2021 | 74/2 | 287–303 | 11 Figs. | 5 Tabs. | www.geologia-croatica.hr Journal of the Croatian Geological Survey and the Croatian Geological Society 1. INTRODUCTION Manganese deposits in Turkey are divided into four main groups by noting sources, tectonic environments, and structural features (ÖZTÜRK, 1993). These are; 1. Hydrothermal and hydrogenous manganese deposits within radiolarite cherts, 2. Diagenetic de- posits related to black shales within Lower Cretaceous carbon- ates, 3. Hydrothermal deposits within volcano-sedimentary and 4. Sedimentary-derived deposits within Oligocene sediments. Many manganese formations are observed along a line from west to east in Yozgat province. Most of these are emplaced within ophiolitic units widely observed in the region and are man- ganese-ferromanganese deposits interlayered with radiolarites. Though some deposits were determined to have very high grades (up to 69.91%), they remain short-term operations due to low re- serves. While Si values reach up to 40% in some regions, the Fe content values reach up to 29% (ÖKSÜZ 2011a,b; ÖKSÜZ & OKUYUCU, 2014; ÖKSÜZ, 2018; ÖKSÜZ et al., 2021). The ge- ological, mineralogical, and geochemical assessments of these formations have been the topic of many studies (ÖKSÜZ, 2011a,b; ÖKSÜZ & OKUYUCU, 2014; ÖKSÜZ, 2018; ÖKSÜZ et al., 2021). In those studies, it was determined that Yozgat manganese ­deposits­have­three­different­origins­of­hydrothermal,­hydro­ genous, and detrital sources. The topic of the study is the ferromanganese mineralization observed­in­the­Eğerci­region,­which­was­observed­to­be­differ- ent from other mineralization in the Yozgat region. This ferro- manganese deposit in the region was selected as the research topic as it has not appeared in any previous studies. The basic aims of the­study­were­to­define­the­geology­of­the­region,­the­ore­para­ Genesis of Ferromanganese Deposits from the Central Anatolian Province, Yozgat-Aşağı Eğerci Village-TURKEY: Geochemical Properties and Fluid Inclusions Nursel Öksüz1,* and Sümeyra Kaya2 1 Bozok University, Faculty of Engineering & Architecture, Department of Geological Engineering, 66100 Yozgat, Turkey; (corresponding author: nursel.oksuz@gmail.com) 2 Bozok University, Graduate Education Institute, 66100 Yozgat, Turkey doi: 10.4154/gc.2021.20 Abstract Eğerci village is located 16 km southwest of Yerköy (Yozgat) area which has a ferromanganese deposit that formed at the contact between basalt and limestone and shows that a banded stock- work structure occurs occasionally within the limestone. The mineralization consists of pyrolu- site, goethite, and ramsdellite, together with a lesser quantity of magnetite. Gangue minerals are determined as calcite and quartz. REE data from the mineral samples demonstrate a range from 2.70 - 63.70 ppm and the average value is 28.00. These results permit a comparison to be made with mineralization in hydrothermal deposits. Moreover, mineral samples show a positive Eu anomaly 0.88-48.10 ppm (ave. 9.94 ppm). The Ce anomaly values vary between 0.02 and 0.88 ppm (ave. 0.58 ppm). It is possible that the mineralization may be affected by the mixing of sea- water and hydrothermal fluids. The value of the positive Eu anomaly is evidence of modern oce- anic hydrothermal manganese deposits. Insight of previous fluid inclusion, studies can be eas- ily inferred that mineralization can occur at three different stages. The temperature of the first stage ranged from 338 oC to 428 oC and other stages vary from 269 oC - 317 oC and 143 oC - 236 oC, respectively. As a comparison, calculated salinity is higher in Type I fluid inclusions (1.9-14.7 wt.% NaCl equiv.) than Type II and III fluid inclusions (1.9-5.1 wt.%NaCl equiv.) It is possible that the mineralization was formed by the mixing of magmatic and meteoric waters. genesis,­wall­rocks,­the­sources­of­different­hydrothermal­fluids­ in­the­mineralization­with­ore­REE­geochemistry,­and­fluid­in- clusion studies and to determine a mineralization model for ore deposits in the region. 2. GEOLOGICAL SETTING 2.1. Regional Geology The manganese mineralization which forms the topic of the study is­observed­in­Aşağı­Eğerci­village­located­16­km­southwest­of­ Yerköy (YOZGAT) county and is situated within one of the most important massifs in Turkey of the Central Anatolian massif. The oldest­unit­outcropping­in­the­region­is­the­Paleozoic­Bozçaldağ­ Formation (Fig. 1). The unit named by SEYMEN (1982) com- prises grey coloured, mostly coarse calcite crystal-rich, modera- tely-thick bedded marbles, and massive marbles. The massive marbles­are­observed­in­a­very­small­area­south­of­Hacılı­village­ in the study area and are cut by an Upper Cretaceous Central Anatolian­granite­(AKÇAY­et­al.,­2007).­The­Eocene­Boğazköy­ Formation (ÖZCAN et al., 1980) transgressively overlies intru- sives in some regions and older units above an angular uncon- formity in other regions in the study area and close surroundings. The unit has volcanic interlayers and comprises sandstone, silt- stone, some pebblestone, mudstone, and limestone. This forma- tion is divided into three members of the ‘limestone member’ comprising sandy-silty limestone and massive limestone contain- ing­nummulites,­corals­and­gastropod­fossils,­the­‘Alimpınar­vol- canic member’ comprising basalt and basaltic pyroclastic rocks, and­the­‘dacite­member’­comprising­dominantly­dacitic­tuffs­with­ occasional dacitic and rhyolitic rocks (ÖZCAN et al., 1980). The dacite member is not observed in the study area. These three Article history: Manuscript received May 20, 2021 Revised manuscript accepted September 10, 2021 Available online October 27, 2021 Keywords: Ferromanganese, rare earth elements, hydrothermal, fluid inclusions, Yozgat (TURKEY) G eo lo gi a C ro at ic a 288 Geologia Croatica 74/3 members­identified­in­the­formation­have­both­lateral­and­verti- cal transitions with each other. Additionally, the basal structures observed­in­the­Alimpınar­volcanic­member­indicate­submarine­ volcanism. The unit is generally observed in the north-northwest and­southeast­regions­around­Aşağı­Eğerci­village.­The­Oligo- cene­İncik­Formation­(OKTAY,­1981),­is­distinguished­by­domi- nant pebblestone, sandstone, and mudstone lithologies and formed in a terrestrial environment, while Middle Miocene-Pli- ocene­lacustrine­and­terrestrial­fluvial­sediments­unconformably­ overlie all units. The youngest unit in the region is the Quaternary alluvium (KETIN, 1955; AKÇAY et al., 2007). In­the­study­area,­the­effects­are­observed­of­the­Laramian­ stage of Alpine orogenesis on the intense deformation of central Anatolia and the Taurus (KETIN, 1966). Magmatism covering large areas of the region occurred as plutonic activity within crys- talline massifs, and submarine volcanism in the Upper Creta- ceous and Middle Eocene periods. Middle Eocene units represent rocks developed in shallow marine and volcanic facies. In the Lower-Middle Eocene period, the sea level was higher than in the Cretaceous period. Towards the end of the Middle Eocene, the sea gradually began to retreat, lagoons formed, and gypsum and clayey marls formed toward the end of the Middle Eocene. At the end of the Middle Eocene, the sea regressed further and at the same time uplift and erosion occurred, with red conglomer- itic units forming in the Oligocene. During the Oligocene, the sea regressed further and lagoons formed. At the end of the Oligo- cene, occasional fresh and saltwater lakes remained while the sea was fully regressed (KETIN, 1955). Volcanic activity in younger cycles was not observed in the study area (KETIN, 1955). Figure 1. Location and geology map of the study area (modified by AKCAY et al. 2007). G eologia C roatica 289Öksüz and Kaya: Genesis of Ferromanganese Deposits from the Central Anatolian Province, Yozgat-Aşağı Eğerci Village-TURKEY ... 3. SAMPLING AND ANALYTICAL METHODS A total of 40 ore samples were taken systematically from the fer- romanganese mineralization observed in the study area. These samples were separated for geochemical analysis, polished sec- tions,­and­fluid­inclusion­studies.­Sample­powders­under­200­ mesh were analyzed at the General Directorate of Mineral Re- search and Exploration (MTA) in Turkey. Major oxide and trace element contents were determined with ICP-ES and REE’s were analyzed with the ICP-MS method. Results of the analyses are given in Tables 1 to 3. Polished sections were prepared from 15 samples by the same unit. The polished samples were investi- gated­with­a­reflected­light­Leica­microscope­in­Bozok­Univer- sity Laboratory. For accuracy of ore paragenesis, 15 samples had XRD analysis performed in the Bozok University Science and Technology Application and Research Centre (BILTEM). For­fluid­inclusion­analysis,­quartz­and­calcite­samples­ob- served as veins were examined in mineralized samples from the study­area.­A­total­of­4­samples­had­fluid­inclusion­studies­per- formed. Measurements were performed microthermometrically on double-sided polished sections, using a Linkam THMG-600 heating and cooling stage mounted on an Olympus BX51 micro- scope­in­the­Recep­Tayyip­Erdoğan­University,­Department­of­ Geological­Engineering.­The­equipment­was­suitable­for­micro- thermometric measurements from -196 to 600 °C. The Link- sys-32 DV program was used for measurements with 0.1 °C sen- sitivity and repeated measurements were shown to have an accuracy of ±0.2 °C for freezing and ±1 °C for heating experi- ments. 4. GEOLOGY OF MINERALIZATION The­Boğazköy­Formation­observed­in­the­region­comprises­vol- canic interlayers, sandstone, siltstone, and lesser amounts of peb- ble stone, mudstone, and limestone (ÖZCAN et al., 1980). At the base­of­the­unit,­poorly­defined­beds­of­­grey­and­occasionally­ red coloured pebblestone and sandstone occur. Above these, there are coal interlayers, light grey in colour, parallel bedded, graded, well-consolidated sandstones and siltstones, and very fine­grained­pebblestones.­The­Eocene­Boğazköy­Formation­is­ divided­into­three­members;­the­‘limestone­member’,­‘Alimpınar­ volcanic member’ and ‘dacite member’. The ‘limestone member’ is commonly observed in the study area and comprises coral, gastropod, and lamellibranchs, grey, moderately-thickly bedded, sandy-silty limestone, and massive limestones (Fig. 2a-c). The unit is widely observed in the region and contains banded and stockwork ferromanganese formations in the study area (Fig. 2c, d-f). The­Alimpınar­volcanic­member­comprises­basalt­and­py- roclastics of basaltic composition. The unit with widespread out- crops in the study area has a lateral transition to the limestone member. Basalts with basal structures indicating submarine vol- canism are a purple-black colour, with large glassy minerals, abundant fractures, and joints (Fig. 2c). Pyroclastics are lightly coloured, with uneven erosion surfaces and glass fragments (AKÇAY et al., 2007) (Fig. 2g). The unit has a broad distribution in the study area. Manganese mineralization is observed as bands and occasional stockwork at the contact with limestone and within the limestones (Fig. 2, d-f). 4.1. Ore Petrography Polished sections of the mineralized samples were investigated with­a­reflected­light­microscope.­Additionally,­XRD­analysis­ Ta bl e 1. M aj or o xi de c on te nt s ( % ) i n th e or e sa m pl es . Sa m pl es % E- 1 E- 3 E- 6 E- 7 E- 9 E- 10 E- 13 E- 14 E- 15 E- 16 E- 17 E- 18 E- 19 E- 20 E- 21 E- 22 E- 23 E- 24 E- 25 E- 26 M in . M ax . Av e. Si O 2 0. 40 13 .9 0 2. 30 8. 80 10 .4 0 61 .0 0 35 .4 0 38 .5 0 0. 50 12 .0 0 2. 50 9. 10 11 .3 0 62 .0 0 33 .2 0 37 .0 0 1. 50 8. 10 11 .6 0 3. 90 0. 40 62 .0 0 18 .1 7 A l 2O 3 0. 10 4. 00 0. 60 0. 70 5. 50 0. 10 0. 10 0. 10 0. 20 3. 30 0. 40 0. 50 5. 40 0. 10 0. 20 0. 10 0. 30 0. 40 0. 10 0. 50 0. 10 5. 50 1. 14 Ca O 50 .2 0 11 .7 0 21 .1 0 4. 80 26 .9 0 2. 50 15 .4 0 0. 40 48 .1 0 12 .5 0 20 .0 0 5. 10 27 .8 0 3. 50 16 .2 0 0. 50 10 .0 0 19 .2 0 3. 80 15 .4 0 0. 40 50 .2 0 15 .7 6 Fe 2O 3 0. 1 2. 40 0. 40 42 .1 0 2. 40 14 .2 0 21 .5 0 33 .6 0 0. 20 3. 40 0. 30 43 .1 0 2. 50 14 .8 0 21 .0 0 30 .5 0 38 .5 0 2. 20 0. 50 39 .9 0 0. 20 43 .1 0 16 .5 0 K 2 O 0. 10 1. 90 0. 10 0. 80 1. 70 0. 10 0. 10 0. 10 0. 10 1. 50 0. 20 0. 80 1. 50 1. 70 0. 10 1. 80 0. 30 0. 60 0. 10 0. 10 0. 10 1. 90 0. 69 M gO 0. 30 0. 80 0. 40 1. 40 1. 00 0. 30 0. 30 0. 40 0. 30 0. 70 0. 20 1. 20 0. 90 0. 20 0. 40 0. 30 0. 20 0. 10 0. 80 0. 60 0. 10 1. 40 0. 54 M nO 9. 20 48 .4 0 52 .2 0 26 .9 0 19 .4 0 14 .9 0 11 .3 0 18 .0 0 10 .1 0 45 .3 0 50 .9 0 27 .3 0 20 .3 0 15 .1 0 12 .8 0 19 .2 0 21 .5 0 47 .3 0 55 .2 0 28 .0 0 9. 20 55 .2 0 27 .6 7 N a 2 O 0. 10 0. 10 0. 10 0. 10 0. 40 0. 10 0. 10 0. 10 0. 10 0. 10 0. 20 0. 30 0. 10 0. 20 0. 10 0. 10 0. 20 0. 10 0. 10 0. 30 0. 10 0. 40 0. 15 P 2 O 5 0. 10 0. 20 0. 40 0. 10 0. 30 0. 10 0. 10 0. 10 0. 10 0. 30 0. 20 0. 40 0. 30 0. 10 0. 20 0. 40 0. 20 0. 10 0. 10 0. 20 0. 10 0. 40 0. 20 Ti O 2 0. 10 0. 20 0. 10 0. 10 0. 30 0. 10 0. 10 0. 10 0. 20 0. 10 0. 30 0. 10 0. 10 0. 20 0. 30 0. 20 0. 10 0. 10 0. 20 0. 30 0. 10 0. 30 0. 17 LO I 39 .0 0 16 .5 0 21 .9 0 13 .9 0 23 .5 5 6. 40 16 .0 0 0. 40 39 .0 0 19 .9 0 24 .5 0 11 .7 0 28 .7 0 1. 70 16 .4 0 9. 20 24 .8 0 20 .0 0 26 .4 0 9. 40 0. 40 39 .0 0 18 .4 7 M n/ Fe 10 1. 86 22 .3 1 14 4. 39 0. 71 8. 94 1. 16 0. 58 0. 59 55 .8 6 14 .7 4 18 7. 71 0. 70 8. 98 1. 13 0. 67 0. 70 0. 62 23 .7 9 12 2. 14 0. 78 0. 58 18 7. 71 34 .9 2 A l 2O 3/ Ti O 2 1. 00 20 .0 0 6. 00 7. 00 18 .3 3 1. 00 1. 00 1. 00 1. 00 33 .0 0 1. 33 5. 00 54 .0 0 0. 50 0. 67 0. 50 3. 00 4. 00 0. 50 1. 67 0. 50 54 .0 0 8. 03 G eo lo gi a C ro at ic a 290 Geologia Croatica 74/3 was performed to support the mineral paragenesis (Fig. 3). Ac- cordingly, the main minerals in the ore paragenesis were pyro- lusite, goethite, and ramsdellite. Lesser amounts of magnetite were­observed.­The­gangue­minerals­comprise­calcite­and­quartz.­ Pyrolusite is the most abundant manganese oxide mineral in manganese­deposits.­There­are­three­different­polymorphs­of­ MnO2. The most stable and abundant of these is pyrolusite, which is a mineral that may form in both supergene and low-tempera- ture hydrothermal environments and does not infer meaning in terms of origin (NICHOLSON, 1992). Apart from this, other manganese minerals including ramsdellite and manganite occur in the form of replacements. Pyrolusite formation is typical with weathering developing in terrestrial environments. In this type of mineralization, pyrolusite may contain simple remnant mate- rials from the environment during transport and pyrolusite pre- cipitation generally occurs in carbonate rocks including lime- stone or dolomite (RAMDOHR, 1980). In environments with a high oxidation potential, pyrolusite may be independent of pH (KRAUSKOPF, 1989). It displays a cream and yellow colour un- der­the­first­Nicol,­while­there­is­cream,­yellow,­bluish­grey­strong­ Figure 2. a, b. Limestone member: fossiliferous limestone comprising sandy-silty limestone and massive limestones, c. Black basalt with abundant fractures and joints showing basal structures indicating submarine volcanism. Mn: manganese, Bs: basalt; Pr: Pyroclastics, Kct: limestone, d, e, f. Banded and occasionally stock- work mineralization at basalt-limestone contacts and within the limestone. g. Light-coloured pyroclastics with undulating erosion surface. Figure 3. X-ray diffractogram for the mineralized samples. G eologia C roatica 291Öksüz and Kaya: Genesis of Ferromanganese Deposits from the Central Anatolian Province, Yozgat-Aşağı Eğerci Village-TURKEY ... anisotropy under the second Nicol (Fig. 4a, b). There are three different­pyrolusite­types­in­the­study­area­(Fig.­4c).­One­of­these­ is­vein­fill­with­small­grain­size­(Fig.­4d),­while­the­other­has­ larger grains in the form of foliation (Fig. 4c, e, f). Additionally, pyrolusites were observed in the form of replacements with rams- dellite (Fig. 4e-h). Ramsdellite is one of the naturally occurring manganese ox- ide polymorphs. Due its similarities with pyrolusite, it is very difficult­to­make­a­direct­comparison.­Though­pyrolusite­is­more­ commonly observed, ramsdellite may be found in abundant amounts­in­manganese­rich­environments­exposed­to­aqueous­ alteration at low temperatures (OSTWALD et al., 1984). If the two minerals form together, pyrolusite is notable for its higher sheen. Both minerals are included in the paragenesis of the other, and ramsdellite converts to pyrolusite when heated above 300 oC (RAMDOHR, 1980). This type of transformation is in the form Figure 4. Polished section photographs of mineralized samples. a. Cream and yellow goethite replacing pyrolusite and brecciated light and dark grey colour goe- thite (I Nicol), b. Bluey grey, strongly anisotropic pyrolusite and orange-brown goethite with strong internal reflection (II Nicol). c. Foliation in large-grained (Py-I) and fine-grained pyrolusite (Py-II). d. Fine-grained, vein-fill pyrolusite (I Nicol), light and dark grey goethite with occasional oolite-like texture (I Nicol). e. Cream, bright yellow ramsdellite and pyrolusite were observed replacing ramsdellite (I Nicol). f. Same photograph (II Nicol). Py: pyrolusite, Gth: goethite, R: ramsdellite. G eo lo gi a C ro at ic a 292 Geologia Croatica 74/3 Ta bl e 2. Tr ac e el em en ts c on te nt s ( pp m ) i n th e or e sa m pl es . pp m E- 1 E- 3 E- 6 E- 7 E- 9 E- 10 E- 13 E- 14 E- 15 E- 16 E- 17 E- 18 E- 19 E- 20 E- 21 E- 22 E- 23 E- 24 E- 25 E- 26 M in . M ax . Av e. A s 15 .2 12 0. 0 74 .2 41 2. 0 52 .6 19 5. 3 20 6. 0 26 9. 5 16 .3 12 5. 0 75 .5 39 8. 9 55 .4 20 0. 3 20 4. 0 28 0. 2 18 .3 11 5. 8 78 .1 15 3. 3 15 .2 41 2. 0 15 3. 3 Be 0. 2 1. 7 1. 0 1. 8 0. 8 0. 1 2. 1 0. 3 0. 2 1. 6 0. 9 1. 8 0. 7 0. 3 1. 9 0. 1 1. 7 2. 3 0. 1 1. 0 0. 1 2. 3 1. 0 Bi 1. 3 18 .9 18 .1 10 .8 3. 3 2. 8 3. 4 8. 8 1. 2 18 .4 17 .8 10 .4 3. 5 2. 5 3. 4 8. 9 1. 5 17 .5 9. 2 8. 5 1. 2 18 .9 8. 5 Cd <0 .1 1. 2 1. 1 17 .1 0. 2 5. 7 7. 1 13 .0 0. 9 1. 5 1. 2 15 .2 0. 5 5. 8 7. 5 12 .4 4. 2 1. 2 1. 4 5. 4 0. 2 17 .1 5. 4 Co 4. 5 45 .6 37 .1 38 .3 19 .7 28 .5 19 .9 22 .3 4. 2 43 .2 36 .8 35 .2 18 .9 29 .1 18 .4 24 .1 4. 6 44 .9 36 .5 26 .9 4. 2 45 .6 26 .9 Cu 16 .0 22 9. 6 22 4. 9 10 8. 6 55 .1 11 .4 4. 1 <0 .1 15 .8 22 32 .1 22 7. 2 10 6. 6 54 .9 10 .8 4. 9 0. 2 14 .9 20 5. 8 19 0. 0 20 6. 3 0. 2 22 32 .1 20 6. 3 G a 2. 4 12 .7 11 .2 10 .6 9. 8 3. 6 7. 6 4. 6 2. 3 11 .9 10 .9 10 .3 9. 7 3. 3 7. 5 4. 2 2. 1 11 .8 10 .9 7. 8 2. 1 12 .7 7. 8 G e 0. 3 1. 2 0. 9 5. 4 0. 7 2. 0 2. 6 4. 2 0. 2 1. 3 0. 8 5. 2 0. 7 1. 9 2. 4 4. 3 0. 3 1. 3 0. 7 1. 9 0. 2 5. 4 1. 9 H f <0 .1 1. 5 0. 4 0. 2 2. 6 <0 .1 0. 1 0. 1 0. 1 1. 4 0. 3 0. 2 2. 4 0. 1 0. 1 1. 2 0. 9 2. 2 0. 4 0. 8 0. 1 2. 6 0. 8 In <0 .1 <0 .1 <0 .1 <0 .1 <0 .1 <0 .1 <0 .1 <0 .1 <0 .1 <0 .1 <0 .1 <0 .1 <0 .1 <0 .1 <0 .1 <0 .1 <0 .1 <0 .1 <0 .1 <0 .1 <0 .1 <0 .1 <0 .1 M o 3. 0 38 .5 23 .1 33 .4 20 .5 18 .2 15 .6 21 .7 2. 9 37 .5 22 .9 34 .2 20 .2 17 .4 15 .4 19 .8 20 .5 31 .2 15 .2 21 .6 2. 9 38 .5 21 .6 N i 23 .7 91 .9 25 2. 1 10 4. 4 61 .6 91 .2 25 .1 16 .1 23 .4 89 .2 24 5. 2 10 3. 2 30 .8 90 .8 89 .5 25 .3 17 .5 21 .5 15 .8 74 .6 15 .8 25 2. 1 74 .6 Sb 0. 7 3. 3 3. 1 7. 9 1. 5 3. 6 1. 6 3. 2 0. 6 3. 2 3. 1 8. 1 1. 4 3. 3 1. 4 3. 1 0. 7 3. 6 5. 4 3. 1 0. 6 8. 1 3. 1 Tl 0. 4 0. 3 9. 9 0. 3 0. 2 <0 .1 <0 .1 <0 .1 0. 4 0. 5 8. 9 0. 2 0. 1 0. 3 0. 1 0. 4 0. 2 0. 1 0. 1 1. 4 0. 1 9. 9 1. 4 Ba 14 8. 4 35 50 .1 47 50 .0 38 25 .0 93 0. 2 30 33 .3 62 19 .1 54 06 .7 15 0. 2 36 70 .0 48 20 .0 38 32 .0 89 0. 0 30 27 .0 63 15 .0 53 21 .0 29 80 .0 45 20 .0 39 25 .0 36 87 .9 14 8. 4 63 15 .0 36 87 .9 Cr 7. 8 40 .9 23 .4 14 .0 53 .2 11 .5 7. 0 10 .5 7. 6 35 .2 22 .1 15 .1 52 .1 10 .9 6. 9 10 .3 8. 1 41 .2 21 .5 21 .6 6. 9 53 .2 21 .6 Cs 0. 5 0. 9 0. 2 1. 6 1. 6 0. 1 0. 2 0. 1 0. 4 0. 8 0. 2 1. 5 1. 6 0. 2 0. 1 1. 4 0. 4 0. 8 1. 2 0. 7 0. 1 1. 6 0. 7 N b 0. 3 2. 6 0. 8 0. 4 5. 0 0. 1 0. 2 0. 2 0. 2 2. 4 0. 7 0. 4 4. 8 0. 1 0. 3 2. 1 3. 2 0. 1 0. 2 1. 3 0. 1 5. 0 1. 3 Pb 10 .6 64 .8 39 .9 49 .4 39 .9 23 .5 24 .1 40 .7 10 .5 60 .2 38 .1 42 .5 37 .1 22 .9 24 .5 39 .7 9. 9 63 .9 42 .6 36 .0 9. 9 64 .8 36 .0 Rb 10 .5 58 .0 23 .0 41 .5 54 .3 12 .3 7. 2 8. 8 10 .4 54 .5 23 .5 40 .9 52 .8 11 .9 7. 5 8. 6 9. 8 55 .2 25 .4 27 .2 7. 2 58 .0 27 .2 Sr 19 6. 4 82 3. 0 83 4. 5 80 6. 3 32 1. 0 42 4. 0 57 8. 0 49 4. 5 19 4. 5 82 0. 8 85 0. 2 80 4. 1 32 5. 4 42 5. 3 58 0. 5 47 0. 8 20 5. 0 56 2. 2 49 2. 5 53 7. 3 19 4. 5 85 0. 2 53 7. 3 Ta 0. 1 0. 4 0. 2 0. 3 0. 6 0. 6 0. 4 0. 4 0. 1 0. 3 0. 2 0. 4 0. 5 0. 6 0. 4 0. 1 0. 2 0. 3 0. 4 0. 3 0. 1 0. 6 0. 3 Zr 3. 3 73 .6 25 .7 12 .2 13 4. 0 1. 2 4. 6 3. 6 3. 2 74 .1 24 .2 13 .5 12 0. 4 1. 5 5. 1 3. 7 3. 2 70 .5 24 .8 31 .7 1. 2 13 4. 0 31 .7 H f 0. 1 1. 5 0. 4 0. 2 2. 8 0. 1 0. 1 0. 1 1. 5 0. 3 0. 1 0. 2 2. 5 1. 2 0. 1 0. 2 2. 1 1. 2 0. 1 0. 8 0. 1 2. 8 0. 8 Sc 2. 1 5. 6 2. 6 2. 1 7. 3 1. 6 1. 7 1. 8 1. 9 5. 2 2. 5 2. 2 7. 4 1. 4 1. 2 1. 8 2. 3 5. 1 2. 8 3. 2 1. 2 7. 4 3. 2 Th 0. 7 2. 2 0. 9 0. 8 3. 9 0. 1 0. 3 0. 3 0. 6 2. 1 0. 9 3. 7 0. 1 0. 2 0. 6 2. 7 0. 3 0. 1 0. 4 1. 1 0. 1 3. 9 1. 1 U 0. 9 7. 9 3. 0 2. 6 3. 8 2. 4 4. 6 9. 8 0. 8 7. 5 2. 9 2. 5 3. 7 2. 2 4. 4 9. 7 0. 9 7. 4 2. 9 4. 2 0. 8 9. 8 4. 2 V 30 .9 23 8. 5 16 5. 0 28 1. 8 12 1. 3 11 6. 4 31 .7 75 .4 29 .8 23 4. 2 17 0. 8 28 5. 1 11 9. 8 11 5. 4 30 .8 74 .2 12 0. 2 25 0. 7 28 .9 13 2. 7 28 .9 28 5. 1 13 2. 7 Co /N i 0. 1 0. 5 0. 3 0. 2 0. 7 0. 1 0. 1 0. 1 0. 1 0. 5 0. 3 0. 2 0. 6 0. 1 0. 3 1. 2 1. 4 0. 0 0. 1 0. 4 0. 0 1. 4 0. 4 V/ (V +N i) 23 .1 15 8. 5 83 .5 64 .1 19 5. 6 19 .2 39 .1 32 .4 30 .4 16 0. 6 86 .4 74 .3 18 5. 6 21 .0 20 .4 3. 2 2. 3 35 95 .5 34 7. 2 81 .0 2. 3 35 95 .5 26 1. 2 Sr /B a 1. 3 0. 2 0. 2 0. 2 0. 3 0. 1 0. 1 0. 1 1. 3 0. 2 0. 2 0. 2 0. 4 0. 1 0. 1 0. 1 0. 1 0. 1 0. 1 0. 1 0. 1 1. 3 0. 3 G eologia C roatica 293Öksüz and Kaya: Genesis of Ferromanganese Deposits from the Central Anatolian Province, Yozgat-Aşağı Eğerci Village-TURKEY ... of nested or small pyrolusites observed surrounding ramsdellite in­the­study­area­(Fig.­4e­h).­Ramsdellite­identified­with­XRD­is­ differentiated­from­pyrolusite­by­its­greenish­grey­anisotropy­ colo ur especially (see Fig. 3; Fig. 4f, h; Fig. 5b). The other mineral commonly observed in mineralization in the study area is goethite. Goethite observed on both XRD and ore­microscopy­shows­the­presence­of­several­different­stages­ within the mineralization (Fig. 4a b; Fig. 5c-h). Goethite is ob- served­with­different­shades­of­grey­under­the­first­Nicol­and­has­ typical­yellow,­orange,­and­red­internal­reflection­under­the­se­ cond Nicol (Fig. 5d, f, h). In some samples, oolitic textures in goe- thite are very pronounced (Fig. 5g, h). Though these textures are actually sedimentation textures, similar shapes may form in min- eralization developing from solutions and melts in some circum- stances. Though the resemblance of these textures to bacteria was discussed­at­first,­later­studies­state­that­they­represent­a­hydro- Figure 5. Polished section photographs of mineralized samples. a. Ramsdellite in the form of veins within goethite (I Nicol), b. Ramsdellite with strong greenish anisotropy (II Nicol). c. Colloid texture, greyish colour goethite (I Nicol). d. Colloid texture goethite with clear orange internal reflection (II Nicol). e. Colloid texture, greyish colour goethite (I Nicol). f. Colloid texture goethite with clear orange internal reflection (II Nicol). g. Light and dark grey goethite with oolitic texture (I Nicol). h. goethite with oolitic texture showing red and orange internal reflection (II Nicol). Py: pyrolusite, Gth: goethite, R: ramsdellite. G eo lo gi a C ro at ic a 294 Geologia Croatica 74/3 Ta bl e 3. R ar e ea rt h el em en ts (R EE ) c on te nt s ( pp m ) i n th e or e sa m pl es . Sa m pl e pp m E- 1 E- 3 E- 6 E- 7 E- 9 E- 10 E- 13 E- 14 E- 15 E- 16 E- 17 E- 18 E- 19 E- 20 E- 21 E- 22 E- 23 E- 24 E- 25 E- 26 M in . M ax . Av e. La 2. 80 14 .0 0 10 .0 0 6. 00 15 .2 0 0. 60 2. 60 2. 00 2. 70 13 .0 0 9. 90 5. 60 15 .1 0 0. 50 2. 40 1. 90 3. 00 15 .2 0 2. 40 6. 57 0. 50 15 .2 0 6. 57 Ce 2. 70 24 .3 0 16 .1 0 11 .1 0 20 .8 0 0. 20 2. 90 2. 00 2. 60 24 .5 0 15 .8 0 10 .5 0 19 .7 0 0. 40 2. 70 2. 20 2. 40 20 .3 0 0. 20 9. 55 0. 20 24 .5 0 9. 55 Pr 0. 40 2. 30 1. 60 1. 10 2. 60 0. 10 0. 30 0. 20 0. 30 2. 40 1. 30 1. 30 2. 50 0. 10 0. 40 0. 20 2. 10 0. 30 1. 80 1. 12 0. 10 2. 60 1. 12 N d 1. 90 10 .1 0 7. 30 4. 50 11 .3 0 0. 20 1. 50 0. 80 1. 70 10 .5 0 6. 40 4. 60 10 .9 0 0. 20 1. 60 0. 70 8. 90 6. 90 1. 70 4. 83 0. 20 11 .3 0 4. 83 Sm 0. 30 1. 80 1. 30 0. 80 2. 00 0. 10 0. 30 0. 10 0. 20 1. 60 1. 20 0. 60 1. 90 0. 10 0. 20 0. 10 0. 30 0. 40 0. 40 0. 72 0. 10 2. 00 0. 72 Eu 0. 10 1. 40 1. 40 1. 10 0. 80 0. 70 1. 50 1. 20 0. 10 1. 20 1. 40 1. 20 0. 90 0. 60 1. 40 1. 60 0. 90 1. 30 0. 60 1. 02 0. 10 1. 60 1. 02 G d 0. 40 2. 00 1. 50 1. 00 2. 10 0. 10 0. 40 0. 20 0. 30 1. 80 1. 40 0. 90 2. 30 0. 10 0. 30 0. 20 0. 40 1. 50 0. 30 0. 91 0. 10 2. 30 0. 91 Tb 0. 10 0. 30 0. 30 0. 20 0. 40 0. 10 0. 10 0. 10 0. 10 0. 20 0. 30 0. 40 0. 20 0. 10 0. 20 0. 30 0. 10 0. 20 0. 10 0. 20 0. 10 0. 40 0. 20 D y 0. 4 2. 40 1. 80 1. 10 2. 40 0. 10 0. 30 0. 10 0. 30 2. 30 1. 70 1. 30 2. 20 0. 10 0. 30 0. 10 0. 30 2. 10 1. 80 1. 15 0. 10 2. 40 1. 15 H o 0. 10 0. 50 0. 40 0. 30 0. 50 0. 10 0. 10 0. 10 0. 10 0. 40 0. 30 0. 40 0. 50 0. 10 0. 10 0. 20 0. 30 0. 50 0. 20 0. 27 0. 10 0. 50 0. 27 Er 0. 3 1. 60 1. 20 0. 80 1. 50 0. 10 0. 20 0. 10 0. 30 1. 40 1. 60 0. 70 1. 20 0. 10 0. 20 0. 70 0. 10 0. 20 0. 70 0. 71 0. 10 1. 60 0. 71 Tm 0. 10 0. 20 0. 20 0. 10 0. 20 0. 10 0. 10 0. 10 0. 10 0. 20 0. 30 0. 10 0. 20 0. 10 0. 10 0. 20 0. 30 0. 10 0. 10 0. 15 0. 10 0. 30 0. 15 Yb 0. 20 1. 60 1. 30 0. 70 1. 40 0. 10 0. 20 0. 10 1. 10 0. 20 1. 50 1. 20 0. 60 1. 30 0. 10 0. 20 0. 10 0. 30 1. 40 0. 70 0. 10 1. 60 0. 72 Lu 0. 10 0. 20 0. 20 0. 10 0. 20 0. 10 0. 10 0. 10 0. 10 0. 20 0. 20 0. 10 0. 20 0. 10 0. 10 0. 10 0. 20 0. 10 0. 20 0. 14 0. 10 0. 20 0. 14 Y 4. 20 19 .4 0 15 .6 0 12 .0 0 19 .6 0 0. 70 5. 10 2. 50 4. 30 19 .2 0 14 .2 0 12 .5 0 19 .8 0 0. 50 5. 40 2. 40 9. 80 4. 80 5. 50 9. 25 0. 50 19 .8 0 9. 34 ∑R EE 9. 90 62 .7 0 44 .6 0 28 .9 0 61 .4 0 2. 70 10 .6 0 7. 20 10 .0 0 59 .9 0 43 .3 0 28 .9 0 58 .4 0 3. 90 10 .1 0 8. 70 19 .4 0 49 .4 0 11 .9 0 28 .0 4 2. 70 62 .7 0 28 .0 0 ∑L RE E/ ∑H RE E 4. 82 6. 13 5. 46 5. 72 6. 06 2. 38 6. 07 7. 00 3. 17 7. 94 4. 93 4. 67 6. 89 0. 95 6. 21 3. 35 9. 78 8. 88 1. 48 5. 63 0. 95 9. 78 5. 38 Ce * 0. 47 0. 83 0. 77 0. 87 0. 65 0. 16 0. 56 0. 51 0. 49 0. 88 0. 79 0. 84 0. 62 0. 37 0. 54 0. 59 0. 24 0. 76 0. 02 0. 69 0. 02 0. 88 0. 58 Pr * 1. 01 0. 84 0. 84 0. 89 0. 97 2. 85 0. 82 0. 90 0. 81 0. 85 0. 74 1. 07 0. 97 2. 02 1. 10 0. 92 2. 59 0. 14 17 .6 1 0. 94 0. 14 17 .6 1 1. 94 Ce an om -0 .3 2 -0 .0 7 -0 .1 1 -0 .0 5 -0 .1 8 -0 .7 5 -0 .2 5 -0 .2 8 -0 .3 2 -0 .0 4 -0 .1 0 -0 .0 5 -0 .2 0 -0 .3 8 -0 .2 5 -0 .2 1 -0 .5 8 -0 .1 6 -1 .3 9 -0 .1 5 -1 .3 9 -0 .0 4 -0 .2 9 Eu * 0. 88 2. 18 2. 99 3. 72 1. 14 20 .2 4 13 .2 5 48 .1 0 1. 27 2. 10 3. 23 5. 09 1. 30 17 .3 5 17 .8 0 36 .3 2 7. 95 5. 36 4. 66 3. 83 0. 88 48 .1 0 9. 94 La N /Y b N 9. 37 5. 86 5. 15 5. 74 7. 27 4. 02 8. 70 13 .3 9 1. 64 43 .5 2 4. 42 3. 12 16 .8 5 0. 26 16 .0 7 6. 36 20 .0 9 33 .9 2 1. 15 6. 29 0. 26 43 .5 2 10 .6 6 Y/ H o 42 .0 0 38 .8 0 39 .0 0 40 .0 0 39 .2 0 7. 00 51 .0 0 25 .0 0 43 .0 0 48 .0 0 47 .3 3 31 .2 5 39 .6 0 5. 00 54 .0 0 12 .0 0 32 .6 7 9. 60 27 .5 0 33 .7 9 5. 00 54 .0 0 33 .2 9 Tb /Y b 2. 20 0. 83 1. 02 1. 26 1. 26 4. 41 2. 20 4. 41 0. 40 4. 41 0. 88 1. 47 1. 47 0. 34 8. 82 6. 61 4. 41 2. 94 0. 31 1. 26 0. 31 8. 82 2. 55 Ce * = Ce N /[2 /3 La N +1 /3 Pr N ] ΣL RE E = La +C e+ Pr +N d+ Sm +E u Eu * = Eu no rm /[2 /3 Sm no rm +1 /3 G d n or m ] ΣH RE E = G d+ Tb +D y+ H o+ Er +T m +Y b+ Lu Ce an om = lo g [3 x Ce N /(2 x L a N + N d N )] Pr * = Pr N /(C e N × N d N )1/ 2 G eologia C roatica 295Öksüz and Kaya: Genesis of Ferromanganese Deposits from the Central Anatolian Province, Yozgat-Aşağı Eğerci Village-TURKEY ... thermal source of mineralization (RAMDOHR, 1980; GÖYMEN & KOÇ, 2000). Additionally, goethite in the study area contains widely observed colloidal textures (Fig. 5c-f), which are known to be sedimentation markers (SCHWARTZ, 1951). Goethite, which also shows brecciated structures, is another indicator of sedimentary formation (Fig. 4a, b). 5. RESULTS 5.1. Trace and Major Elements Ore samples from the study area had Mn contents of 7.1-42.8 wt% (average 21.4 wt%) and Fe contents of 0.1-30.2 (average 11.0 wt%). The Mn/Fe ratio was 0.6-187.7 (average 34.9) (Table 1). Eğerci­village­ferromanganese­mineralization­had­Al2O3/TiO2 ratios determined as 0.5-54.0 (ave. 8.0) (Table 1). The samples from the deposit in this study had Co/Ni values above 2 for 4 samples and below 1 for 16 samples (Table 2). Ore sample V/(V+Ni) ratios were below 0.60 for 8 samples, but above 0.60 for 12 samples (Table 2). The Mo and Co contents in ore samples were 2.90-38.50 ppm (average 21.64 ppm) and 4.20-45.60 ppm (ave. 26.94) in the study area, respectively (Table 2). The Ba and As concentrations were 148.40-6315 ppm (avera ge 3687.93 ppm) and 15.20-412.00 ppm (ave. 153.29 ppm) in ore samples in the study area, respectively (Table 2). Samples from the study area had Sr/Ba ratios from 0.07-1.32 (ave. 0.28). The geochemical data for ore samples from the study area were plotted on a Fe-(Ni+Co+Cu)x10-Mn ternary diagram (Fig. 6a; BONATTI et al., 1972). Accordingly, all samples were dis- tributed­in­the­hydrothermal­field.­ The source diagram determined with the Na/Mg ratio (NI- CHOLSON 1992) showed that all samples were distributed in the freshwater­field­(Fig.­6b).­Fig.­6c­shows­the­Fe/Ti­ratio­plotted­ against Al/(Al+Fe+Mn) (Fig. 6c; BOSTROM et al., 1976). On the 10×MgO-Fe2O3-MnO2 (CONLY et al., 2011) ternary diagram, ore samples were distributed in the marine hydrother- mal, continental hydrothermal, marine hydrogenetic and fresh- water­hydrogenetic­fields­(Fig.­6d).­ 5.2. REE Geochemistry The REE content of samples was used to assess the geochemical parameters of ore mineralization in the study area. REE, com- monly used for assessing sources, were analyzed in 20 ore sam- ples taken from the study area. Analysis of the results and some calculations are given in Table 3. ΣREE data had values from 2.70-62.70 ppm with an average (ave.) 28.00 ppm. Additionally, the LREE/HREE ratio in ore samples from the study area was 0.95-9.78 (ave. 5.38) and this value shows that LREE values were enriched compared to HREE values. This enrichment is 0.31-8.82 (ave. 2.55) ratios (Fig. 7). Additionally, Eu and Ce anomalies were assessed. REE data were normalized to chondrite and plotted on spider diagrams (Fig. 7). As seen on the spider diagram for the Eu anomaly, there is a high positive anomaly (Fig. 7). When anomaly values are calculated with the formula Eu*=EuN/ [2/3SmN+1/3GdN], apart from one sample, all displayed a high positive anomaly (0.88-48.10, ave 9.94) (Tablo 3). In some situa- tions, La enrichment causes false-negative Ce anomalies (BAU & DULSKI, 1999; KATO et al., 2006; PLANAVSKY et al., 2010). For­this­reason,­the­Ce*­anomaly­is­determined­with­two­differ- ent calculations. Ce*=CeN/[2/3LaN+1/3PrN] and Pr*=PrN/ (CeN×NdN)1/2 calculations were performed. With Ce* calcula- tions, negative anomalies were supported for all samples (0.02- 0.88, ave 0.58) (Tablo 3). As a result of Pr* calculation, though 6 samples were observed to have a positive anomaly, 14 samples were observed to have a negative anomaly, and the negative anomaly observed in most samples supports the Ce* calculations (Table 3). Ceanom data were calculated with the formula Ceanom = log(3CeN/(2LaN+NdN) (WRIGHT et al., 1987). When data from Table 4. Microthermometric fluid inclusion data from Eğerci village ferroman- ganese ore samples. Sample No Mineral Vapor Ratio Fl Types Homog. Mode Te, oC Tm-ice, oC Th, oC Salinity (wt% NaCl equiv.) E-1 Quartz 5–20 Type III Liquid –33.8 –2.3 176 3.9 5–20 Type III Liquid –37 –2 216 3.4 5–20 Type III Liquid –37.7 –1.7 186 2.9 5–20 Type III Liquid –37.6 –1.2 191 2.1 5–20 Type III Liquid –42.6 –1.3 205 2.2 30–60 Type I Vapor –1.4 354 2.4 5–20 Type III Liquid –1.4 163 2.4 30–60 Type III Vapor –45.4 –6.4 422 9.8 5–20 Tip III Liquid –34.1 –1.7 227 2.9 5–20 Type III Liquid –44.7 –2.4 236 4.0 30–60 Type I Vapor –47.8 –5.6 382 8.7 30–60 Type I Vapor –33.8 –1.5 347 2.6 20–30 Tip II Liquid –36.9 –1.4 298 2.4 E-2 Quartz 5./20 Type III Liquid –34.8 –1.6 221 2.7 5–20 Type III Liquid –40 –1.1 231 1.9 20–30 Tip II Liquid –34.5 –1.1 304 1.9 5–20 Type III Liquid –46 –1.6 217 2.7 20–30 Type II Liquid –1.6 269 2.7 20–30 Type II Liquid –38.1 –1.7 301 2.9 5–20 Type III Liquid –1.6 191 2.7 5–20 Type III Liquid –37.3 –1.8 209 3.1 30–60 Type I Vapor –1.1 346 1.9 30–60 Type I Vapor –1.5 377 2.6 5–20 Type III Liquid 187 E-3 Quartz 30/60 Type I Vapor –40.8 –6.1 397 9.4 30–60 Type I Vapor –5.4 361 8.5 30–60 Type I Vapor –44.2 –6.2 374 9.6 30–60 Type I Vapor –46 –7.3 431 11.0 30–60 Type I Vapor –49.9 –5.9 338 9.2 30–60 Type I Vapor –7.9 401 11.7 30–60 Type I Vapor –6 411 9.3 30–60 Type I Vapor –47.3 –8.1 417 12.0 30–60 Type I Vapor –9.4 438 13.5 E-4 Quartz 40–60 Type I Vapor –43.3 –1.3 367 2.2 40–60 Type I Vapor –46.8 –10.5 406 14.7 20–30 Type II Liquid –1.4 319 2.4 5–20 Tip III Liquid –2 143 3.4 40–60 Type I Vapor –1.4 376 2.4 40–60 Type I Vapor –1.5 394 2.6 40–60 Type I Vapor –3.8 362 6.2 20–30 Type II Liquid –2.9 277 4.8 20–30 Type II Liquid –2.4 296 4.0 20–30 Type II Liquid –3.1 284 5.1 40–60 Type I Vapor –2.4 388 4.0 G eo lo gi a C ro at ic a 296 Geologia Croatica 74/3 the­study­area­are­noted,­fifteen­samples­had­values­smaller­than­ ­0.1,­while­five­samples­had­values­larger­than­­0.1­(Table­3). In­the­Eğerci­village­ferromanganese­deposits,­the­Y/Ho­ra- tio was determined to be 33.29 (Table 3). 5.3. Fluid Inclusion Petrography and Microthermometry Fluid inclusion studies were performed on four samples taken from­quartz­veins­with­nearly­1­cm­thickness­located­within­car- bonate­rocks­in­the­Eğerci­village­ferromanganese­mineraliza- tion.­Along­the­veins,­quartz­crystals­grow­from­the­surfaces­of­ the wall rock towards the centre of the veins, and they have zoned growth structures (Fig. 8a). In this structure, twinned growth zones are found symmetrically on both sides of the veins, and in the­final­stage,­quartz­crystals­fill­the­cavity­in­the­centre­of­these­ growth zones. Accordingly, zone 1 and zone 2 correspond to the stage­I­and­stage­II­quartz­formations,­respectively,­while­the­fi- nal­stage­quartz­filling­in­the­centre­is­equivalent­to­3rd stage Figure 6. Discrimination diagram of the Eğerci ferromanganese mineralization. (a) Fe-(Ni+Co+Cu)x10-Mn ternary diagram (BONATTI et al., 1972); (b) Na/Mg bivariate diagram (NICHOLSON, 1992); (c) Fe/Ti vs. Al/(Al+Fe+Mn) bivariate diagram (BOSTROM et al., 1976); (d) 10×Mg-Fe2O3–MnO2–ternary diagram (CONLY et al., 2011). Figure 7. Chondrite normalized REE diagram for ore samples (Normalization values are from EVENSEN, 1978). G eologia C roatica 297Öksüz and Kaya: Genesis of Ferromanganese Deposits from the Central Anatolian Province, Yozgat-Aşağı Eğerci Village-TURKEY ... equation­proposed­by­BODNAR­(1993)­with­results­reported­in­ Table­4.­The­blank­rows­in­Table­4­are­equivalent­to­parameters­ that could not be measured. According­to­this,­three­main­fluid­inclusion­types­were­iden- tified­along­the­three­different­growth­zones­of­the­samples.­Type­ I­fluid­inclusions­are­generally­observed­to­have­irregular­geomet- ric shapes and rarely tube shapes (Fig. 8c). In some cases, negative crystal-shaped inclusions were also observed (Fig. 8d). The Type I­fluid­inclusions­in­zone­1­had­sizes­from­20­to­30­µm.­These­fluid­ quartz­formation­(Fig.­8b).­Eutectic­temperatures­(Te),­final­ice­ melting temperatures (Tm-ice), and homogenization tempera- tures­(Th)­of­the­fluid­inclusions­from­each­zone­were­measured­ by the microthermometric study, and the results are presentted in­Table­4.­Eutectic­temperatures­and­final­ice­melting­tempera- tures­of­some­fluid­inclusions­could­not­be­measured­due­to­the­ inclusion­size­being­very­small­and­not­being­sufficiently­trans- parent.­Additionally,­the­salinity­of­these­inclusions,­equivalent­ to wt.% NaCl were calculated using the Tm-ice values with the Figure 8. a. Growth zonation of the quartz vein in the carbonate host rock, b) Photomicrograph of the quartz crystals with zoned structure, c, d) Type I fluid inclu- sions in the growth zone I, e) Negative crystal-shaped Type II fluid inclusion in the growth zone II, f ) Irregular shaped Type III fluid inclusion in the final stage quartz vein, g) Negative crystal-shaped Type III fluid inclusion in the last stage quartz vein. G eo lo gi a C ro at ic a 298 Geologia Croatica 74/3 Ta bl e 5. M aj or a nd tr ac e el em en t c on te nt s o f v ar io us ty pe s o f m an ga ne se a nd fe rr om an ga ne se d ep os its . N um be r o f sa m pl es 7 28 22 15 13 11 14 7 13 23 10 20 20 Co un tr y Ch in a Pa ki st an Ira n Ja pa n Tu rk ey Re gi on G ui ch i W az iri st an H az ar a Be la Zh ob So rk hv an d W ak as a U lu ke nt Bi nk ılı c Ca yi rli Ka si m ag a Ey m ir Th is st ud y O rig in Se di m en ta ry Vo lc an o- se di m en ta ry H yd ro th er m al - H yd ro ge no us Su bm ar in e hy dr ot he rm al H yd ro th er m al H yd ro th er m al H yd ro th er m al Se di m en ta ry Se di m en ta ry / di ag en et ic Vo lc an o- se di m en ta ry Vo lc an o- se di m en ta ry H yd ro th er m al - H yd ro ge no us Si O 2 ( % ) (-) 43 .6 9 9. 41 46 .2 1 (-) 40 .8 2 58 .1 6 13 .6 8 10 .6 5 63 .0 2 13 .4 3 16 .0 4 18 .1 7 Ti O 2 ( % ) (-) 0. 32 0. 84 0. 53 0. 34 0. 03 0. 04 0. 10 0. 02 0. 03 0. 10 0. 02 0. 17 A l 2O 3 ( % ) (-) 0. 73 12 .5 3 1. 86 0. 80 0. 48 0. 55 2. 49 2. 85 0. 65 2. 95 0. 73 1. 14 Fe 2O 3 ( % ) (-) 2. 96 20 .3 3 9. 85 5. 75 2. 29 0. 92 3. 72 2. 46 0. 68 14 .3 3 0. 26 16 .5 0 M nO (% ) (-) 45 .8 8 33 .7 8 32 .9 9 42 .4 6 39 .4 7 32 .5 0 63 .7 8 33 .3 9 29 .2 2 40 .4 3 69 .9 1 27 .6 7 M gO (% ) (-) 0. 60 0. 59 0. 72 0. 18 0. 07 0. 19 1. 99 1. 27 0. 20 12 .7 2 0. 59 0. 54 Ca O (% ) (-) 1. 28 6. 43 1. 44 0. 75 0. 52 4. 15 4. 05 18 .9 6 0. 24 6. 82 2. 40 15 .7 6 N a 2 O (% ) (-) 0. 29 0. 07 0. 40 0. 30 0. 03 0. 04 0. 24 0. 39 0. 05 0. 06 0. 01 0. 15 K 2 O (% ) (-) 0. 22 0. 88 0. 58 1. 27 0. 06 0. 10 0. 05 0. 56 0. 11 0. 19 0. 05 0. 69 P 2 O 5 ( % ) (-) 0. 25 3. 73 0. 23 0. 13 0. 06 0. 10 0. 18 0. 31 0. 04 0. 08 0. 07 0. 20 Ba (p pm ) 21 2. 56 41 5. 00 63 04 .0 0 (-) (-) 10 38 .3 4 13 .7 9 42 7. 00 68 92 .0 0 12 29 .4 0 27 19 .4 0 23 64 .7 0 36 87 .9 3 V (p pm ) 16 7. 86 14 4. 00 57 3. 00 (-) (-) 30 .6 8 25 8. 00 (-) 10 6. 00 14 3. 70 10 6. 10 13 2. 00 13 2. 68 Cr (p pm ) 10 7. 21 46 .0 0 24 7. 00 37 .2 7 (-) (-) 10 .0 0 (-) 26 .0 0 13 .7 0 10 .0 0 (-) 21 .6 0 Co (p pm ) 4. 77 11 .0 0 40 4. 00 21 .2 0 12 5. 38 33 .3 5 2. 00 13 .0 0 59 .0 0 25 .2 1 49 .5 0 10 3. 50 26 .9 4 N i ( pp m ) 89 .3 9 36 .0 0 30 5. 00 17 .9 3 28 8. 46 98 .6 1 28 .0 0 10 .0 0 16 7. 00 69 .4 0 23 .0 0 67 .3 5 74 .6 5 Cu (p pm ) 31 .0 3 72 .0 0 37 5. 00 10 1. 00 20 .4 5 16 1. 18 50 .0 0 56 .0 0 26 .0 0 15 4. 90 12 6. 80 80 .5 0 20 6. 27 Zn (p pm ) 13 7. 36 64 .0 0 58 0. 00 71 .0 7 23 0. 94 64 .1 2 26 .0 0 70 .0 0 49 .0 0 66 .7 0 63 .5 0 62 .4 5 (-) Pb (p pm ) 16 .4 9 49 .0 0 23 57 .0 0 53 .3 3 46 4. 68 6. 56 11 2. 00 65 .0 0 (-) 6. 50 53 .5 0 9. 33 36 .0 4 Th (p pm ) (-) 2. 00 31 .0 0 (-) (-) 0. 28 2. 00 (-) (-) 0. 40 43 3. 20 0. 57 1. 10 Rb (p pm ) 37 .8 9 2. 00 24 .0 0 (-) (-) 3. 60 2. 00 (-) (-) 2. 90 5. 00 0. 77 27 .1 6 Sr (p pm ) 74 1. 34 (-) (-) (-) (-) 66 7. 65 85 .0 0 18 5. 00 21 00 .0 0 24 3. 40 25 5. 00 11 6. 47 53 7. 32 Y (p pm ) 21 .7 5 (-) (-) (-) (-) 5. 00 (-) 15 .0 0 33 .0 0 22 .2 0 8. 45 9. 34 N b (p pm ) 6. 70 (-) (-) (-) (-) 0. 27 3. 00 (-) (-) 0. 70 11 .1 0 0. 15 1. 27 Zr (p pm ) (-) (-) (-) (-) (-) 5. 87 12 .0 0 (-) 32 .0 0 4. 00 26 .9 0 8. 46 31 .7 1 M n/ Fe (-) 19 9. 00 2. 16 0. 27 10 5. 46 11 5. 47 39 .0 0 18 .9 8 15 .0 3 97 .1 7 12 .0 2 88 0. 33 34 .9 2 A l 2O 3/ Ti O 2 (-) 2. 28 14 .9 2 3. 49 2. 35 15 .5 3 13 .7 5 24 .9 0 14 2. 50 21 .6 7 29 .5 0 32 .5 3 8. 03 Co /N i 0. 05 0. 31 1. 32 1. 61 0. 45 0. 81 0. 07 1. 30 0. 35 0. 36 2. 15 1. 54 0. 61 Co /Z n 0. 03 0. 17 0. 70 0. 37 0. 57 0. 81 0. 08 0. 19 1. 20 0. 38 0. 78 2. 24 (-) (-) : T he re is n o an al ys is G eologia C roatica 299Öksüz and Kaya: Genesis of Ferromanganese Deposits from the Central Anatolian Province, Yozgat-Aşağı Eğerci Village-TURKEY ... inclusions­have­two­phases­and­contain­fluid­and­vapour,­and­va- pour rates vary between 40 and 60% (Fig. 8c, d). These inclusions are­isolated­from­the­other­fluid­inclusions,­and­they­are­homo­ genized into the gas phase during the heating process. The eutectic temperatures of these inclusions were measured between -33.8 and -49.9 °C. When comparing these Te tempera- tures­with­the­specific­eutectic­temperatures­of­the­different­salt­ compositions, Type I inclusions were very close to those for in- clusions with composition in the H2O-MgCl2-FeCl2-CaCl2 sys- tem (ROEDDER, 1984; SHEPHERD et al., 1985) (Fig. 10). The final­ice­melting­temperatures­of­Type­I­inclusions­were­measured­ between -1.1 to -10.5 °C. According to these values, the salinity of these inclusions was calculated to vary from 1.9 to 14.7 wt. % NaCl­equiv.­according­to­BODNAR­(1993).­The­homogenization­ temperatures­for­Type­I­fluid­inclusions­were­measured­as­338­to­ 438 °C. Type­II­fluid­inclusions­were­observed­in­growth­zone­2­in­ the­samples­(Fig.­8a,­b).­These­are­two­phase­liquid­rich­inclu- sions,­and­vapour/liquid­ratios­vary­between­20­30­%.­Type­II­ fluid­inclusions­are­generally­irregular,­but­ellipsoidal,­tubular,­and­ negative­crystal­shapes­were­also­defined­(Fig.­8e).­The­inclusion­ sizes­are­highly­variable,­ranging­from­10­to­50­µm.­During­mi- crothermometric­measurements,­Type­II­fluid­inclusions­homoge­ nized­in­the­liquid­phase.­The­Te­temperatures­were­measured­ between -34.5 and -38.1 °C, which correspond to the H2O-FeCl2- MgCl2­fluid­salt­systems­according­to­SHEPHERD­et­al.­(1985).­ The Tm-ice temperatures of Type II inclusions were measured in the range of -1.1 to -3.1 °C. The salinities calculated according to these­values­range­from­1.9­to­5.2­wt.­%­NaCl­equiv.­Type­II­fluid­ inclusion had Th temperatures varying from 269 to 319 °C. Type­III­fluid­ inclusions­were­found­ in­ the­centre­of­ the­ quartz­zones­equivalent­to­the­final­growth­stage­(Fig.­8a,­b).­In­ addition to irregular geometric shapes (Fig. 8f), tubes, and nega- tive crystal shapes (Fig. 8g) are present. These negative crystal shapes support that these inclusions are primary in origin. Their sizes­vary­from­10­to­30­µm.­The­vapour/liquid­ratio­ranges­from­ 5 to 20% (Fig. 8f, g) and homogenization of Type III inclusions occurred­in­the­liquid­phase.­Eutectic­temperatures­of­the­Type­ III inclusions were very close to the Type II inclusions (between -33.8 and -46 °C). Therefore salt compositions of the H2O-FeCl2- MgCl2 system, similar to the Type II inclusions, were also de- fined­for­the­Type­III­inclusions.­The­Tm­ice­temperatures­varied­ from -1.1 to -2.4 °C, corresponding to the salinity range from 1.9 to­4.0­wt.%­NaCl­equiv.­for­the­Type­III­inclusions.­Homogeniza- tion temperatures of these inclusions were measured between 143 to 236 °C (Table 4). 6. DISCUSSION Mineralization­in­the­study­area­was­investigated­with­field­and­ geochemical studies and the source was interpreted. Major and trace element concentrations and the behaviour of these elements (associations)­are­frequently­used­in­manganese­and­ferromanga- nese deposits (ÖKSÜZ, 2011b; POLGARI et al., 2012; ZARAS- VANDI et al., 2013). Fe/Mn ratios of the manganese and ferro- manganese deposits have been calculated by various studies in the Alpine-Himalaya belt in Turkey and the world (CHOI & HARIYA­1992;­ÖZTÜRK­1993;­GÜLTEKİN­1998;­KOÇ­et­al.,­ 2000; XIE et al., 2006; SHAH &­MOON,­2007;­KARAKUŞ­et­ al., 2010; ZARASVANDI et al., 2016; NAREGO et al., 2019; KHAN et al., 2020). Our results display some similarities with the manganese deposits of Guichi (Chine, XIE et. al., 2006), Wa- ziristan (Pakistan, SHAH & MOON, 2007), Hazara (Pakistan, SHAH & MOON, 2007), Bela (Pakistan. NAREJO et. al., 2019), Zhob (Pakistan, KHAN et. al., 2020), Sorkhvand (Iran, ZARAS- VANDI et. al., 2016), Wakasa (Japan, CHOI & HARIYA, 1992), Ulukent­ (Turkey,­ÖZTÜRK,­ 1993),­Binkılıç­ (Turkey,­GÜL- Figure 10. Te temperatures and equivalent salinity for all fluid inclusions in samples. Figure 9. Th histogram for all fluid inclusions in samples. G eo lo gi a C ro at ic a 300 Geologia Croatica 74/3 TEKIN,­ 1998),­ Çayırlı­ (Turkey,­ KARAKUŞ­ et.­ al.,­ 2010),­ Kasımağa­(Turkey,­KOÇ­et­al.,­2000)­and­Eymir­(Turkey,­OK- SUZ 2011a) in terms of the mineralizations. Accordingly, the ave- rage Mn/Fe ratios in the manganese and ferromanganese depos- its­of­Waziristan,­Bela,­Zhob,­Sorkhvand,­Çayırlı,­Kasımağa,­and­ Eymir in the ophiolite belt manganese mineralizations are 199.00, 0.27, 105.46, 115.47, 97.17, 12.02, 880.33 respectively (Table 5). In addition, the obtained results are very closely related to the manganese mineralizations of these deposits in Turkey and the world.­According­to­this­data,­the­Eğerci­village­ferromanganese­ deposit is compatible with hydrothermal exhalative manganese deposits discovered near submarine spreading centres (NICH- OLSON, 1992). In addition, the average Mn/Fe ratios in People Services­are­now­able­to­provide­us­with­a­monthly­staff­list­which­ includes­our­AL­colleagues­the­Guichi,­Ulukent,­and­Binkılıç­re- gions indicates that the manganese formations were formed from a sedimentary origin. The Mn/Fe ratios were calculated as 18.98 and­15.03­in­Ulukent­and­Binkılıç­regions,­respectively­(Table­5).­ The­average­Mn/Fe­ratios­are­not­informative­since­Mn­Fe­rela- tionships­are­defined­as­Mn/Fe<1­for­the­lacustrine­environment,­ Mn/Fe=1­for­the­hydrogenous­origin,­and­0.11 indicates a deep marine environment (DELIAN, 1994; NAYAN et al., 1994). Co/Ni ratios­in­Guichi,­Wazaristan,­Zhob,­Sorkhvand,­Wakasa,­Binkılıç,­ and­Çayırlı­regions­are­0.05,­0.31,­0.45,­0.81,­0.07,­0.35­and­0.36,­ respectively, and are lower than 1 (Table 5). In addition, it was observed­greater­than­1­in­Hazara,­Bela,­Ulukent,­Kasımağa,­and­ Eymir regions (1.32, 1.61, 1.30, 2.00, 1.54, respectively). Since this value is both below and above 1 in the ferromanganese deposits of­Eğerci­village,­it­is­thought­that­both­deep­sea­and­sedimentary­ environments­may­be­effective­in­the­formation. According to HEIN et al. (2008), high Ba and minor Co, Ni and Cu contents in manganese oxides show leaching from or- ganic-rich sediments or precipitation of barite at depth in hydro- thermal­systems.­Due­to­the­effect­of­sedimentation­and­volcanic­ activity, the Ba concentration in hydrothermal solutions is higher than seawater (MONNIN et al., 2001). Similarly, Ba contents showed high values in Waziristan, Hazara, Sorkhvand, Ulukent, Binkılıç,­Çayırlı,­Kasımağa,­and­the­Eymir­regions­where­the­ sedimentary contribution is intense (415.00, 6304.00, 1038.34, 427.00, 6892.00, 1229.40.00, 2719.40, 2364.70, 3687.93, respec- tively). According to the very high Ba content, the study area is characterized by mineralization with hydrothermal formation. High As content is a marker of sediment input to hydrothermal manganese (NICHOLSON, 1992). As enrichment in the study area was 15.20–412.00 ppm (ave. 153.29 ppm) (Table 2). This en- richment­may­be­a­marker­of­hydrothermal­fluids­(ŞAŞMAZ­et­ al., 2014). When the Sr/Ba ratio is examined, if this ratio is larger than 1, the environment is marine; if it is lower than 1, it indicates the presence of continental freshwater in the formation (XIE et al., 2006; XU et al., 2011). This ratio is variable in sedimentary Mn deposits (DOE et al., 2013). In Mn deposits with hydrothermal effects,­it­is­<0.01­(DOE­et­al.,­2013).­Samples­from­the­study­area­ had Sr/Ba ratio values of 0.07-1.32 (ave. 0.28). Apart from two Figure 11. A. Th-salinity relationships for all fluid inclusions in samples. B. Comparison of variation in Th-salinity with solution behaviour in a variety of environments. G eologia C roatica 301Öksüz and Kaya: Genesis of Ferromanganese Deposits from the Central Anatolian Province, Yozgat-Aşağı Eğerci Village-TURKEY ... samples, all ore samples had a Sr/Ba ratio lower than 1 represent- ing formation in a continental sedimentary environment for min- eralization in the study area. Vanadium is a very stable element during alteration (JI- ANCHENG et al., 2006). The V/(V+Ni) value increases linked to the increase in continental contribution. Additionally, oxic con- ditions are dominant at the time of aerobic microbial metabolic processes (JIANCHENG et al., 2006). If the V/(V+Ni) ratio is lower than 0.60, it indicates anoxic conditions at the time of mineralization (MARYNOWSKI et al., 2012). The ore sample V/(V+Ni) ratios were below 0.60 for 8 samples, but above 0.60 for 12 samples (Table 2). For this reason, oxic and anoxic condi- tions were dominant during mineralization occurring in the region. Additionally, sedimentary formation in a deep marine environment­was­effective­on­mineralization.­ Elements like As, Cu, Mo, Pb, Sb, Sr, and V are enriched in hydrothermal­fluids­(NICHOLSON,­1992).­When­these­elements­ are examined, enrichment was observed in all ore samples from the study area (Table 2). Low­Mo­content­in­ferromanganese­ore­may­reflect­the­low­ temperature­of­hydrothermal­fluids­(HEIN­et.­al.,­2008;­ŞAŞMAZ­ et al., 2014). This value was 2.90–38.50 ppm (average 21.64 ppm) in the study area so mineralization in a low-temperature hydro- thermal formation may be present (Table 2). The Co content in hydrothermal deposits is lower compared to hydrogenetic depos- its. Hence, a high Co concentration is a marker of the deep ma- rine environment (DEL RIO SALAS et al., 2008). This data re- flects­mineralization­with­a­hydrothermal­source­in­the­study­ area. Different­major­and­trace­element­differentiation­diagrams­ are­used­by­many­researchers­for­differentiation­of­manganese­ deposits­with­different­sources­(ADACHI­et­al.,­1986;­BONATTI­ et al., 1972; CHOI & HARIYA 1992; CRERAR et al., 1982; NI- CHOLSON, 1992; PETERS, 1988; SHAH & MOON, 2007; TOTH,­1980).­These­diagrams­are­used­to­differentiate­between­ hydrothermal (continental or marine) and hydrogenetic sources. The term hydrothermal is used for manganese oxides deposited by sedimentary-exhalative manganese mineralization in marine environments or direct deposition from hot springs in pools and geothermal water in terrestrial environments (NICHOLSON, 1992). The term hydrogenetic is used for deposits formed by ad- sorption or slow precipitation of material dissolved in seawater (BONATTI et al., 1972; CRERAR et al., 1982; NICHOLSON, 1992). The geochemical data for ore samples from the study area were plotted on a Fe-(Ni+Co+Cu)x10-Mn ternary diagram (Fig. 7a; BONATTI et al., 1972). Accordingly, all samples were dis- tributed­in­the­hydrothermal­field.­ The source diagram determined with the Na/Mg ratio (NI- CHOLSON, 1992) showed that all samples were distributed in the­freshwater­field­(Fig.­7b).­The­diagram­of­ the­Fe/Ti­ratio­ against Al/(Al+Fe+Mn) was drawn (BOSTROM et al., 1976). Accordingly, the presence of a volcanic input into the mineraliza- tion processes was supported (Fig. 7c). The ΣREE data obtained from ferromanganese samples had values from 2.70-62.70, an average of 28.00. Additionally, the LREE/HREE ratio in mineralized samples from the study area was 0.95-9.78 (ave 5.38) and this value shows enrichment in LREE values compared to HREE values. In hydrothermal solu- tions containing ore, HREEs are less stable than LREEs, so they primarily enrich LREE during manganese mineralization (RUH- LIN & OWEN, 1986; ZARASVANDI et al., 2013). These ΣREE values show that the mineralization is compatible with hydrother- mal­deposits­(e.g.,­Northeast­Pacific­Ocean­Baby­Bare­Deposit;­ REE = 20.6–249.6 JIANCHENG et al., 2006), while they are very low compared to values from hydrogenetic deposits (e.g., Hazara deposit;­ΣREE=­791­ppm;­SHAH­& MOON, 2007). It is known that­the­ΣREE­contents­of­ferromanganese­hydrothermal­depos- its are lower compared to the hydrogenous deposits (CHOI & HARIYA, 1992), while the ΣREE values of the hydrothermal oxi­de­deposits­have­a­wider­range­(MILLS­et­al.,­2001;­ŞAŞMAZ­ et al., 2014). Formation environments display variability for Eu anoma- lies. The Eu value for seawater is 0.61 ppm, while the value is close to 7 ppm in hydrothermal deposits. Variations in Ce anoma ly are close to 0.17 for seawater and 1.03 in the continental crust (DANIELSON et al., 1992; MANIKYAMBA & NAQVI, 1995; MISHRA et al., 2006; MORIYAMA et al., 2008). Ferromanganese samples from the study area had an Eu anomaly of 0.88–48.10 (ave. 9.94). The Ce anomaly value was 0.02–0.88 (ave. 0.58). When­both­anomalies­are­assessed,­the­effect­of­the­mixing­of­ seawater­and­hydrothermal­fluids­on­mineralization­may­be­con- sidered. The positive Eu anomaly in mineralized samples is a typical feature of modern manganese hydrothermal deposits in the oceanic environment. Negative Ce anomaly shows the prese nce of oxic ocean water (WRIGHT et al., 1987; KOÇAK, 2020a, b). The REE data for mineralized samples in the study support the idea that manganese mineralization occurred as precipitation as a result of both hydrothermal solutions and mixing with seawater (DANIELSON et al., 1992; MANIKYAMBA & NAQVI, 1995; MISHRA et al., 2006; MORIYAMA et al., 2008). When the Ceanom values in the study area are noted, 15 sam- ples had values lower than -0.1, while 5 samples had values larger than -0.1. These values show the environment had both oxic and anoxic characteristics. In mineralized samples, the Y/Ho ratio was determined as 33.29. This ratio is higher compared to hydro- thermal solutions, so the presence of a hydrothermal source and continental derived environment may be suggested. The histogram for homogenization temperatures measured in­fluid­inclusion­studies­of­four­samples­is­presented­in­Fig.­9.­ Three­different­quartz­stages­were­identified­in­the­measured­ samples­and­there­are­3­different­data­intervals­on­the­histogram­ for­Th­ temperatures­measured­ in­fluid­ inclusions­ from­these­ stages. Accordingly, the distribution of data on the histogram in- dicates­3­different­solution­stages.­ Additionally, the eutectic temperatures for four samples are provided in Table 4. Accordingly, all samples had eutectic tem- peratures­equivalent­to­different­phases,­ranging­from­­33.8­to­ -49.9 °C. When these eutectic temperatures are compared with the­eutectic­temperatures­for­different­salt­compositions­given­by­ SHEPHERD et al. (1985) (Fig. 10), all measurement results show fluid­inclusion­composition­was­comparable­with­H2O-CaCl2- NaCl-FeCl2-MgCl2. While­the­salinity­for­Type­I­fluid­inclusions­varies­from­1.9­ to­14.7­wt.%­NaCl­equiv.,­Type­II­and­III­fluid­inclusions­had­ lower­salinity­values­of­1.9­to­5.1­wt.%­NaCl­equiv.­Accordingly,­ the­Th­salinity­trend­for­Type­I­fluid­inclusions­was­compatible­ with a dilution trend for hydrothermal solutions with surface so- lutions (Fig. 11). This trend indicates that solutions with the partly high­salinity­in­Type­I­fluid­inclusions­(may­have­a­magmatic­ source) mixed with solutions with low salinity (meteoric). In con- trast,­Type­II­and­III­fluid­inclusions­had­salinities­from­1.9­to­5.1­ wt.%­NaCl­equiv.­which­indicate­they­formed­under­the­effect­of­ meteoric solutions. G eo lo gi a C ro at ic a 302 Geologia Croatica 74/3 7. CONCLUSIONS 1.­ ­As­a­result­of­field­studies,­geochemical­and­petrographic­ investigations,­and­fluid­inclusion­studies,­mineralization­ may be considered to have formed in three stages. 2. Additionally, the formation occurred by ferromanganese mineralization precipitating in both oxic and anoxic environ- ments­with­hydrothermal­solutions­affected­by­mixing­with­ seawater. 3.­ ­According­to­fluid­inclusion­studies,­the­three­different­solu- tion stages of mineralization can be said to have tempera- tures­of­338­438­°C­for­the­first­stage,­269­317­°C­for­the­se­ cond stage, and 143-236 °C for the third stage. The calculated salinity­concentrations­were­particularly­high­for­Type­I­fluid­ inclusions­(1.9­14.7­wt.%­NaCl­equiv.)­and­lower­for­Type­II­ and­III­fluid­inclusions­(1.9­5.1­wt.%­NaCl­equiv.).­Decreas- ing salinity versus the Th temperature trend in Figure 11. indicates that mineralization formed from a mixture of mag- matic and meteorically derived solutions. 4. In the mineralized samples, the Y/Ho ratio (33.29) is higher compared to hydrothermal solutions, so the presence of a hy- drothermal source and continental derived environment may be suggested. 5. Apart from two samples, all the ore samples had a Sr/Ba ra- tio lower than 1 representing formation in a continental sedi- mentary environment for mineralization in the study area. 6. In the region, magmatism developed in the form of plutonic activity within crystalline massifs and as submarine volca- nism in the Upper Cretaceous and Middle Eocene periods. Later it is thought there was variation in ore minerals with the­effect­of­meteoric­waters.­In­the­study­area,­the­first­phase­ of­mineralization­with­three­different­phases­of­bands­and­ stockwork structure at the basalt-limestone contact and within limestones is thought to have formed with volcanic activity in the Middle Eocene period. 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