Genesis of sedimentary- and vein-type magnesite deposits at Kop Mountain, NE Turkey

Turkish Journal of Earth Sciences

Turkish J Earth Sci
(2013) 22: 98-114
© TÜBİTAK
doi:10.3906/yer-1101-22

/>
Research Article

Genesis of sedimentary- and vein-type magnesite deposits at Kop Mountain, NE Turkey
1,

2

3

Selahattin KADİR *, Hasan KOLAYLI , Muhsin EREN
Eskisehir Osmangazi University, Department of Geological Engineering, TR–26480, Eskisehir, Turkey
2
Karadeniz Technical University, Department of Geological Engineering, TR–61080, Trabzon, Turkey
3
Mersin University, Department of Geological Engineering, TR–33343, Mersin, Turkey

1

Received: 24.01.2011

Accepted: 11.08.2011

Published Online: 04.01.2013

Printed: 25.01.2013

Abstract: Sedimentary- and vein-type magnesites were deposited within and on ultramafic rocks of the Kop Mountain region in
Bayburt province. In the field, magnesites are exposed along NE-SW trending normal faults and in fractures in the ultramafic rocks.
Petrographic studies reveal that magnesite is predominantly micrite, but also occurs as microsparite formed by recrystallization of
micrite. The ultramafic rocks hosting the magnesites consist of serpentinized olivine, hypersthene and diopside. Ni, Co and Ti contents
of magnesites suggest precipitation from percolating water through the serpentinized ultramafic rocks. The sedimentary- and vein-type
magnesites have different d18O and d13C values, characterizing formation under different conditions. Temperature estimates using the
average d18O values reveal precipitation from water at ~24.5°C for sedimentary magnesite and ~37.0°C for vein-type magnesite. The
d13C values of vein-type magnesites are distinctly more negative than those of sedimentary magnesites, indicating carbon isotopes
derived from predominantly decarboxylation of organic sediments in shales and carbonate dissolution. Less negative d13C values in the
sedimentary magnesite are mainly due to outgassing of mineralizing water. Our data suggest a petrogenetic model in which the surface
water percolates through the ultramafic and sedimentary rocks becoming heated by volcanics at depth and enriched in Mg+2 and light
carbon isotopes, followed by migration upward to form magnesite near the surface in ultramafic rocks as fracture-fill and as sediment
at the surface.
Key Words: Magnesite, sediment, vein, ultramafic rocks, Kop Mountain, mineralogy, and geochemistry.

1. Introduction
Magnesite (MgCO3) is a scarcer carbonate mineral than
calcite and dolomite in the world and is mainly used in the
manufacture of refractory materials. It occurs in two major
geological settings: as sediment in marine and lacustrine
environments, or within or near ultramafic complexes
(Abu-Jaber & Kimberley 1992). Both these types of
magnesite occurrence are reported in the literature from
Turkey and worldwide (e.g., Zedef et al. 2000, Melezkih
et al. 2001 for marine and lake setting; Fallick et al. 1991,
Gartzos 1990, Bashir et al. 2009, Yılmaz & Kuşcu 2007,
Horkel et al. 2009, Zedef et al. 2000 for ultramafic setting).

In the Kop Mountain region, magnesite widely occurs
in ultramafic rocks forming part of the İzmir-AnkaraErzincan suture zone. This study investigates genesis
of magnesite deposits in the Kop Mountain region and
provides information on their geological, mineralogical
and geochemical characteristics because of their economic
importance. In the region, magnesite deposits, having
a probable reserve of ~ 1,000,000 tons are mined for the
manufacture of refractory materials.
*Correspondence:

98

2. Geological setting
The eastern Pontides geographically corresponding to
the eastern Black Sea Region of Turkey, is a part of the
Alpine orogenic belt. In the eastern Pontides, ultramafic
rocks occur in the Kop Mountain range between Bayburt,
Erzincan and Erzurum cities. These ultramafic rocks
are termed the Kop ophiolite complex. The magnesite
deposits in the Kop area are hosted within ultramafic
rocks consisting of serpentinized harzburgite and dunite
cut in places by pyroxenite dykes (Figures 1, 2). The Kop
ophiolite is a part of the İzmir-Ankara-Erzincan suture
zone which records the closure of the northern branch
of Neotethys as a result of the convergence between the
Eurasia and Gondwana plates (Şengör & Yılmaz 1981). It
is widely accepted that the Neotethys began to close in the
Late Cretaceous (Yalçın & Bozkaya 2004), with subsequent
Early Tertiary continental collision occurring along the
suture zone following northward subduction of Tethyan

oceanic lithosphere (Okay & Tüysüz 1999). The age of
emplacement of ophiolites in the Pontides is assumed to
be middle Eocene (Yılmaz et al. 1997).


KADİR et al. / Turkish J Earth Sci

Figure 1. Geological map of the Kop Mountain area (a), sedimentary magnesite (b) and vein magnesite (c) in ultramafic units.

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Figure 2. Simplified general stratigraphic column section of the study area (modified from Kolaylı 1996).

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KADİR et al. / Turkish J Earth Sci

In the study area, the basement consists of Palaeozoic
Pulur metamorphic units including gneiss, amphibolite and
schist (Figure 2). These metamorphics are unconformably
overlain by Liassic volcano-sedimentary rocks of the
Hamurkesen Formation which comprises intercalations of
sandstone, claystone, marl and basalt. The Malm - Lower
Cretaceous Hozbirikyayla Formation conformably ovelies
the Hamurkesen Formation, and comprises predominantly
limestone and sandstone. The ultramafic rocks were thrust

over the Mesozoic and Palaeozoic rocks during Upper
Cretaceous to Middle Eocene time. The ultramafic rocks
are unconformably overlain by the Kaplankaya Formation
(Upper Cretaceous), consisting of limestone interbedded
with sandstone. The Tertiary units are represented by
conglomerate of the Sığırcık Formation (Eocene) and
limestone, sandstone, claystone and marl of the Göller
Formation (Miocene).
3. Methods
Thin-sections were prepared from the samples and
then examined using an optical microscope (Nikon Pol
400). Mineralogical characteristics of the samples were
determined by X-ray powder diffractometry (XRD)
(Rigaku Geigerflex) and scanning-electron microscopy
(SEM-EDX) (JEOL JSM 84A-EDX), differential thermal
analysis-thermal gravimetry (PerkinElmer - Diamond
TG/DTA thermal analyzer) and infrared spectrometry
(FT-IR) (PerkinElmer 100 FT-IR spectrometer).
Representative
magnesite,
dolomite
and
hydromagnesite-dominated bulk samples were prepared
for SEM-EDX analysis by adhering the fresh, broken
surface of each sample onto an aluminium sample holder
with double-sided tape and coating with a thin (350 Å)
gold coating using a Giko ion coater. DTA-TG curves
were obtained using a 10 mg sample of powdered claysized fraction (<2 µm) in a Pt sample holder at an average
heating rate of 10°C/min with alumina as a reference
under normal atmospheric conditions. IR spectroscopic

analysis was performed on pressed pellets of powdered
clay samples (< 2 µm) mixed with KBr; scans were made at
a 4 cm–1 resolution.
Chemical analyses of twenty-five fresh whole-rock
samples were performed at Acme Analytical Laboratories
Ltd. (Canada) using ICP-AES for major and trace elements
and ICP-MS for rare-earth elements (REE). The detection
limits for the analyses were between 0.01 and 0.1 wt% for
major elements, 0.1 and 5 ppm for trace elements, and 0.01
to 0.5 ppm for REE.
Fourteen sedimentary and seventeen vein-type
magnesite, dolomite, and hydromagnesite-bearing
samples were analyzed for stable isotopes performed in
both the Laboratory of Geochronology & Isotope (USA)
and Iso-Analytical Expertise in Stable Isotope Analysis

(UK). Oxygen isotopes calculated using a fractionation
factor of 1.0047 for CO2/magnesite produced by 100%
H3PO4 decomposition at 95°C.
4. The Kop Mountain magnesite deposits
4.1. Field description
In the field, magnesite occurs mainly in two modes:
sedimentary and as veins. The sedimentary magnesites
are characterized by their bedding character and were
observed extending over an area approximaly 300 m long
and 100 m wide trending NE–SW around Avanas village
(Figure 3a). The sedimentary magnesite includes claystone,
dolomite and silica intercalations (Figure 3b). The total
thickness of sedimentary magnesites is approximately 20
metres, with bed thickness varying from a few cm to 3

metres (Figure 3b,c). The magnesites are white to cream
in colour and show conchoidal fracturing (Figure 3d).
The magnesite sequence begins with a basal conglomerate
(Figure 3e) consisting of rock fragments from different
units including ultramafics.
In the study area, magnesite is also found as thick
veins within ultramafic rocks which were observed in
three different places closely associated with normal
faults (Figure 3a) and fractures (Figure 3f–k). This type of
magnesite occurrences gradually reduces away from the
fault zone, and disappears at a distance of approximately
2-3 km. The magnesites veins vary in thickness from
several cm to 3 m (Figure 3e–k). Vein type magnesite
also coexists with small silica nodules and thin veins.
Magnesite nodules in conchoidal form between 10 and
30 cm in diameter occur in ultramafic rocks, produced by
tectonic activity similar to that reported by Yeniyol (1982)
(Figure 3l).
5. Results
5.1. Petrography
Petrographic examination of thin-sections reveals that
both sedimentary and vein-type magnesites are made up
of predominantly dense micrite and also microsparite
(Figure 4a,b). Magnesite microsparite resulted from
partial or complete recrystallization of samples indicated
by etched boundaries with micritic areas (Figure 4c),
and contains crystals predominantly 4–6 µm across,
ranging up to 10 µm across. Recrystallization was caused
by an influx of mineralizing water into the pores. Thin
sections of the breccia, seen at the base of sedimentary

magnesites, show poor sorting and angular fragments
derived from different rocks such as limestones containing
fossils including Calpionella elliptica Cadish, Calpionella
alpina Lorenz, foraminifera (Figure 4d) from Berriasian;
Laffitteina cf. bibensis Marie (Figure 4e), Pseudosiderolites
cf. vidali Douville from the Upper Maastrichtian;
Globotruncana sp., Pithonella sp, Calcisphaerula sp. from

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Figure 3. Field photographs of magnesites. (a) sedimentary magnesite (mg) associated with a shear zone within the ultramafic
rocks (u); (b) general view of the sedimentary magnesites (mg) including claystone intercalations (arrow); (c) close view of
sedimentary magnesite (mg) including claystone (sm) intercalations; (d) a magnesite block showing conchoidal fracturing
(hammer); (e) basal breccia consisting of different rock fragments including ultramafic blocks (u); (f–k) magnesite veins (mg)
in ultramafic units (u); (l) typical magnesite block (mg) in ultramafic rocks (u).

the Upper Cretaceous; coralline algae (Figure 4e) probably
from the Tertiary; and also radiolaria and sponge spicules
(Figure 4f), silicified volcanic rocks, ultramafic rocks, and
metamorphic quartzites. The basal conglomerate includes
sandy matrix fill between grains which was later cemented
by magnesite. The host rocks (ultramafics) of magnesites
are highly to partially serpentinized dunite and harzburgite
(Figure 4g,h).

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5.2. XRD determinations
The mineralogical compositions of bulk magnesite and
associated rock samples were examined by XRD, and
semi-quantitative mineral contents are given in Table 1.
The results indicate that magnesite predominates in the
sedimentary rocks and magnesite beds include dolomite,
magnesitic dolomite, smectite and silica (quartz)
intercalations. Vein infills in highly altered ultramafics


KADİR et al. / Turkish J Earth Sci

Figure 4. Photomicrographs of magnesite and associated rocks. (a) micritic magnesite, plane-polarised light (sample: VM-40); (b)
microsparitic patches (arrow) in micritic magnesite, plane-polarised light (sample: SY); (c) mostly microsparitic magnesite, planepolarised light (SZ); (d) limestone and fossil fragments in the breccia underlying sedimentary magnesite, plane-polarised light (SZ-4);
(e) fossil fragment (red algae) and microfossils (fr: foraminifera) in limestone fragment, plane-polarized light (SZ-4); (f) microfossils in
limestone fragment. rad: radiolarite, sp: sponge spicule, plane-polarised light (SZ-4); (g) development of vein magnesite in completely
serpentinized dunite showing mesh texture, crossed polars (F-9); (h) development of magnesite vein in dense serpentinized harzburgite,
crossed polars (F-9).

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Table 1. Mineralogical compositions of magnesite and associated rocks.
Sample No

Rock type

mg

hmg

dol

srp

qtz

smc

Sedimentary
SM-1

Magnesite

+++++

SM-4

Magnesite

+++++

SM-5

Magnesite

+++++

SM-6

Magnesite

+++++

SM-7

Magnesite

+++++

SM-8

Magnesite

+++++

SM-10

Magnesite

+++++

SM-12

Magnesite

++++

+

SM/D-9

Magnesitic dolomite

++

+++

SM/D-13

Magnesitic dolomite

++

+++

SM-11

Silicate

+

acc
++++

Claystone
SM-2

Claystone

+++++

SM-3

Claystone

+++++

VZ-1

Magnesite

+++++

VZ-2

Magnesite

+++++

VB-2

Magnesite

+++++

VB-3

Magnesite

+++++

VM-30

Magnesite

+++++

VM-31

Magnesite

+++++

VM-41

Magnesite

+++++

VM-43

Magnesite

+++++

VD-31

Dolomite

acc

HM-1

Hydromagnesite

+++

++

HM-4

Hydromagnesite

++++

+

Vein

acc

+++++

Vein
VS-40

Silicate

VS-42

Silicate

+++++
+++++
Host rock

VD-31Y

Altered ultramafic rock

L-20

Altered ultramafic rock

DUM-M

Altered ultramaficrock

HM-9

Altered ultramafic rock

J-9

Altered ultramafic rock

+++

++
+++++

acc

+++++
acc

+++
+++++

mg: magnesite, hmg: hydromagnesite, dol: dolomite, srp: serpentine, qtz: quartz, smc: smectite, acc: accessory, +: relative abundance of
mineral.

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Figure 5. X-ray diffraction patterns of magnesite and host rock samples. mg: magnesite, hmg: hydromagnesite, dol:
dolomite, srp: serpentine.

consist mainly of pure magnesite; hydromagesite, silica
(quartz) and dolomite are also present. Magnesite has
sharp diagnostic basal reflections at 2.74, 2.50, 2.11, 1.94,
1.70 Å (Figure 5). Hydromagnesite was determined by
9.18, 5.79, 3.31, 2.90 Å peaks, dolomite was recognized
by its 3.69, 2.88, 2.19, 1.78 Å reflections. Serpentine was
determined by 7.30, 4.58, 3.66, 2.46, 2.54 Å reflections.
Brucite was determined by 3.14, 4.77 Å peaks. Smectite is

recognized by its 15.5 Å reflection which expands to 17
Å, and then collapsed to 10 Å after heating at 350°C and
550°C.
5.3. SEM-EDX determinations
Scanning electron microscope analyses were carried
out on vein and sedimentary magnesite, dolomite and
hydromagnesite samples. SEM images indicate that
micritic magnesite rhombs are dominant in vein samples.
The magnesite samples consist of euhedral or subhedral
crystals 2–6 µm across (Figure 6a). Sedimentary magnesite

samples consist of micritic magnesite subhedral crystals <
2 µm across coexisting with relict altered dolomite crystals
which were isomorphically converted to magnesite
(Figure 6b,c). Magnesitic dolomite samples show
subhedral dolomite crystals up to 3–7 µm across edged
with micritic magnesite crystals (Figure 6d,e). Dolomitic
samples consist of euhedral to subhedral micritic and
sparry crystals (Figure 6f–h). In samples HM-4 and HM1, hydromagnesite occurs as well-developed plates and
rosettes filling veins cross-cutting micritic hydromagnesite
(Figure 6i–k). Hydromagnesite plates exhibit subhedral
crystals up to 50 µm across and approximately 1 µm thick.
Hydromagnesite shows a platy habit (Figure 6l).
Rhombic carbonate crystals were distinguished by
EDX analyses from their strong peaks for either Ca, Mg
and C, or Mg and C, suggesting a dolomitic or magnesitic
composition. Well-developed plate and rosette structures
also show strong peaks for Mg and C, suggesting a
hydromagnesite composition.

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Figure 6. SEM images of: (a) euhedral to subhedral crystals of vein-type micritic magnesite (sample: VZ-1); (b–c) micritic magnesite
crystals with relict of dolomite (sample: SM-6, SM/D-13); (d–e) micritic magnesite crystals on dolomite (sample: SM/D-13); (f) fracture
filling of microsparitic dolomite in micritic dolomite (sample: VD-31); (g–h) euhedral sparry dolomite crystals (sample: VD-31); (i–j)
platy hydromagnesite (sample: HM-4); (k) close view of hydromagnesite displaying rosette form (sample: HM-4); (l) view of platy
hydromagnesite crystals (sample: HM-1).

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Figure 7. DTA-TG curves for magnesite (sample: VZ-1),
dolomite (sample: VD-31) and hydromagnesite (sample: HM-4).

5.4. DTA-TG analyses
DTA-TG analyses were carried out on magnesite, dolomite
and hydromagnesite samples (Figure 7). The DTA-TG
curve for magnesite has large endothermic peaks at 623°C
(weight loss: 52%) due to decomposition of MgCO3 in the
magnesite structure (Figure 7a; MacKenzie 1957; Webb
& Krüger 1970; Smykatz-Kloss 1974). Analysis of the
dolomite sample shows two main endothermic peaks at
756°C (weight loss: 23.5%) and 811°C (weight loss: 19%),
due to decomposition of MgCO3 and CaCO3, respectively,
in the dolomite structure (Figure 7b; MacKenzie 1957;

Webb & Krüger 1970; Smykatz-Kloss 1974).
The analysis of hydromagnesite-dominated samples
shows that sample HM-4 gives three main endothermic
peaks at 273°C (weight loss: 9.3%), 414°C (weight loss:
13.4%), 508 and 545°C (weight loss: 28.1%) (Figure 7c;
MacKenzie 1957; Webb & Krüger 1970; Smykatz-Kloss
1974). The first endothermic peak corresponds to the loss
of water of crystallization. The second endothermic peak
is possibly due to loss of remaining hydroxyl molecules.
The last two endothermic peaks are due to carbonate
decomposition.
5.5. Infrared spectra
The IR spectra for magnesite, dolomite and hydromagnesite
samples are given in Figure 8. The IR spectra for the

Figure 8. IR spectra for magnesite (sample: VZ-1), dolomite
(sample: VD-31) and hydromagnesite (sample: HM-4).

magnesite sample VZ-1 is characterized by a symmetrical
stretching, intense band at 1450 cm–1, and sharp bands at
881 and 749 cm–1, all related to CO3–2 anions (Figure 8a,
Van der Marel & Beutelspacher 1976). The occurrence of a
broad, intense band at 1440 cm–1, and sharp bands at 881
and 729 cm–1, is attributed to the presence of dolomite in
sample VD-31, which is distinguished from magnesite by
a shift of all bands (except 881, 1099 and 2627) to lower
frequency (Figure 8b, Van der Marel & Beutelspacher
1976).
The IR spectra for the hydromagnesite-dominated
sample HM-4 are recognized by bands at 3649, 3516,

3451, 1485, 1428, 885, 853, 791, 595, 483 cm–1 (Figure 8c).
The sharp band at 3649 cm–1 is attributed to almost free
O-H vibration. The IR spectra results are consistent with
the results of XRD, SEM-EDX, DTA-TG and chemical
analyses of the samples.

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5.6. Geochemistry
Chemical analyses were conducted on selected
sedimentary- and vein-type magnesite samples and host
rocks from the study area (Table 2). These samples are
mainly composed of variable MgO, CaO, SiO2, Al2O3, Fe2O3,
and loss on ignition (LOI) contents. The sedimentary and
vein magnesite samples are characterized by high MgO
(42.33–46.50 and 44.49–47.37%), and LOI (49.50–51.4
and 50.5–51.8%) contents, respectively. The dolomitedominated VD-31 sample is distinguished by 21.71% MgO,
29.20% CaO and 46.3% LOI. The hydromagnesite samples
are characterized by relatively lower MgO (39.83–40.68
%), and LOI (39.2–47.8%) and higher Fe2O3 (1.93–3.63)
SiO2 (8.60–15.98) contents than magnesite. The presence
of CaO associated with MgO reflects the presence of
dolomite accompanied by magnesite. Thus, the dolomitedominated VD-31 sample contained 21.71% MgO, 29.20%
CaO and 46.3% LOI.
The presence of 45.28% SiO2, 17.98% MgO, 5.74% Al2O3,
8.19% Fe2O3 and 20.3% LOI in the SM-3 claystone sample
is characterized as saponite prevalent, similar to that of the

saponites from Griffith Pass in California and Winnweiler,
Pfalz in Germany (Newman & Brown 1987). These values
reflect saponitic claystone intercalated with magnesite
and dolomite units. The siliceous bed and vein (quartz)
samples associated with magnesites are characterized by
high SiO2 (74.31% and 98.18%), respectively.
Chemical analyses of harzburgite and dunite samples
are characterized by high SiO2, MgO, Fe2O3 and LOI (Table
2). The Fe2O3 content in harzburgite (5.93%) and dunite
(8.55%) reflects the presence of hypersthene and olivine.
Nickel (max. 109.8-983, 2674 ppm), Co (max. 72.052.9, 121.1 ppm), V (max. 34-10, 66 ppm) in sedimentary
and vein-type magnesites, and serpentinized dunite and
harzburgite host rock samples respectively, reflect the
availability of ferromagnesian material originating from
serpentinized ultramafic-basement units (Table 2). Ni and
Co (positively correlated with Fe2O3 ± TiO2) are enriched in
the claystone sample intercalating sedimentary magnesite,
ranging up to 1510 ppm and 96.8 ppm, respectively (e.g.,
SM-3).
Barium and Rb are constant and scarcer in veintype magnesite than in sedimentary magnesite. Positive
correlation of Sr with dolomite content reveals that Sr is
related to Ca-bearing dolomite (e.g., samples VD-31, SM9).
REE of sedimentary and vein-type magnesites and
host rocks have parallel profiles to each other (Sun &
McDonough 1989), and, except for samples SM/D-9 and
SM-3, exhibit negative Ce and Nb anomalies, suggesting
oxidizing conditions (Figure 9; Jeans et al. 2000).
5.7. Stable isotopes
Stable-isotope values for magnesite samples are listed in
Table 3 and plotted in Figure 10. The crossplot (Figure 10)

108

shows two distinctive groups of magnesite samples: the
sedimentary and vein-type magnesites. The sedimentary
magnesites have d13C and d18O values ranging from -0.4 to
-4.9‰ PDB and from 29.4 to 34.2‰ SMOW, respectively,
whereas the vein-type magnesites have d13C values ranging
from -7.6 to -14.6‰ PDB and d18O values ranging from
23.3 to 30.7‰ SMOW. Overall, d18O values of sedimentary
magnesite samples vary in a very narrow range respect
to d13C values, and vein magnesite samples exhibit more
negative d13C values than those of the sedimentary
magnesite samples.
6. Discussion
The Kop Mountain ophiolites belong to İzmir-AnkaraErzincan suture zone which marks the closure of the
northern branch of Neotethys. In the region, magnesite
is widely exposed within the ultramafic rocks consisting
predominantly of serpentinized harzburgite. In the field,
magnesites are exposed along NE-SW trending normal
faults in the ultramafic rocks and occur either as sediment
or infill of vein-type fractures. The age of magnesite is
unclear. However, considering the ophiolite emplacement
in the region, and palaeontological data from the breccia
clasts which underlie the sedimentary magnesite, we
may estimate the age to be younger than middle Eocene,
probably Miocene. In the crossplot of d18O and d13C values
(Figure 10), stable isotope values of sedimentary magnesite
distinctly differ from the values of vein-type magnesite,
indicating formation under different conditions. Various

genetic models have been proposed to explain the
magnesite origin in ultramafic terranes. For these models,
supergene, hypogene, and combined supergene-hypogene
processes have been proposed (Frank & Fielding 2003).
Most studies favour a mechanism to explain magnesite
associated with ultramafic rocks in Alpine-orogenic
belt based on combined supergene-hypogene processes
(Fallick et al. 1991, Zedef et al. 2000, Ece et al. 2005,
Mirnejad et al. 2008). In all the models, researchers agree
that the source of magnesium was the ultramafic rocks
themselves (O’Neil & Barnes 1971; Yeniyol 1982; Zedef et
al. 2000; Mirnejad et al. 2008). In this study, this conclusion
is supported by relatively high Co, Ni and Ti contents in
the magnesites and associated sedimentary rocks (Table
2). Differences in the genetic models have been based on
various carbon sources which are summarized by Zedef
et al. (2000) as: atmospheric, decarboxylation of organic
rich sediments, thermal decarbonation of limestones,
decomposition of organic material in soil, regional
metamorphic reactions at above >300°C, volcanogenic
sources, deep-seated sources, or combinations of all of
these. In this study, the vein-type magnesites have d13C
values predominantly ranging from –9.00 to –11.23‰
PDB with two exceptions. These d13C values differ from


KADİR et al. / Turkish J Earth Sci
Table 2. Chemical compositions of magnesite and associated rocks.
Sedimentary
Magnesite

Magnesitic dolomite

Claystone

Silicate

Oxide (%)

SM-1

SM-4

SM-5

SM-6

SM-7

SM-10

SM-12

SM/D-9

SM/D-13

SM-3

SM-11

SiO2
Al2O3
ΣFe2O3
MgO
CaO
Na2O
K2O
TiO2
MnO
LOI
TOTAL
 
ppm
Ba
Co
Cs
Ga
Hf
Nb
Rb
Sn
Sr
Ta
Th
U
V
W
Zr
Y

Pb
Zn
Ni
Mo
Cu
As
Sb
La
Ce
Pr
Nd
Sm
Eu
Gd
Tb
Dy
Ho
Er
Tm
Yb
Lu 

2.06
0.16
0.54
44.63
0.91
0.08
<0.01
<0.01

0.03
50.8
99.26
 
 
 21
 1.1
 <0.1
 <0.5
 <0.1
 <0.1
 0.3
 <0.1
 64.6
 <0.1
 <0.2
 <0.1
 <8
 <0.5
 1.7
 0.7
 0.1
 4
 54.1
 <0.1
 3.4
 1.1
 <0.1
 0.4
 0.6

 0.08
 <0.3
 0.06
 0.04
 0.12
 0.03
 0.12
 0.02
 0.05
 0.01
 0.08
 0.02

0.97
0.08
0.34
45.34
1.63
0.03
<0.01
<0.01
0.02
50.8
99.26
 
 
 12
0.5 
 <0.1
<0.5 

<0.1 
<0.1 
0.2 
<0.1 
27.9 
<0.1 
<0.2 
0.2 
34 
<0.5 
1.9 
0.4 
0.1 
2 
 15.6
<0.1 
2.3 
1.3 
<0.1 
0.4 
0.5 
0.07 
0.4 
0.06 
0.02 
0.1 
0.01 
0.05 
<0.02 
0.04 

0.01 
<0.05 
<0.01 

0.45
0.06
0.12
46.50
1.25
0.03
<0.01
<0.01
<0.01
50.8
99.24
 
 
 9
<0.2 
<0.1 
<0.5 
<0.1 
<0.1 
0.3 
<0.1 
21.4 
<0.1 
<0.2 
<0.1 
15 

 <0.5
1.6 
<0.1 
<0.1 
2 
2.2 
<0.1 
0.3 
1.6 
 <0.1
0.2 
0.3 
0.04 
<0.3 
<0.05 
<0.02 
<0.05 
<0.01 
<0.05 
<0.02 
<0.03 
<0.01 
<0.05 
<0.01 

0.78
0.06
<0.04
46.25
0.56

0.06
<0.01
<0.01
<0.01
51.4
99.23
 
 
 32
0.3 
<0.1 
<0.5 
<0.1 
 0.1
0.3 
<0.1 
73.8 
<0.1 
<0.2 
<0.1 
<8 
<0.5 
1.1 
0.2 
0.1 
2 
3 
<0.1 
1.3 
1.8

<0.1 
0.2 
0.3 
0.03 
<0.3 
<0.05 
 <0.02
<0.05 
<0.01 
<0.05 
 <0.02
<0.03 
<0.01 
<0.05 
<0.01 

0.58
0.06
0.27
46.03
0.88
0.06
<0.01
<0.01
<0.01
51.3
99.24
 
 
 16

0.4 
<0.1 
<0.5 
<0.1 
 <0.1 
<0.1 
<0.1 
35.3 
<0.1 
<0.2 
<0.1 
<8 
<0.5 
0.4 
0.2 
<0.1 
2 
14.2 
<0.1 
0.9 
1.8 
<0.1 
0.2 
0.3 
0.02 
<0.3 
<0.05 
 0.02
<0.05 
0.01 

 <0.05
 <0.02
<0.03 
 <0.01
<0.05 
<0.01 

3.84
0.62
1.05
42.33
1.76
0.05
0.07
0.02
0.02
49.5
99.30
 
 
19 
7.2 
0.1 
0.6 
0.2 
0.3 
2.1 
<0.1 
 51.1
<0.1 

0.3 
<0.1 
19 
<0.5 
4.4 
0.9 
0.4 
3 
88.4 
0.3 
7.2 
2.6 
<0.1 
0.6 
0.3 
0.18 
0.7 
0.16 
0.04 
0.14 
0.03 
0.12 
0.03 
0.08 
0.02 
0.09 
0.01 

0.94
0.11

0.17
44.11
3.57
0.02
<0.01
<0.01
<0.01
50.3
99.27
 
 
9 
1.5 
<0.1 
<0.5 
<0.1 
<0.1 
0.4 
<0.1 
52 
<0.1 
 <0.2
<0.1 
<8 
 <0.5
1.3 
0.2 
0.2 
2 
23.1 

<0.1 
1.9 
1.2 
 <0.1
0.2 
0.3 
0.03 
<0.3 
<0.05 
 <0.02
<0.05 
<0.01 
<0.05 
<0.02 
<0.03 
<0.01 
<0.05 
<0.01 

4.35
1.09
1.00
29.26
17.35
0.06
0.13
0.04
0.03
46.2
99.49

 
 
28 
8 
0.3 
1.4 
0.2 
 0.5
4.5 
<0.1 
206.8 
<0.1 
0.4 
0.1 
22 
 <0.5
7.2 
1.9 
0.4 
5 
109.8 
0.2 
6.1 
3.8 
 <0.1
1.6 
0.3 
0.38 
1.5 
0.30 

0.07 
 0.33
0.05 
 0.29
0.06 
0.18 
 0.03
 0.15
 0.03

1.66
0.30
0.26
31.46
17.52
0.04
0.03
0.01
0.02
48.1
99.45

45.28
5.74
8.19
17.98
1.29
0.09
0.25
0.17

0.04
20.3
99.66
 
 
 135
 96.8
 0.9
 6.1
 0.7
 1.8
8.8 
<0.1 
39.9 
0.1 
1.6 
0.4 
139 
<0.5 
21.8 
5.1 
1.7 
30 
1510
0.3 
81.1 
4.4 
<0.1 
3.9 
7.5 

0.98 
4 
0.78 
0.23 
0.87 
0.15 
0.89 
0.19 
0.54 
0.09 
0.52 
0.08 

74.31
0.18
0.56
10.97
0.42
0.06
0.02
<0.01
<0.01
13.3
99.81
 
 
45 
1 
<0.1 
0.7 

<0.1 
0.2 
0.4 
<0.1 
18.2 
<0.1 
<0.2 
0.3 
11 
<0.5 
2.2 
0.2 
1 
27 
11.8 
3.8 
4 
1 
<0.1 
0.2 
0.3 
0.04 
<0.3 
<0.05 
<0.02 
<0.05 
<0.01 
<0.05 
<0.02 
<0.03 

<0.01 
<0.05 
<0.01 

16
2
0.1
<0.5
<0.1
0.2
1.4
<1
209
<0.1
0.2
0.1
11
<0.5
3.9
0.6
0.3
3
34.4
<0.1
3.2
1.4
<0.1
0.6
1.3
0.14 

0.6
0.09 
0.03
0.11
0.02
0.08
0.02
0.05
0.01
0.06
0.01

109


KADİR et al. / Turkish J Earth Sci
Table 2. Continued.
Vein
Magnesite
Oxide (%)

Dolomite

Hydromagnesite

Silicate

VM-30

VZ-1

VZ-2

VZ-3

VB-3

VD-31

HM-1

HM-4

VS-40

VS-42

VS-43A

SiO2
Al2O3
ΣFe2O3
MgO
CaO
Na2O
K2O
TiO2
MnO
LOI
TOTAL

0.79
<0.01
0.27
46.89
0.67
<0.01
<0.01
<0.01
0.05
50.5
99.24

0.36
0.03
0.21
46.69
0.71
<0.01
<0.01
<0.01
<0.01
51.2
99.23

0.14
0.02
0.15
46.20
1.50

<0.01
<0.01
<0.01
<0.01
51.2
99.23

0.14
0.02
0.11
47.37
0.62
<0.01
<0.01
<0.01
0.09
50.8
99.22

0.54
0.03
1.53
44.49
0.77
<0.01
0.01
<0.01
0.03
51.8
99.27

1.31
0.01
0.25
21.71
29.20
0.06
<0.01
<0.01
0.69
46.3
99.57

15.98
0.09
3.63
39.83
0.16
<0.01
<0.01
<0.01
0.06
39.2
99.34

8.60
0.07
1.93
40.68
0.10

<0.01
<0.01
<0.01
0.03
47.8
99.33

95.45
0.03
0.25
1.59
0.13
<0.01
0.02
<0.01
<0.01
2.5
99.97

98.18
0.05
0.33
0.43
0.02
<0.01
0.01
<0.01
<0.01
1.0
99.99

97.67
0.05
0.58
0.37
0.02
<0.01
0.01
<0.01
<0.01
1.3
99.99

 ppm
Ba
Co
Cs
Ga
Hf
Nb
Rb
Sn
Sr
Ta
Th
U
V
W
Zr
Y

Pb
Zn
Ni
Mo
Cu
As
Sb
La
Ce
Pr
Nd
Sm
Eu
Gd
Tb
Dy
Ho
Er
Tm
Yb
Lu 

 
 3
6.7 
<0.1 
<0.5 
 0.1
<0.1 
<0.1 

<0.1 
4.4 
<0.1
<0.2
<0.1 
<8 
<0.5 
1.1 
<0.1 
<0.1 
1 
80.9 
<0.1
0.7 
1.1 
<0.1 
<0.1 
<0.1 
<0.2 
 <0.3
<0.05 
 <0.02
<0.05 
<0.01 
<0.05 
<0.02 
<0.03 
<0.01 
<0.05 
<0.01 

3
2.6
<0.1
<0.5
0.1
0.2
<0.1
<1
5.3
<0.1
<0.2
<0.1
<8
<0.5
8.5
<0.1
<0.1
<1
30.2
<0.1
0.1
0.9
<0.1
<0.1
0.1
<0.02
<0.3
<0.05
<0.02

<0.05
<0.01
<0.05
<0.02
<0.03
<0.01
<0.05
<0.01

3
1.5
<0.1
<0.5
<0.1
<0.1
<0.1
<1
38.2
<0.1
<0.2
<0.1
<8
<0.5
5.7
<0.1
<0.1
<1
18
<0.1
0.2

1.6
<0.1
<0.1
<0.1
<0.02
<0.3
<0.05
<0.02
<0.05
<0.01
<0.05
<0.02
<0.03
<0.01
0.06
<0.01

 3
 23.7
 <0.1
 <0.5
 <0.1
 <0.1
 <0.1
 <0.1
 17.4
<0.1
<0.2
 <0.1
 <8

 <0.5
 0.8
 <0.1
 5
 5
 152.3
 <0.1
 14.9
 1.9
 <0.1
 <0.1
 <0.1
 <0.2
 <0.3
<0.05 
<0.02 
<0.05 
<0.01 
<0.05 
<0.02 
<0.03 
<0.01 
<0.05 
<0.01 

2
23.2
<0.1
<0.5
<0.1

<0.1
0.2
<1
4.8
<0.1
<0.2
<0.1
<8
<0.5
3
<0.1
<0.1
4
187
<0.1
0.5
0.8
<0.1
0.1
0.1
<0.02
<0.3
<0.05
<0.02
<0.05
<0.01
<0.05
<0.02
<0.03
<0.01

<0.05
<0.01

 
2 
9.4 
<0.1 
0.5 
<0.1 
<0.1 
<0.1 
<0.1 
640.8 
<0.1
<0.2
<0.1 
<8 
<0.5 
0.5 
<0.1 
0.1 
2 
55.8 
0.2 
7.6 
3.1 
<0.1 
<0.1 
<0.1 
<0.2 

 <0.3
<0.05 
<0.02 
<0.05 
<0.01 
<0.05 
<0.02 
<0.03 
<0.01 
<0.05 
<0.01 

<1
52.9
<0.1
<0.5
<0.1
<0.1
<0.1
<1
<0.5
<0.1
<0.2
<0.1
10
<0.5
3
<0.1
<0.1
11

983
<0.1
5.7
2.2
<0.1
<0.1
<0.1
<0.02
<0.3
<0.05
<0.02
<0.05
<0.01
<0.05
<0.02
<0.03
<0.01
<0.05
<0.01

1
21.3
<0.1
<0.5
<0.1
<0.1
0.2
<1
1.4
<0.1

<0.2
<0.1
<8
<0.5
3.4
<0.1
0.2
6
359
<0.1
2.9
2.7
<0.1
0.3
0.2
<0.02
<0.3
<0.05
<0.02
<0.05
<0.01
<0.04
<0.02
<0.03
<0.01
<0.05
<0.01

 
1 

0.6 
0.3 
<0.5 
<0.1 
<0.1 
1
<0.1 
1.1 
<0.1
<0.2
<0.1 
<8 
 <0.5
<0.1 
<0.1 
<0.1 
<1 
104.3 
1.7 
2.4 
<0.5
 <0.1
 <0.1
 <0.1
<0.2 
 <0.3
<0.05 
 <0.02
<0.05 
<0.01 

<0.05 
<0.02 
<0.03 
<0.01 
<0.05 
<0.01 

 
2 
0.6 
0.2 
<0.5 
<0.1 
<0.1 
 0.6
<0.1 
0.6 
<0.1
<0.2
<0.1 
<8 
<0.5 
0.4 
<0.1 
<0.1 
<1 
27.6 
2.5 
2.7 
<0.5 

<0.1 
<0.1 
<0.1 
<0.2 
 <0.3
<0.05 
<0.02 
<0.05 
<0.01 
<0.05 
<0.02 
<0.03 
<0.01 
<0.05 
<0.01 

 
3 
0.7 
0.2 
<0.5 
<0.1 
<0.1 
0.6 
<0.1 
1.2 
<0.1
<0.2
<0.1 
<8 

<0.5 
1.7 
<0.1 
0.2 
1 
27.7 
 5
6.2 
<0.5 
<0.1 
<0.1 
<0.1 
<0.2 
 <0.3
<0.05 
 <0.02
<0.05 
<0.01 
<0.05 
<0.02 
<0.03 
<0.01 
<0.05 
<0.01 

110


KADİR et al. / Turkish J Earth Sci
Table 2. Continued.

Dunite
Oxide (%)
SiO2
Al2O3
ΣFe2O3
MgO
CaO
Na2O
K2O
TiO2
MnO
LOI
TOTAL
 ppm
Ba
Co
Cs
Ga
Hf
Nb
Rb
Sn
Sr
Ta
Th
U
V
W
Zr

Y
Pb
Zn
Ni
Mo
Cu
As
Sb
La
Ce
Pr
Nd
Sm
Eu
Gd
Tb
Dy
Ho
Er
Tm
Yb
Lu 

Host rock
Harzburgite

F-9

CT-37

VD-31Y

43.23
2.65
8.55
33.02
2.74
0.06
<0.01
0.08
0.12
8.4
98.86

36.14
0.12
5.93
40.89
<0.01
<0.01
<0.01
<0.01
0.09
15.5
98.71

38.59
0.60
7.72
31.89

2.28
0.04
0.02
0.01
0.09
17.3
99.47

8
99
0.3
2.7
<0.1
<0.1
0.2
<1
14.8
<0.1
<0.2
<0.1
66
1.1
0.9
2.2
<0.1
22
1863
0.5
23.8
<0.5

<0.1
<0.1
<0.1
<0.02
<0.3
0.12
0.05
0.21
0.05
0.32
0.08
0.27
0.04
0.26
0.04

<1
102
0.6
<0.5
<0.1
<0.1
0.2
<1
<0.5
<0.1
<0.2
<0.1
<8
<0.5

0.2
<0.1
0.6
17
2454
<0.1
3.7
<0.5
<0.1
<0.1
<0.1
<0.02
<0.3
<0.05
<0.02
<0.05
<0.01
<0.05
<0.02
<0.03
<0.01
<0.05
<0.01

5
121.1
0.4
0.9
<0.1
<0.1

0.6
<1
35.2
<0.1
<0.2
<0.1
33
1.1
1.8
<0.1
0.6
21
2674
0.2
9.1
1.5
<0.1
0.1
<0.1
<0.02
<0.3
<0.05
<0.02
<0.05
<0.01
<0.05
<0.02
<0.03
<0.01
<0.05

<0.01

Figure 9. Chondrite-normalised REE patterns for sedimenary
and vein magnesites and related ultramafics (Sun & McDonough
1989).

deep-seated or mantle sources of CO2 (ranging from –4
to –8‰ PDB from Deines 1980) and indicate a derivation
predominantly from the decarboxylation of organic-rich
Liassic and Palaeozoic sediments beneath the obducted
ultramafic rocks with some contribution from the thermal
decarbonation of limestones (Fallick et al. 1991; Zedef
et al. 2000; Ece et al. 2005). In contrast, the sedimentary
magnesites exhibit considerably less negative d13C values
averaging -3.0 ‰ PDB which are due mainly to outgassing
of the mineralizing fluid with some involvement from
atmospheric carbon. These d13C values are coincident
with values of sedimentary magnesite from the West
Carpathians of Slovakia (Ilavsky et al. 1991), but differ
from evaporatic lacustrine and marine sedimentary
magnesites (d13C > 0‰ PDB; Melezhik et al. 2001; Zedef
et al. 2000).
As temperature is the main factor controlling the
oxygen isotope fractionation, water temperature can be
estimated using the following Aharon (1988) equation:
103Inα = d18Om – d18Ow= A (106 T–2) + B
where 103 Inα is the per mil fractionation between
magnesite (m) and water (w), T is temperature in Kelvin,
A and B are constants (A= 3.53 and B= –3.58 for magnesite
from Aharon 1988). The estimated temperatures for water

from which magnesite has been precipitated are ~24.5°C
for the sedimentary magnesite and ~37.2oC for the vein
magnesite based on the average d18O values (31.3 ‰
SMOW for sedimentary and 28.1 ‰ SMOW for vein)
and assumption of d18Ow (–5‰ SMOW from Zedef et al.
2000). These temperatures indicate low and moderatetemperature magnesites formed under surface or nearsurface conditions, respectively.
In the eastern Pontides, the emplacement of ultramafic
rocks took place during Upper Cretaceous - Middle
Eocene time under a compressional tectonic regime.
Later, after the Middle Eocene the area was subjected to
extensional tectonic movements associated with volcanic
activity. The extensional tectonic movements produced
vertical faulting and fracturing. The isotopic data suggest

111


KADİR et al. / Turkish J Earth Sci
Table 3. O- and C- isotopic compositions of magnesite and associated rocks.
Sample No

d13C (VPDB)

d18O (VSMOW)

Sample No

d13C (VPDB)

Sedimentary-type

Vein-type

Magnesite

Magnesite

d18O (VSMOW)

SM-1

-4.0

30.9

VM-3

-7.6

23.3

SM-4

-4.9

32.1

VM-30

-11.4

30.1

SM-5

-2.6

34.2

VM-31

-14.6

30.7

SM-6

-3.7

29.4

VM-41

-7.9

30.6

SM-7

-2.8

31.7

VM-43

-9.3

27.6

SM-10

0.4

32.3

VM-53

-9.0

28.3

SM-12

-3.6

30.7

VB-3

-9.4

27.4

SM-31

-2.4

31.5

VZ-1

-9.7

27.3

SM-32

-2.2

30.8

VZ-2

-9.3

26.7

SM-33

-2.9

31.0

VM-1

-11.2

28.2

SM-34

-3.0

31.6

VM-2

-11.2

28.2

SM-35

-3.5

30.1

VM-3a

-11.2

27.9

avg

-3.0

31.3

VM-4

-11.2

28.3

VM-6

-11.2

28.2

avg

-10.3

28.1

Magnesitic dolomite
SM/D-9

-4.1

28.3

SM/D-13

-3.6

27.7

Dolomite
VD-31

-10.8

23.4

Hydromagnesite

that surface water percolated through faults and fractures
in ultramafic rocks and organic-rich sediments enabling
the percolating water to pick up Mg+2, Ca+2, OH–, Si+4
from ultramafic rocks by dissolution and carbon from
organic-rich sediments by decarboxylation of organic
material. Some carbon isotopes may have been supplied
by dissolution of limestones. Volcanic activity probably
provided additional heat for the dissolution of limestones
and decarboxylation. These fluids then ascended and
became more alkaline solutions with high pH (>11; Ece et
al. 2005) values. From the supersaturated ascending fluids,

magnesite precipitated in the fractures within ultramafic
rocks at depths close to the surface, probably several
hundred metres down. The estimated depth is based on
the surface temperature (~ 20°C) and average d18O value
of vein-type magnesite. We also assume that sedimentary

112

HM-1

-4.5

25.3

HM-4

-4.4

25.4

magnesite also precipitated from same supersaturated
fluids under surface conditions in ponded water because
of its very limited extent. The pressure release under
surface conditions caused outgassing of CO2 producing
rapid precipitation of cryptocrystalline magnesite.
7. Conclusion
Magnesite in the Kop Mountain region shows two main
modes of occurrence as sedimentary and vein deposits.
Magnesite samples are predominantly micrite which has
been partly or completely recrystallized to microsparite.

The sedimentary and vein magnesites exhibit distinctly
different d18O and d13C values, indicating formation
under different conditions. Using average d18O values, the
estimated water temperatures are 24.5°C for sedimentary
magnesites and 37°C for vein magnesites, indicating


KADİR et al. / Turkish J Earth Sci

mineralizing water. Co, Ni and Ti contents of magnesite
and associated rocks indicate that Mg was derived from
serpentinized ultramafic rocks. The suggested mechanism
involves downward migration of surface water through
the ultramafic rocks and organic-rich sediments, followed
by ascent of the percolating water, from which magnesite
precipitated as infill of vein-type fractures and sediment at
the surface.

Figure 10. A crossplot of stable isotope values of two types of
magnesite.

low and moderate temperature magnesites, respectively.
The d13C values of vein magnesites indicate derivation
predominantly by decarboxylation in organic-rich
shales. The d13C values of sedimentary magnesite show
depletion in light isotopes mainly due to outgassing of

Acknowledgement
The authors are grateful to Prof. Dr. Nurdan İnan and
Prof. Dr. Kemal Taslı (Mersin University) for fossil

identifications. Appreciation is extended to Dr. Güneş
Kürkçüoğlu and Dr. Okan Z. Yeşilel (Eskisehir Osmangazi
University) for conducting the IR and DTA-TG analyses,
respectively. The authors are grateful to anonymous
reviewers for their extremely careful and constructive
reviews, which significantly improved the quality of the
paper. We are also grateful to Prof. Dr. İlkay Kuşçu and
Prof. Dr. Erdin Bozkurt for their insightful editorial
comments and suggestions.

References
Abu-jaber, N. & Kimberley, M. 1992. Origin of ultramafic-hosted
vein magnesite deposits. Ore Geology Reviews 7, 155–191.
Aharon, P. 1988. A stable isotope study of magnesite from the Rum
Jungle Uranium field, Australia: implications for the origin of
strata-bound massive magnesite. Chemical Geology 69, 127–
145.
Bashir, E., Naseem, S., Akhtar, T. & Shireen, K. 2009. Characteriscs of
ultramafic rocks and associated magnesite deposits, Nal Area,
Khuzdar, Baluchistan, Pakistan. Journal of Geology and Mining
Research 1, 034–041.
Ece, Ö.I., Matsubaya, O. & Çoban, F. 2005. Genesis of hydrothermal
stockwork-type magnesite deposits associated with ophiolite
complexes in the Kütahya-Eskişehir region, Turkey. Neues
Jahrbuch für Mineralogie- Abhandlungen 181/2, 191–205.
Deines, P. 1980. The carbon isotopic composition of diamonds:
relationship to diamond shape, color, occurrence and vapor
composition. Geochim. Et Cosmochim. Acta 44, 943–961.
Fallick, A.E., Ilich, M. & Russell, M.J. 1991. A stable isotope study
of the magnesite deposits associated with the Alpine-type

ultramafic rocks of Yugoslavia. Economic Geology 85, 847–861.
Frank, T.D. & Fielding, C.R. 2003. Marine origin for Precambrian,
carbonate-hosted magnesite. Geology 31, 1101–1104.
Gartzos, E. 1990. Carbon and oxygen istotope constaints on the origin
of magnesite deposits, North Evia (Greece). Schweizerische
Mineralogische und Petrographische Mitteilungen 70, 67–72.
Horkel, K., Ebner, F. & Spötl, CH. 2009. Stable isotopic composition
of cryptocrystalline magnesite from deposits in Turkey and
Austria. − EGU General Assembly Geophysical Research
Abstracts, v. 11. EGU 2009-11881.

Ilavsky, J., Turan, J. & Turanova, L. 1991. Magnesite deposits and
occurrences in the West Carpathians of Czechoslovakia. Ore
Geology Reviews, 6, 537–561.
Jeans, C.V., Wray, D.S., Merriman, R.J. & Fisher, M.J. 2000.
Volcanogenic clays in Jurassic and Cretaceous strata of England
and the North Sea Basin. Clay Minerals 35, 25–55.
Kolaylı, H. 1996. Kop Dağları (Erzincan, Erzurum, Bayburt)
Ultramafik ve Mafik Kayaçlarının Jeolojik, Petrolojik ve
Metalojenik İncelemesi [Geological, Petrological and Metalogenic
Investigations of Ultramafic and Mafic Rocks of Kop Mountains
(Erzincan-Erzurum-Bayburt)]. PhD Thesis, Karadeniz
Technical University, 282 p (in Turkish with English abstract,
unpublished)
MacKenzie, R.C. 1957. The differential thermal investigation of clays.
Mineralogical Society, London, 456 pp.
Melezkih, V.A., Fallick, A.E., Medvedev, P.V. & Makarikhin, V.V.
2001. Palaeoproterozoic magnesite: lithological and isotopic
evidence for playa/sabkha environments. Sedimentology 48,
379–397.

Mirnejad, H., Ebrahim-Nasrabadi, E., Lalonde, A.E. & Taylor, B.E.
2008. Mineralogy, stable isotope geochemistry, and paragenesis
of magnesite deposits from the ophiolite belt of eastern Iran.
Economic Geology 103, 1703–1713.
Newman, A.C.D. & Brown, G. 1987. The chemical constitution of
clays. In: Newman A.C.D. (ed), Chemistry of Clays and Clay
Minerals. Mineralogical Society Monograph 6, 1–128.
Okay, A.I. & Tüysüz, O. 1999. Tethyan sutures of northern Turkey.
Geological Society, London, Special Publication 156, 475–515.

113


KADİR et al. / Turkish J Earth Sci
O’neil, J.R. & Barnes, I. 1971. C13 and O18 compositions in some freshwater carbonates associated with ultramafic rocks: Western
United States. Geochimica et Cosmochimica Acta 35, 687–697.

Yalçın, H. & Bozkaya, O. 2004. Ultramafic-rock-hosted vein sepiolite
occurrences in the Ankara ophiolitic melange, Central
Anatolia, Turkey. Clays and Clay Minerals 52, 227–239.

Şengör, A.M.C. & Yılmaz, Y. 1981. Tethyan evolution of Turkey: A
plate tectonic approach. Tectonophysics 75, 181–241.

Yeniyol, M. 1982. Yunak (Konya) magnezitlerinin oluşum sorunları,
değerlendirilmeleri ve yöre kayaçlarının petrojenezi. İstanbul
Yerbilimleri 3, 21–51.

Smykatz-Kloss, W. 1974. Differential Thermal Analysis, Application
and Results in Mineralogy. Springer-Verlag, Berlin, 185 pp.

Sun, S.S. & McDonough, W.F. 1989. Chemical and isotope systematics
of oceanic basalts; implication for mantle compositions and
processes. In: Saunders, A.D. & Norry, M.J. (eds), Magmatism
in the ocean basins. Geological Society Special Publications, 42,
313–345.
Van Der Marel, H.W. & Beutelspacher, H. 1976. Atlas of IR
Spectroscopy of Clay Minerals and Their Admixtures. Elsevier,
Amsterdam. 396 pp.
Webb, T.L. & Krüger, J.E. 1970. Carbonate. In: MacKenzie, R.C. (ed),
Differential Thermal Analysis, volume 1, fundamental aspects.
Academic Press, London and New York, 303–341.

114

Yılmaz, Y., Tüysüz, O., Yiğitbaş, E., Genç, Ş.C. & Şengör, A.M.C. 1997.
Geology and tectonic evolution of the Pontides. In: Robinson,
A.G. (ed), Regional and petroleum geology of the Black Sea
and surrounding region. American Association of Petroleum
Geologists Memoir 68, Tulsa, Oklahoma,183–226.
Yılmaz, A. & Kuşcu, M. 2007. Süleymaniye (Mihalıcçık–Eskişehir)
bölgesindeki manyezitlerin jeolojisi ve jeokimyasal özellikleri.
Türkiye Jeoloji Bülteni 50, 95–107.
Zedef, V., Russell, M.J., Fallick, A.E. & Hall, A.J. 2000. Genesis of vein
stockwork and sedimentary magnesite and hydromagnesite
deposits in the ultramafic terranes of southwestern Turkey: A
stable isotope study. Economic Geology 95, 429–446.