μm, and 2.2–2.3 μm, depending on their lattice environment. Magnesite and dolomite produce absorption features near 2.0 and 2.4 μm that are due to hydroxyl bonds (Abrams and Rothery, 1988; Mars and Rowan, 2010). The minerals containing Cr have the depth of the absorption band near 0.55 μm and the best correlations exist between Cr content and spectral reflectance at the wavelength of 0.49, 0.59, 2, 17.5 and 23 μm (Cloutis et al., 2004). Quartz has strong absorption around 0.6 and 2.1 μm.

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Journal Pre-proof For discriminating and mapping listvenite and serpentinite outcrops false colour composite (FCC) images was applied (Fig. 4a) which shows the area of occurrence and spatial distribution of listvenite and for serpentinite; Additionally a composite SVM and FCC map (Fig. 4b) was also produced to confirm the spatial distribution of the two classes of listvenite and serpentinite. The outcome reveals the co-occurrence of listvenite and serpentinite in the broader study area, although in some instances serpentinites are not very evident due to thick soil cover. Remote

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sensing also shows that listvenite bodies have variable sizes and mostly occur as discontinues

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patches.

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Principal component analysis (PCA) is used here to further confirm the presence of listvenite and serpentinite in the study area. The PCA also has a wide application in mapping of zones of

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mineralization and alterations (Amer et al., 2010; Crósta et al., 2003; Loughlin, 1991; Ninomiya

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et al., 2005; Rokos et al., 2000; Tangestani and Moore, 2001; Zhang et al., 2007; Zoheir and

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Emam, 2014).

The Principal Component Analysis (PCA), also known as the Eigen channel transformation,

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packs the information from multiple channels to a smaller number of channels of principal

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components (Loughlin, 1991). It is a linear transformation that rotates the axes of image space along the lines of maximum variance. The rotation is based on the orthogonal eigenvectors of the covariance matrix generated from image data. The output from this transformation is a new set of image channels that assist to enhance and separate certain types of spectral signatures from the background. In this study, the technique is applied to six SWIR bands and the general statistics and principal component eigenvectors and eigenvalues are calculated. The calculated eigenvector matrix is given in Supplementary Information 1 (Table1), which shows the PC1 (see SI 2, Fig. 2a) separating the area of the

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Journal Pre-proof unaltered rock units (i.e. high reflection) from the area of altered rocks (i.e. strong absorption). Because of high absorption in band 4 and high reflection in band 9, the PC2 is chosen as a useful component for illustrating the weathered and altered rocks (see SI 2, Fig. 2b). In addition, because of high absorption in bands 5 and 6 and good reflection in band 8, the PC3 (see SI 2, Fig. 2c) is chosen as a valid indicator for discrimination of mineralized zones. The best RGB image derived from the combination of PC1, PC2 and PC3 bands is given in Fig. 5.

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The principal component bands showed the zones of major alterations (listvenitization) and

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serpentinization. The alteration has occurred along the fault zones shown in Fig. 5b (listvenite as

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black and serpentinites as red colour).

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4.1.3. Accuracy assessment

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In order to estimate how well the resulting classified map by SVM method corresponds with the ground truth the Kappa coefficient (k) and the contingency matrix diagonal has been calculated.

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The Kappa coefficient shows the measurement of agreement between the classified set and the

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true reference data (Cohen, 1960). The contingency matrix delivers the Overall (OA), User’s (UA) and Producer’s (PA) Accuracies (Congalton, 1991). For this purpose, the previously digitized lithological map (see SI 2, Fig. 1) was converted to raster; 56320 test samples (ROIs) were selected randomly from this reference map along with field observation data to assess the accuracy. According to the validation results, the accuracy reaches 72.39 %, which is acceptable (Table 1).

4.2. Field observations

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Journal Pre-proof Based on the outcome of the Remote Sensing Mapping an area near to Rayat village was selected for detailed further study and sampling.

4.2.1. Listvenites

Listvenites in the study area occur like erosional-resistant morphological peaks of variable size,

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and mostly in the form of discontinuous sheet-like bodies 1-5 km wide and from 5 to more than

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20 meters in thickness (Fig. 6 and Fig 7a). The contact to the adjacent serpentinites is a

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progressively transition zone of listvenatized serpentinites (Fig 6. and Fig 7). In most of the cases, a thin layer of gossan-like alteration rich in Fe-bearing minerals covers the

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outcrops of listvenite. This particular mineralization proved to be helpful for the identification of

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listvenite by using remote sensing applications.

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Abundant secondary carbonate minerals (dolomite and calcite) and quartz veinlets are present. Their cross cutting is forming stock work structures (Fig. 6b and c). Generally, the macroscopic

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colour of the hand specimens is grey, although occasionally bright green colours were observed

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due to fuchsite presence (Fig. 8), as well as red when containing siderite (Fig. 8c). The transition zone, representing listvenatized serpentinite, with a thickness of ~2 m displays a grey to green colour. Veinlets of calcite and dolomite can be traced throughout the zone.

4.2.2. Peridotites and Serpentinites

Ultramafic lithologies outcropping close to the listvenites are almost completely altered into serpentinites, apart from occasional small patches still visible within the serpentinites bodies (see

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Journal Pre-proof SI 2, Fig. 3a). The serpentinization of the ultramafic precursors, lead to the alteration of the primary minerals into mineral assemblages dominated by serpentine mineral group and opaque mineral phases. Abundant veins of calcite, dolomite and serpentine inside serpentinites crisscross to form box work structure (see SI, Fig. 3b).

4.3. Mineralogy and petrography of listvenite and associated rocks

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4.3.1. Listvenites

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The results of optical microscopy and X-ray diffraction (XRD) (Figs. 9-10 and Table 2) lead to distinguishing three types of listvenites in the Rayat area: the silica-listvenites, silica-carbonate

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and the carbonate-listvenites. The silica-listvenites occur as veins in the shear zones, developed

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near the transition zones between the listvenite bodies and the adjacent serpentinites, and are

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mainly composed of quartz (Fig. 9e and f). The silica-carbonate type is less abundant than the other two listvenite-types; it is composed of dolomite, calcite, quartz, serpentine and relicts of

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chrome spinels and magnetite (Fig. 10a, b, c and d; Table 2). A characteristic feature of this type

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is the presence of rhythmic banding of quartz and carbonate minerals. Texturally, they contain coarse-grained dolomite and calcite cut by veinlets of quartz (Fig. 10a and b). Carbonate listvenites are composed mostly of calcite and dolomite with minor amounts of quartz and clinochlore (Figs. 9b-d and 10f). Other minerals are Cr-spinels with rims showing alteration to magnetite. The Cr-spinels have subhedral, and anhedral to skeletal form (Figs. 9a and 10d). This type of listvenite shows macro- and micro-sized pores ranging from few microns to 40 microns in diameter respectively, which appear like black spots under the microscope (Fig. 10e). These voids in the carbonate listvenite provide clear textural evidence for incipient alteration-

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Journal Pre-proof dissolution by percolating fluids and subsequent weathering of less competent materials. The euhedral crystals of dolomite with well-formed cleavage indicate an in situ crystallization.

4.3.2. Transition Zone

The mineralogy of listvenite-serpentinite transition zones are dominated by dolomite, chrysotile,

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and minor amount of chromian spinel (Table 2). SEM-EDS revealed the presence of remnants of

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the original chrysotile, which are not affected by carbonation (Fig. 11a and b). In several cases

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the original fibrous form of chrysotile remained but the chemical composition altered leading to the formation of dolomite pseodomorph after chrysotile (Fig. 11a). Hence the presence of non-

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altered and altered chrysotile in this rock indicates the occurrence of carbonic alteration

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processes that affected the primary lithologies.

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4.3.3. Peridotites and Serpentinites

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The peridotites are composed of serpentine as major mineral. Common minerals are olivine and pyroxene with minor amount of chromite, magnetite and hematite. Olivine and pyroxene are replaced by serpentines mostly in fractures and along cleavage lines and display mesh texture (see SI 2, Fig. 4a). Serpentines are mostly lizardite and chrysotile. Chromite and Cr-Spinel are present as individual grains, which are subjected to brecciating and in some parts veins of serpentine traverse them. They occur as euhedral to anhedral disseminated crystals that commonly range from 10 to 500 μm in size (see SI 2, Fig. 4b). Hematite is mostly formed as small grains inside the fractures between polygonal parts of olivine.

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Journal Pre-proof Serpentine and minor amount of pyroxene, calcite and some relicts of olivine dominate the serpentinites. Opaque minerals are chromite and magnetite. Serpentine filled fractures between primary minerals such as olivine and pyroxene while in some parts it has replaced primary minerals completely. XRD results show that the types of serpentines are lizardite and antigorite (Table 2). Optical microscopy of thin sections also revealed the stockwork structure, which is

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formed by the crosscutting of veins of calcite and serpentine minerals (see SI 2, Fig. 4c and d).

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4.3.4. Fuchsite in Rayat listvenite

Fuchsite (K(Al,Cr)3Si3O10(OH)2) occurs as loose material within the fractures of the carbonate

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listvenite (Fig. 12a) and as pore filling and veinlet in between the minerals of silica listvenite

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(Fig. 12a and e; sample AZ7-5). The fuchsite shows pale green colour macroscopically, and

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intense green colour in polished sections (Fig. 12a, b, c). Sample G1 that represents a vein filling is composed of intergrowth of fuchsite as major and quartz as minor phase with some trace

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amount of antigorite and spinel (Table 2). Under SEM it shows sheet-like texture similar to other

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minerals of mica group (Fig. 12d and e).

4.4. Mineral Chemistry

Almost all carbonate minerals in the listvenite samples contain Fe and Mg in the range of 0.2714.59 wt.% and 1.59-26.20 wt.%, respectively (see SI 1, Table 2 and Fig. 11c and e), revealing a considerable compositional variability. Birnessite has been identified in two samples AZ7-4 and AZ7-5, which display high Mn values (avg. 33.41 and 13.65 wt.% MnO respectively). SEM-

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Journal Pre-proof EDS results indicate that fuchsites contain 7.3 wt% in average of Cr2O3 concentration; Ni average content value is of 0.313 wt.%, whereas K2O shows high concentration (avg. 5.18 wt.%); moreover SiO2, Al2O3, Fe2O3 and MgO show high concentration in fuchsite. Sample RA-0 from the transition zone is composed mainly by dolomite with avg. 58.82 wt.% of CaO and avg. 20.99 wt.% of MgO, and fibrous chrysotile (avg. 42.20 wt.% SiO2 and 42.69 wt.% MgO). Other phases that were identified have composition between dolomite and chrysotile with

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avg. 27.39 wt.% of CaO, 34.71 wt.% of MgO and 27.59 wt.% of SiO2.

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The SEM-EDS data show variations in the chemistry of the serpentine, pyroxene and olivine

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minerals, contained in the peridotite (sample AZ8-0). The olivine is richer in Mg (avg. 42.23 wt.% MgO), whereas pyroxene is richer in Si (avg. 52.03 wt.% SiO2) and Al (avg. 2.20 wt.%

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Al2O3). Serpentines have lower amount of Mg and Si but higher amount of Cr (avg. 1.11 wt.%

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Cr2O3) related to olivine and pyroxene. There is no significant variation in the concentrations of

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the rest major elements in these minerals. Trace elements concentration such as Ni in olivine and pyroxene is higher than in serpentines. Serpentines of serpentinites show higher content of Mg

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than in peridotite. Pyroxene of serpentinites shows lesser amount of Mg (avg. 24.11 wt.% MgO)

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and Si (avg. 20.58 wt.% SiO2), but high concentration of Ca (avg. 22.10 wt.% CaO).

4.5. Whole rock geochemistry 4.5.1. Major oxides The silica-listvenites are typically enriched in SiO2, but depleted in almost all the other major elements (Table 3). The carbonate-listvenites are generally enriched in CaO, whereas the silicacarbonate listvenites contain moderate values of SiO2, CaO and MgO, as expected. The low MgO values, less than 19 wt.%, in almost all types of listvenites suggest that magnesite mineral

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Journal Pre-proof has not been form as component of listvenite in Rayat area unlike other types around the world (e.g. Hinsken et al., 2017). Potassium and sodium show in general very low values almost in all types of listvenites consistent with their formation as Arc Massif listvenites of ultramafic protolith (Aydal, 1990). Only in samples containing fuchsite the contents of K2O (6.2 wt.%) and Na2O (0.07 wt.%) are elevated, whereas the occurrence of high contents of Al2O3 (16.37 wt.%) and Cr (16872 mg/kg) are related to the presence of chrome spinels. High values of Fe2O3 (9.04

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wt.%) are attributed to the presence of ankerite, spinel, magnetite and their supergene-related

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iron oxides.

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The diagrams of MgO–CaO–SiO2 (Fig. 13a) and SiO2-Fe2O3-CaO+Mg (Fig. 13b) indicate that the listvenite samples are separated from other associated rocks, and that they can be grouped in

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the three above mentioned classes, i.e. of silica-, carbonate- and silica-carbonate listvenites.

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4.5.2. Minor and rare earth elements

Minor and rare earth element composition are shown in Table 3. The contents of Zr, Hf, V, Ba,

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Sr, Rb, Ga, Ta, Nb, and Th of silica listvenite are elevated due to the presence of fuchsite mica,

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whereas in the other two types are close to the background contents of the ultrabasic rocks (McDonough and Sun, 1995). Chondrite-normalized REE patterns for peridotite, serpentinite, listvenite-serpentinite and the listvenite veins are shown in (Fig. 14). The rare earth element patterns in all the studied lithologies are quite similar, being quite depleted and displaying a relatively zigzag U-shaped patterns, similar to that of metasomatized mantle (Zhou, 2004; Tsikouras et al., 2006). Rare earth element concentrations in most samples are very low, with an average REE total of 1.06 mg/kg for listvenites, 0.98 mg/kg for serpentinites, 1.06 mg/kg for peridotites (Table 3). In more details, the average LREE total is 1.15 mg/kg in listvenites, 1.02

17

Journal Pre-proof mg/kg in serpentinites and 1.18 mg/kg in peridotite; accordingly, the average HREE total is 0.96 mg/kg in listvenites, 0.94 mg/kg in serpentinites and 0.94 mg/kg in peridotite. The best approach for separating different types of listvenites is by applying scatter diagrams (Akbulut et al., 2006; Çolakoglu, 2009). Accordingly, Figure 13 illustrates moderate to good separation and correlation among MgO+CaO–LOI (Fig. 13d) and MgO+CaO–SiO2 (Fig. 13c),

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displayed for all the samples.

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5. Discussion

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5.1. Geochemical gain and loss of elements: Mass Balance Calculations

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Elemental losses and gains that accompany alteration in rocks were calculated using the

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chemical mass balance model (Brimhall and Dietrich, 1987; Anderson et al., 2002) and the

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formula:

𝐶𝑗, 𝑤 𝐶𝑖, 𝑝 + −1 𝐶𝑗, 𝑝 𝐶𝑖, 𝑤

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𝜏𝑗, 𝑤 =

Where [𝜏𝑗, 𝑤] represents loss or gain of elements, C refers to concentrations of immobile (i) or

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mobile elements (j) in parent (p) or altered material (here listvenite) (w). Yttrium was selected as the immobile element. The model is predicated on identification and characterization of the parent rock. The measured values are considered as either positive values (gains) or negative values (loss). The results of mass balance calculations are illustrated in Figs. 15-16 (see SI 1, Table 3) According to the results SiO2, CaO and K2O are added to silica listvenites in the form of clear-cut quartz- and carbonate- veins and fuchsite. Carbonate listvenites are significantly enriched in CaO and P2O5 but show loss of SiO2, Fe2O3, MnO and MgO component. Silicacarbonate listvenites gained moderate values of CaO and P2O5. Listvenite - serpentinite shows

18

Journal Pre-proof great losses in SiO2, Fe2O3, and MgO, and on the contrary moderate gain in CaO; they are depleted in most of the trace elements. On the other hand, TiO2, K2O and Al2O3 do not show significant gains or losses in all types of the listvenites except silica listvenite. Serpentinites underwent variable geochemical alterations, including both enrichment and depletion of the major oxides and minor elements. For example, they are depleted from SiO2, MgO, Ni, Cu, Nb, Zr, and Cr, whereas they are enriched in CaO and Pb. Finally, silica listvenites gained Cr and K

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as a result of fuchsite presence.

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5.2. Statistical evaluation - Factor analyses

Statistics software

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Factor analyses (Davis, 1986) has been implemented by using IBM SPSS

in order to gain a grouping of samples according to geochemical affiliations. The outcome

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revealed a 4-factor model that covers 78% of the total variance of the eigenvalues, with all factors displaying a bipolar mode (see SI 1, Table 4). By correlating the factor loadings the

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following groupings and affiliations were obtained (Fig. 17a and b). 

Al, Ba, Cr, K, Na, Rb, Ti, V, (Nb) indicating their affiliation in fuchsite;



Fe, Mg, Ni, Cu, (Mn), are grouped due to their co-existence in the ultramafic mineral phases;



Ca, P, Ce, (LOI, Sc) are associated to enrichment processes during the listvenitization (e.g. AZ7_3, AZ7_4), being in accordance to the results obtained from Mass Balance Calculations ;

19

Journal Pre-proof 

Y, Zr, (Sr) grouping is revealed particularly in sample RA0 and secondary in AZ7_9, reflecting probably the immobile character of these elements;



Si and Nb grouping in most of the samples;



Hf, Zn, La, Cr, Pb are grouped together probably due to the existence of heavy minerals particularly in sample AZ7_1 and AZ7_2.

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By plotting the factor scores (Fig. 17b) a clear grouping of the samples can be observed. Apart

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from sample G1 that corresponds to fuchsite the rest samples are lined up parallel to the Fs2 axis

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from the least affected peridotite to the most affected samples due to listvenitization.

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5.3. Rayat listvenite protolith and formation

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The listvenitization process involves the formation of new carbonate and silicate minerals by replacement of the silicates, such as serpentine and rarely olivine and pyroxenes in ultramafic

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rocks (Spiridonov, 1991); in this process, silicates are donating the bivalent metal cations Fe, Mg.

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For listvenite formation the introduction of elements such as K, Si, Ca, Mg, etc. is crucial (Akbulut et al., 2006). The amount of Ca in the carbonate depends on relative abundance of calcic silicates, such as diopside in the original rock and the influx of Ca in the hydrothermal fluid. As a result of the breakdown of the silicates and the fixation of Fe-Mg-Ca in carbonates, silica is released to form quartz (Sazonov, 1975; Hall and Zhao, 1995; Uçurum, 2000). During serpentinization by hydrothermal activity, serpentinite may be progressively transformed into different types of listvenite rocks. Listvenitization occurs in the shear, thrust and faulted fractured porous zones of ultramafic rocks, which act as pathways for altering fluids. Most

20

Journal Pre-proof researchers proposed listvenitization to post-date serpentinization of ultramafic rocks and to be superimposed on the earlier serpentinite (e.g., Spiridonov 1991; Uçurum 2000).

In Rayat area field and mapping data show that listvenite is in contact to serpentinites along a transitional zone, which is dominated by carbonate minerals and chrysotile. The REE patterns, the significant amount of Cr-K-rich fuchsite, clinochlore, and chrome-spinel (rich in Ni), as well

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as the presence of a transition zone between listvenites and serpentinised peridotite indicate

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origin from hydrothermally altered ultramafic source rocks. Hence the protolith of the Rayat area

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is the serpentinised peridotite and in Figure 22 a descriptive model is suggested. The serpentinites of the Rayat area are isolated bodies representing serpentinised for-arc mantle

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wedge peridotites, were emplaced through diapiric upwelling into non-accretionary for-arc

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tectonic setting during Paleocene to Eocene (Mohammad, 2009). The parent rocks of

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serpentinites are less depleted harzburgite to lherzolite, similar to the AZ8_0 sample in our study. Serpentinization of the peridotites occurred due to slab derived fluids in mantle wedge.

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Dehydration reactions and sediment pore water expulsion from subducted material and the

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subsequent porosity reduction could result in rising up of slab-derived fluids and finally leading to serpentinization of upper mantle rocks in for-arc (Mohammad, 2009). This assumption is supported by the association of serpentinite with the spilite and andesite of the Walash volcanic arc rocks related to a Paleocene–Eocene magmatic arc (Numan, 2001). According to the field observation fracturing of serpentinites due to fault zone reactivation subsequent to emplacement permitted CO2- and Ca-K-Si-Mg-rich groundwater circulation and alteration of the serpentinite and serpentinized peridotite, leading to the formation of listvenite during Oligocene-Miocene. The field relationships of the lithological alternations, as well as

21

Journal Pre-proof petrographical observations like the metasomatic alteration of serpentine to carbonate minerals, support the above statement. Moreover, chromite, the most refractory primary mineral in ultramafic rocks, generally survives during the processes of metamorphism/hydrothermal alteration and is preserved within the listvenite mineral assemblages; hence the occurrence of chromite provides additional evidences of the ultramafic origin of Rayat listvenite (Irvine, 1967). Different types of listvenite correspond to differences in the mineralogical and geochemical

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features of the protoliths, as well as different stages of hydrothermal alteration, leading to

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different phases of metasomatic replacement (Nasir et al., 2007). Accordingly, variations on the

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range of pH, temperature and CO2 fugacity lead to the formation of the different type of listvenites in Rayat area. Carbonate listvenites to form require high CO2 fugacity, pH range of 8–

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10 and moderate-high temperature (Ash and Arksey, 1990; Uçurum, 2000); under high alkalinity

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conditions (pH>11) primary minerals like olivine, pyroxene and their alteration products, such as

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serpentines altered (Neal and Stanger, 1983) and resulted in a loss of material and a creation of zones of high porosity. Similar conditions prevailed for the formation of the Rayat carbonate

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listvenite, which were the first to be developed.

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Silica-carbonate listvenites of the studied area could form in different ranges of pH and CO2 fugacity (Sazonov, 1975; Boschi et al., 2009). A maximum temperature range between 350 and 400 °C is suggested for a stable quartz-dolomite assemblage at xCO2 values varying between 0.1 and 0.5 at 1 kbar (Weir and Kerrick, 1987; Auclair and Gauthier, 1993). Finally, silica listvenites were formed by the precipitation of Si from the circulated hydrothermal fluids; apart from magmatic origin the Si was enriched in the fluids due to the dissolution of the primarily serpentine minerals during the initial carbonate phase of listvenitization.

22

Journal Pre-proof Additional characteristic features of the Rayat listvenite is the significant occurrence of fuchsite mineral, which is rich in Cr and K and occurs commonly in metasomatized ultramafic rocks (Brigatti et al., 2001). Fuchsite was formed from Cr that was mobilized from the chrome-spinel or Cr-bearing silicates of the ultramafic host rocks (Hall and Zhao, 1995) and K that was delivered by the carbonic hydrothermal fluids (Abovian, 1978), as the ophiolitic ultramafic rocks have very low ( < 0.01 wt%) K2O.

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Finally, the carbonate minerals, i.e. ankerite, dolomite and calcite, of the Rayat listvenites are

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rich in Fe, and the modern atmospheric weathering results in limonite formation, which

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consequently gives a yellow-brown colour to listvenite in the field (gossan-like).

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5.4. True listvenite (?) and implications for mineral exploration

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According to Rose, (1837); Aydal, (1990) and Spiridonov, (1991) definition, the Rayat area listvenites are true listvenite because they are linked to ultramafic rocks, while listvenite-like

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metasomatites are associated with the plutogenic granitoid rocks. In addition, the Rayat listvenite

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has experienced potassic metasomatism beside carbonization. The identification of the listvenite in Rayat area as a metasomatic hydrothermal alteration process, upgrades the area regarding potential epithermal mineralizations of Cu, Au etc. (e.g. Aftabi and Zarrinkoub, 2013; Belogub et al., 2017). The data of this study shows a depletion of Ni and Cu from the serpentinites due to the listvenitization, which in turn implies that these elements were dissolved in the hydrothermal fluids and when conditions were favorable, they precipitated. The only elements of economic interest that show some relative enrichment are Cr and V, however they are bounded in fuchsite, hence their exploitation is questionable. As it was

23

Journal Pre-proof out of the scope of this study, a detail future prospecting of the area, tracing the hydrothermal veins within the listvenite bodies in the broader area is suggested.

6. Conclusions Geological observation and geochemical data in combination with petrography lead to the following conclusions: The listvenitization in the Rayat area occurred due to hydrothermal alteration of the

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



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and Co supports also the ultramafic protolith.

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serpentinised peridotite that extensively occurs in the area. The enrichment mode of Cr, Ni

Remote sensing mapping was successfully applied to identify the spatial distribution of the

Petrographical and geochemical data indicate three types of listvenite in the study area: a)

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

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listvenite as gossan type oxidations covering the outcrops.



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silica listvenite, b) carbonate listvenite and c) silica carbonate listvenite. A predominant feature of the Rayat listvenite is the extensive occurrence of fuchsite

A preliminary estimation of the listvenitization process indicates that it occurred after the

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

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intergrowths with quartz along fractures of the silica- and carbonate listvenites.

serpentinization of the ophiolitic suite, which took place between Paleocene to Eocene. This means that listvenitization might have occurred in Oligocene-Miocene during or after continental collision of Arabian and Iranian plates. 

The mechanism of listvenitization involved the impact of hydrothermal fluids circulation upwards along fault zones, with the fluids being alkaline and rich in CO2, CaO, SiO2, and K2O.

24

Journal Pre-proof 

Further research is needed, which will encompass isotopic and fluid inclusion studies in order to gain more solid clues for the exact forming mechanism and the age of the listvenitization process in Rayat area. Additional detail geochemical program might reveal any potential mineralizations often associated to listvenites.

Acknowledgements

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The authors would like to thank the Scientific Research Center of Soran University for SEM,

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XRD and Microscopy lab facilities, as well as the following persons from the University of

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Patras: Dr. V. Xanthopoulou, Laboratory of Electron Microscopy and Microanalysis, Faculty of Natural Sciences, for conducting the XRF analysis and Mr. Nikolaos Sofis, for assisting in

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sample preparation.

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pp.121–135. Available at: . Rajendran, S., Thirunavukkarasu, A., Balamurugan, G. and Shankar, K., 2011. Discrimination of iron ore deposits of granulite terrain of Southern Peninsular India using ASTER data. Journal of Asian Earth Sciences, [online] 41(1), pp.99–106. Available at: . Rokos, D., Argialas, D., Mavrantza, R., St.-Seymour, K., Vamvoukakis, C., Kouli, M., Lamera, S., Paraskevas, H., Karfakis, I. and Denes, G., 2000. Structural analysis for gold mineralization using remote sensing and geochemical techniques in a GIS environment: Island of Lesvos,

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Journal Pre-proof Hellas. Natural Resources Research, 9(4), pp.277–293. Rose, G., 1837. Mineralogisch-geognostische Reise nach dem Ural, dem Altai and dem Kaspischen Meere. Volume 1: Reise nach dem nördlichen Ural and dem Altai. C.V. Eichhoff Verlag der Sanderschen Buchhandlung, Berlin xxx plus 641 p. and plates I– VII. Sazonov, V.N., 1975. Listvenitization and Mineralization (Listvenitizaciya orudeneniye) Izdatelistvo Nauka. Science Publishers, Moscow.

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Spiridonov, E.M., 1991. Listvenites and zodites. International Geology Review, 33(4), pp.397–

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407.

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Tangestani, M.H. and Moore, F., 2001. Comparison of Three Principal Component Analysis Techniques to Porphyry Copper Alteration Mapping: A Case Study, Meiduk Area, Kerman, Iran.

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Tsikouras, B., Karipi, S., Grammatikopoulos, T.A. and Hatzipanagiotou, K., 2006. Listwaenite evolution in the ophiolite mélange of Iti Mountain (continental Central Greece). European

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Journal of Mineralogy, 18(2), pp.243–255.

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Uçurum, A., 2000. Listwaenites in Turkey: Perspectives on formation and precious metal concentration with reference to occurrences in east-central Anatolia. Ofioliti, 25(1), pp.15–29. Vasieliev M.M. Pentelikov, V.G., 1962. Report on prospecting exploration of Bard-i-Zard chromite occurrence and adjacent areas. Technoexport Report, No. 298, Geological Survey Mineral Investi- gation. Vasiliev, M.M. and Pentelikov, V.G., 1962. Report on prospecting exploration of Bard-i-Zard chromite occurrence and adjacent areas. Technoexport report, Geol. Surv. Min. Investigation Library, (298).

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Journal Pre-proof Weir, R.H. and Kerrick, D.M., 1987. Mineralogic, fluid inclusion, and stable isotope studies of several gold mines in the Mother Lode, Tuolumne and Mariposa Counties, California ( USA). Economic Geology, 82(2), pp.328–344. Yu, L., Porwal, A., Holden, E.-J. and Dentith, M.C., 2012. Towards automatic lithological classification from remote sensing data using support vector machines. Computers & Geosciences, [online] 45, pp.229–239. Available at:

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Zhang, X., Pazner, M. and Duke, N., 2007. Lithologic and mineral information extraction for

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gold exploration using ASTER data in the south Chocolate Mountains (California). ISPRS Journal of Photogrammetry and Remote Sensing, [online] 62(4), pp.271–282. Available at:

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.

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Zhou, M.F., 2004. REE and PGE Geochemical Constraints on the Formation of Dunites in the

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Luobusa Ophiolite, Southern Tibet. Journal of Petrology, [online] 46(3), pp.615–639. Available at: .

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Zoheir, B. and Emam, A., 2014. Field and ASTER imagery data for the setting of gold

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mineralization in Western Allaqi–Heiani belt, Egypt: A case study from the Haimur deposit. Journal of African Earth Sciences, [online] 99(PA1), pp.150–164. Available at: . Zoheir, B. and Lehmann, B., 2011. Listvenite–lode association at the Barramiya gold mine, Eastern Desert, Egypt. Ore Geology Reviews, [online] 39(1–2), pp.101–115. Available at: .

35

Journal Pre-proof Figure 1. Simplified geological map of the Iraqi Zagros Suture Zone along Iraq-Iran border (after Moores et al., 2000) and modified by (Sissakian, 2000), showing the study area. Figure 2. Updated geological map of the Rayat area according to this study (modified from Vasiliev & Pentelikov, 1962). Figure 3. Lithological map of study area using Support Vector Machine (SVM). Figure 4. ASTER RGB (8, 6 and 1 bands) image showing the occurrence and spatial distribution

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of listvenite, (a) listvenite extending in the yellow areas and serpentinite the blue areas. (b)

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listvenite extending in black areas, whereas serpentinite in red areas.

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Figure 5. Principal component analysis R: PC1, G: PC2, B: PC3 of the Rayat area, (a) listvenite

areas, whereas serpentinite in red areas.

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extending in the blue areas and serpentinite the green areas. (b) listvenite extending in black

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Figure 6. Field photos of listvenites in Rayat area. The listvenites form brown to yellow crests

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attributed to the alteration of ferromagnesian minerals (a, b and c). (a) Contact zone between listvenites (Lis) and serpentinite (Serpt). (b) Yellowish listvenite showing quartz stockwork

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structure. (c) Yellow brown listvenite traversed by up to cm-thick quartz veins.

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Figure 7. Listvenite outcrop showing direct contact with serpentinites in Rayat area. (a) Listvenites (brown colour) in contact with serpentinites (dark blue color). (b) Gradational contact (‘transition rock’) between listvenites and serpentinites. (c) Listvenite-serpentinite contact. (d) Listvenitised serpentinite marking a transition zone between listvenite and serpentinite. The transition lithology is grey to green in colour due to the presence of dolomite and serpentinite. Secondary veins of serpentinite and calcite are also present. Figure 8. Listvenites outcropping in Rayat area. (a) Multi-colored brecciated listvenites. (b) Listvenites containing fragments of carbonate minerals, quartz and fuchsite with green color. (c)

36

Journal Pre-proof listvenites with red to brown colour due to presence of ankerite. (d) Large veins of secondary dolomite crosscutting listvenite. (e and f) Distribution of fuchsite veins inside listvenite fractures. Lis: Listvenite, Dol: Dolomite, Fuch: Fuchsite. Figure 9. Photomicrographs showing mineralogical composition and microstructural characteristics of Rayat listvenites under cross-polarized light: (a) chrome spinel inside listvenite; alteration rims to magnetite are evident. (b) Veins of dolomite and quartz crosscutting

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inside listvenite. (c) Rhombohedral dolomites showing perfect cleavage in carbonate listvenite.

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(d) Dolomite in carbonate listvenite with clinochlore background. (e) Silica listvenite displaying

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secondary veins of quartz that cut fine grain quartz as matrix. (f) Silica listvenite displaying relict mesh texture of primary serpentinite. Clc: clinochlore; Qz: quartz.

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Figure 10. Photomicrographs showing mineralogical composition and microstructural

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characteristics of Rayat listvenites: (a, b, c and d) Silica carbonate listvenite showing quartz,

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dolomite, calcite and spinel minerals. (a) Secondary veins of calcite and quartz cuting through calcite matrix. (b and c) Quartz and calcite veins as as stockwork structure. (d) Presence of

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disseminated Cr-spinel with mostly skeletal textures and subhedral shape. (e and f) Carbonate

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listvenite (e) Presence of clinochlore and calcite as matrix and porous space as black spots, which show the weathering of least resistance mineral. (f) Presence of calcite with different shapes and size. Qz; quartz, Dl; dolomite, Cal; calcite, Clc; clinochlore. (a sample AZ7-6), (b, c and d;sample AZ7-7), (e and f; sample AZ7-4). Figure 11. SEM images of Listvenite rocks from Rayat area: (a) Formation of dolomite due to alteration; replacement of chrysotile by dolomite, remnants of chrysotile as needle (red arrow). (b) Chrysotile remnant of parent serpentinite, which is preserved from alteration. (c) Fuchsite mineral occurring as veinlet, as well as pore filling, in addition of a remnant of dolomite crystal

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Journal Pre-proof (sample; AZ7-5). (d) Dolomite crystals showing dissolution alteration caused by circulating fluids (sample; AZ7-3). (e) Converting of dolomite to ankerite (sample AZ 7-3). (f) Presence of clinochlore between carbonate minerals of listvenite (sample AZ7-4). Ank: ankerite, Cal; calcite, Clc: Clinochlore, Dol: Dolomite, Fuch: fuchsite, Qz; quartz. Figure 12. Hand specimen and photomicrograph of fuchsite sample (G1 and az7-5) from Rayat area. (a) Hand specimen of fuchsite as loose material from fracture filling of carbonate listvenites

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(G1). (b) Fuchsite, which filled pores and spaces between quartz listvenite (sample AZ-7-5). (c)

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Fuchsite with intense green colour in reflected light. (d and e) SEM image of quartz and fuchsite;

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(d) Fuchsite filled pores between quartz. (e) Sheet-like texture of fuchsite like mica group (Fuch: fuchsite, Qz: quartz).

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Figure 13. Ternary and scatter diagrams for different types of listvenites and associated rocks in

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the Rayat area; a and b discrimination of different types of listvenite based on chemical

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composition (after Akbulut et al., 2006), c and dscatter plots of CaO+MgO vs. SiO2 and CaO + MgO vs. SiO2 for discriminating different types of listvenite (after, (Çolakoglu, 2009).

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According to plots there are 3 types of listvenite as Carbonate listvenite (C.L), Silica listvenite

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and silica carbonate listvenite.

Figure 14. Chondrite normalized REE spider diagram patterns of the peridotite (Per), serpentinite (Ser), carbonate listvenite (C.Li), silica listvenite (Si.Li) and the slilica carbonate listvenite (Si.C.Li); normalization values are from (McDonough & Sun, 1995). Figure 15. Mass balance changes of some major elements in the listvenites, listvenitised serpentinite and serpentinite. Horizontal lines represent the least altered peridotite composition. Figure 16. Mass balance changes of some minor elements in the listvenites, Listvenitised serpentinite and serpentinite. Horizontal lines represent the least altered peridotite composition.

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Journal Pre-proof Figure 17. Scatter plots of the 1st vs. 2nd factors: a) factor loadings and b) factor scores. (a) factor loading, which provide grouping of the chemical elements, (b) factor scores, which provide grouping for the samples.

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Figure 18. Suggested model for listvenitization in Rayat area, NE Iraqi Kurdistan.

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Journal Pre-proof Table 1. Assessment of the classification accuracy. Kappa Coefficient

Kappa %

77.45%

0.7239

72.39

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Overall Accuracy

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Journal Pre-proof Table 2. XRD results of mineral composition of different types of Listvenites and associated rocks. Sample AZ7-7 AZ7_9 AZ7_4 AZ7_3 G1 AZ7_5 AZ7_10 AZ2 RA0 AZ8a_2 AZ8a-1 AZ8_1 AZ8-2 AZ8_0

L_Type1 Fch. C.Li C.Li C.Li S.C.Li Fuchsite M S.Li T S.Li Lis-Ser Lis-Ser Ser Ser Ser Ser Peri

Q m m M T M M

Dol. Calc. Ank. Sp. M T T M T M T m T T T T T M T T M T T T M m T m T m

1:

Cln.

Liz. Ant. Hem. Tlc. Fa.

Mg.

Px. Bi.

T m

f o

T

o r p

T

M

l a

M M m M M

e

M M M M M

r P

T T

T

T T T T T

T

m m m T T

C.Li.: Carbonate Listvenite, S.Li.: Silica Listvenite, S.C.Li.: Silica-carbonate Listvenite, Ser.: Serpentinite, Peri.: Peridotite, Lis-Ser.: Listvenitised serpentinite. : M: main, ), m: minor, T: trace.

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2

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Journal Pre-proof Table 3. Geochemical results of the studied Rayat samples. Sample Elements in % Al2O3a CaO a Fe2O3 a K2O a MgO a MnO a Na2O a P2O5 a SiO2 a TiO2 a LOI % Total in mg/kg Ag b As b Ba a Be b Bi b Co a Cr a Cs b Cu a Ga b Ge b Hf a Li b Mo b Ni a Nb a

C.Li AZ7_7

C.Li AZ7_9

C.Li AZ7_4

S.C.Li AZ7_3

S.Li G1

S.Li AZ7_1

S.Li AZ7_2

S.Li AZ7_5

S.Li AZ7_10

T AZ2

T RA0

Ser AZ8a_1

Ser AZ8a_2

Ser AZ8_1

Ser AZ8_2

Peri AZ8_0

0.21 26.08 4.21 <0.01 10.57 0.06 0.01 0.01 12.48 0.01 35.28 88.92

4.91 20.34 9.04 <0.01 19.11 0.04 0.01 <0.01 12.62 0.08 36.36 102.51

1.58 42.98 5.65 0.04 1.92 0.15 0.04 0.04 13.52 0.03 33.01 98.96

0.36 19.52 3.24 0.01 5.04 0.06 0.01 0.03 49.7 0.01 18.37 96.35

16.37 1.82 2.19 6.19 3.37 <0.01 0.08 0.01 38.64 0.81 9.68 79.16

10.49 7.36 6.32 2.34 10.02 0.03 0.04 0.01 42.36 0.53 11.39 90.89

4.68 13.8 3.83 0.25 6.83 0.06 0.01 0.02 55.5 0.16 12.96 98.08

6.38 2.83 2.65 1.98 4.06 0.02 0.04 0.01 75.19 0.27 5.71 99.13

0.28 6.74 5.26 0.01 10.24 0.03 0.01 <0.01 65.72 <0.01 13.37 101.68

e

0.12 20.58 5.66 <0.01 18.97 0.07 0.01 <0.01 34.27 0.01 21.1 100.79

<0.01 12.89 5.43 0.01 23.74 0.27 0.01 0.01 30.31 0.01 30.84 103.52

0.24 10.34 5.61 <0.01 32.76 0.09 <0.01 <0.01 29.21 0 18.64 96.9

0.19 6.27 7.2 <0.01 34.71 0.1 <0.01 <0.01 29.18 0.01 16.33 93.99

0.18 10.84 8.12 <0.01 31.78 0.18 0.01 0.01 28.51 0 19.38 99.02

0.3 10.39 7.09 0.01 29.51 0.13 <0.01 0.01 29.76 0.01 18.51 95.71

0.19 0.05 7.15 <0.01 38.1 0.14 <0.01 <0.01 41.01 0.01 13.74 100.39

<1 20 <1 <5 <0.1 37 3053 <0.1 335 <1 <1 <1 <10 3 1029 3

na na <1 na na 133 2083 na 455 na na <1 na na 3105 <1

<1 20 30 <5 <0.1 96 1545 0.3 379 1 <1 12 <10 <2 1144 <1

<1 14 <1 <5 <0.1 120 812 0.2 265 <1 <1 40 <10 <2 801 2

<1 <5 204 <5 <0.1 23 13246 62.2 536 21 <1 <1 <10 <2 1633 9

<1 22 <1 <5 <0.1 113 16872 14.3 1253 10 1 85 40 <2 3767 2

<1 <5 54 <5 <0.1 87 9517 12.8 630 6 <1 14 14 <2 1747 4

na na <1 na na 114 1932 na 33 na na 4 na na 181 <1

na na <1 na na 89 2258 na 1397 na na <1 na na 4310 7

na na <1 na na 154 3090 na 571 na na <1 na na 3911 <1

na na 6 na na 94 1244 na 1446 na na 1 na na 4468 3

na na <1 na na 110 1742 na 1833 na na 3 na na 5646 3

<1 <5 10 <5 <0.1 120 1762 0.3 1930 <1 <1 1 <10 <2 5966 2

<1 <5 6 <5 0.2 102 1349 0.2 1680 <1 <1 1 <10 <2 5193 2

<1 <5 30 <5 <0.1 105 1881 <0.1 2027 <1 <1 2 <10 <2 6242 4

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l a <1 11 25 <5 <0.1 118 5272 1.4 686 4 <1 23 26 <2 2060 3

r P

42

f o

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Journal Pre-proof Table 3. Continues. Pb a Rb a Sb b Sc a Sn b Sr a Va Ub Wa Ya Zn a Zr a Ce a Dy b Er b Eu b Gd b Ho b La b Lu b Nd b Pr b Sm b Ta b Tb b Th b Tl b Tm b Yb b

21 0.2 <0.1 <1 <1 158 11 0.06 4 3 50 8 <0.1 <0.05 <0.05 <0.05 <0.05 <0.05 <0.1 <0.05 <0.1 <0.05 <0.1 <0.5 <0.05 <0.1 <0.5 <0.05 <0.1

7 3 na 31 na 422 71 na <1 11 49 19 na na na na na na na na na na na na na na na na na

21 3 0.3 44 <1 32 35 0.19 148 5 86 19 1 0.19 0.1 0.05 0.17 <0.05 0.8 <0.05 0.7 0.19 0.2 <0.5 <0.05 0.2 <0.5 <0.05 0.1

24 <0.5 na 43 na 46 3 na 4 3 46 17 na na na na na na na na na na na na na na na na na

17 0.6 0.7 52 <1 100 15 0.13 494 4 46 10 0.2 0.1 0.06 <0.05 0.08 <0.05 0.1 <0.05 0.1 <0.05 <0.1 0.6 <0.05 <0.1 <0.5 <0.05 <0.1

5 131 0.2 80 <1 21 959 <0.05 2 5 42 20 0.2 0.14 0.11 <0.05 0.08 <0.05 <0.1 <0.05 <0.1 <0.05 <0.1 <0.5 <0.05 <0.1 <0.5 <0.05 <0.1

l a

n r u

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31 64 0.1 32 <1 12 390 0.1 2 5 378 18 0.3 0.22 0.16 <0.05 0.16 0.05 0.1 <0.05 0.3 0.05 <0.1 <0.5 <0.05 <0.1 <0.5 <0.05 0.1

15 6 0.1 46 <1 24 125 0.06 289 4 175 15 0.2 0.25 0.17 0.05 0.2 0.06 <0.1 <0.05 0.2 <0.05 <0.1 <0.5 <0.05 <0.1 <0.5 <0.05 0.2

: Concentrations determined by using XRF spectrometry. : Concentrations determined by using ICP-MS.

b

na: not analysed

43

<1 3 na 74 na 103 33 na <1 3 48 18 na na na na na na na na na na na na na na na na na

<1 2 na <1 na 395 16 na <1 10 12 41 na na na na na na na na na na na na na na na na na

f o

o r p

e

r P

a

6 58 <0.1 12 <1 27 265 <0.05 179 4 84 14 0.2 0.11 0.08 <0.05 0.07 <0.05 <0.1 <0.05 <0.1 <0.05 <0.1 <0.5 <0.05 <0.1 <0.5 <0.05 <0.1

4

5

na 33 na 103 14 na 23 3 45 8 na na na na na na na na na na na na na na na na na

na 25 na 44 14 na 42 3 58 12 na na na na na na na na na na na na na na na na na

7 0.5 <0.1 32 <1 25 24 1.47 16 3 62 13 <0.1 <0.05 <0.05 <0.05 <0.05 <0.05 <0.1 <0.05 <0.1 <0.05 <0.1 <0.5 <0.05 <0.1 <0.5 <0.05 <0.1

6 0.5 <0.1 37 <1 29 26 3 17 3 64 13 0.2 <0.05 <0.05 <0.05 <0.05 <0.05 0.1 <0.05 <0.1 <0.05 <0.1 <0.5 <0.05 <0.1 <0.5 <0.05 <0.1

4 <0.2 <0.1 40 <1 29 <0.05 36 3 77 14 <0.1 <0.05 <0.05 <0.05 <0.05 <0.05 <0.1 <0.05 <0.1 <0.05 <0.1 <0.5 <0.05 <0.1 <0.5 <0.05 <0.1

Journal Pre-proof

Highlights: 

Advanced listvenitization produced by hydrothermal alteration of ultramafic rocks in Rayat ophiolite area of Iraqi Kurdistan.



Fuchsite-mineralization is dominant throughout the shear zones.



The identification of the listvenite, upgrades the broader Rayat area regarding potential epithermal

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mineralizations.

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Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Figure 15

Figure 16

Figure 17

Figure 18

Figure 19

Figure 20

Figure 21

Figure 22