Geology of the Karalar-Yesiller Area, 'Northwest Anatolia, Turkey GEOLOGICAL SURVEY BULLETIN 1461 Prepared in cooperation with the Maden Tetkik ve Arama Enstitilsu under the auspices of the Government of Turkey and the Agency for International Development, U.S. Department of State QE75 Geology of the Karalar-Yesiller Area, Northwest Anatolia, Turkey By RICHARD D. KRUSHENSKY, YAVUZ AKgAY and ERDOGAN KARAE&E GEOLOGICAL SURVEY BULLETIN 1461 Prepared in cooperation with the Maden Tetkik ve Arama Enstitusu under the auspices of the Government of Turkey and the Agency for International Development, U.S. Department of State An area of volcanic, metamorphic, and sedimentary rocks intruded, faulted, and mineralized in the Neogene UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1980 UNITED STATES DEPARTMENT OF THE INTERIOR CECIL D. ANDRUS, Secretary GEOLOGICAL SURVEY H. William Menard Director Library of Congress Catalog-card No. 78-606170 For sale by Superintendent of Documents, U.S. Government Printing Office Washington, D.C. 20402 CONTENTS Page Abstract 1 Introduction ___-___-_ _ 1 Location and accessibility of the area 1 Previous work __________________ 3 Purpose and method of investigation ____ ______ _ - _ * ? Acknowledgments _________________________ _ _ __ __ * Geologic setting ______________________ __ ^ Stratigraphy _______________________________ 6 Pre-Tertiary System __________________________ 6 Metamorphic sequence of Kalabak _______ __ 6 Limestone of Ayakh _____________ 12 Hahlar Formation _____________________ 14 Type locality and distribution _________ 14 Lower member ________________________ 14 Middle member _______________________ 16 Upper member _______________________ 16 Limestone of Kojacal Tepe _______________ 19 Bagburun Formation _____________________ 21 Name and distribution ______________ 21 Petrography __________________________ 21 Contacts and age ______________________ 23 Tertiary System __________________________ 24 Hallaslar Formation ________________________ 24 Name and distribution _______________-___ 24 Description ________________________ 25 Petrography ________________________ 28 < Contacts and age ______________________ 30 Dede Tepe Formation ________________________ 30 * Name and distribution ________________ 30 Lower part ___________________________________ 31 Upper part ___________________________ 33 Atypical ash-flow tuff _____________________ 33 Lava unit ___________________________ 34 »- Petrography _______________________ 34 Contacts and age ______________________ 35 : Lake beds _ _ _________________ 35 Quaternary System ____________________________ 37 Alluvium ________________________________ 37 Landslide debris _______________________ 38 Intrusive rocks ______________________________ 38 Serpentinized dunite-peridotite ____________________ 38 Granodiorite-quartz monzonite ____________________ 41 T- iii IV CONTENTS Page Intrusive rocks Continued Granitic pegmatite ---__--________ 43 Quartz latite stocks ________________ _______ _____ 44 Rhyodacite stocks ____________________________ 46 Contact metamorphium _________________ 47 Structural geology _____________________ 49 Folds ______________________________________ 50 Faults __________________________________ 51 Kocacal Tepe thrust ________________ _ 51 High-angle normal faults ______________ 53 Geologic history ___________________________ ___ 54 Economic geology _________________________ _ 56 Hematite and magnetite deposits _______________ _ ___ 56 Egmir deposits _______________^____ 56 A§agidamlar deposit ___________-__-_ 57 Atizi Mvk. deposits _____________-__-_ 59 Base-metal deposits _______________- ___- 59 Atizi Mvk. deposit ____________________ 61 Kelkiran deposit _______________________ 61 Culfa Cukuru deposit _____________________ 61 Hahlar deposit ___________________________ ________ 62 Molybdenite ________________________________-- 63 Stibnite and cervantite _______________________ 63 Gold _________________________________________ 64 Description of type sections _______________________ 65 References cited _______________________________________ 71 ILLUSTRATIONS Page PLATE 1. Geologic map and sections of the Karalar-Ye§iller area (Bahkesir I 18 Ci, d, dz, and da quadrangles), north­ west Anatolia, Turkey _______________In pocket FIGURE 1. Index map of northwestern Turkey showing the loca­ tions of major geographic features and the Karalar- Ye§iller area _______________________ 2 TABLES Pagie TABLE 1. Analyses of the Hallaclar Formation __________ 27 2. Partial semiquantitative spectroscopic analyses of un- altered and altered andesitic and dacitic lava flows from the Halla?lar Formation _____________ 28 3. Analyses of the Dede Tepe Formation ___________ 32 CONTENTS V Page TABLE 4. Analyses of serpentinized dunite stocks in the d2 quad­ rangle ____________-_________________ 39 5. Analyses of specimens from the granodiorite-quartz monzonite batholith and the granitic pegmatitic stock__ 43 6. Analyses of specimens from the Dereoren and Sulutas. Tepe stocks _________________________ 45 7. Partial semiquantitative spectroscopic analyses of sam­ ples from mineralized areas in and near the Bahkesir I 18 Ci, c<, ds, and d3 quadrangles ______ ______ 60 8. Fire assay-atomic absorption analyses of specimens from the map area, Turkey ______________ 64 S I 33 /*»«i /"»/ > 82 35IOSU9 1/40 2166; GEOLOGY OF THE KARALAR-YE£ILLER AREA, NORTHWEST ANATOLIA, TURKEY By RICHARD D. KRUSHENSKY, YAVUZ AK^AY,* and ERDOGAN K.ARAEGE1 ABSTRACT Rocks cropping out in the Kalabak-Yesiller area (Bahkesir I 18 quad­ rangle) of western Turkey consist of the following in ascending order: (1) phyllite, marble, schist, and metaclaystone of probable Precambrian or Cambrian age; (2) limestone of middle Permian age; (3) sandstone and shale of Late Triassic age; (4) limestone of Late Jurassic age; (5) ande- sitic, dacitic, and rhyodacitic volcanic rocks-of Neogene age; (6) lacustrine sandstone and conglomerate of probable Neogene age; and (7) alluvium of Holocene age. The section is intruded by serpentinized dunite stocks of probable Late Permian age, and intruded and locally metamorphosed by a granodiorite-quartz monzonite batholith and stocks of rhyodacite and quartz latite of Neogene age. Two periods of folding and a period of thrusting and a later period of normal faulting are apparent even though no major folds have been recognized in the mapped area, and only a few folds can be traced for more than a few hundred meters. The first period of folding, probably during the mid­ dle Permian, gave rise to east-west oriented folds in the regionally meta­ morphosed sequence. A second period of folding gave rise to northeast- trending folds in the sandstone-shale sequence and possibly similarly oriented folds in the metamorphic sequence. Paleontologic and structural evidence indicates that the limestone units were later moved into the area as low-angle thrust sheets or as gravity slides, probably after the Jurassic. The formation of extensive northeast-trending normal faults and the min­ eralization of these faults by hematite, galena, sphalerite, chalcopyrite, and stibnite-cervanite followed thrusting and accompanied or shortly followed the intrusion of the batholith and related stocks. INTRODUCTION LOCATION AND ACCESSIBILITY OF THE AREA The mapped area, covering about 600 km2, lies in the province of Bahkesir in the Biga Peninsula of northwestern Turkey, ap­ proximately 210 km southwest of Istanbul. It is southeast of Qanakkale. It comprises the Bahkesir I 18 c,, c4, d2, and d:J quad- 1 Maden Tetkik ve Arama Enstitiisii. r» Ku« Golu tt ,J-x Ulubat Golu Burea > s: o » H3 w 25 H O £ > FIGURE 1. Index map of northwestern Turkey showing the locations of major geographic fea­ tures and the Karalar-Ye§iller area (Balikesir I 18 Ci, C4, d2 and d3 quadrangles). INTRODUCTION 3 rangles (fig. 1), and forms a block bounded by lat 39°30'00" and 39°45'00" N. and by long 27°07'30" and 27°22'30" E. The major east-west highway 62 crosses the area and connects Bahkesir, 45 km east of the mapped area, with the city of Edremit, 7 km west of the area. From this highway, all-weather gravel-surfaced or dirt roads lead to the principal villages in the northern half of the d3 quadrangle, the northern quarter of the c4 quadrangle, and the western half of .the d2 quadrangle. Other areas are serviced by a few dirt-surfaced oxcart roads, generally passable in. the dry season by 4-wheel-drive vehicles. Extensive areas, including some villages, are reached by foot trails only. Most of the area of the quadrangles lies within the Kalkim and Edremit National Forests. Deforested upland areas and the na­ tional forests are commonly used for grazing. Perhaps 20 percent of the mapped area is used for growing olives, fruit, grain, and vegetables. The mapped area consists chiefly of well dissected but essen­ tially youthful upland, cut on the western side in the d3 quadrangle by the alluvium-filled valley of the Havrancayi (<jay, stream). Broad ridges that have well-integrated drainage characterize the area. Flat, undissected uplands are restricted to small areas on the southern margin of the d., quadrangle, to Kocagal Tepe (tepe, hill) in the north-central part of the d3 quadrangle, and to the southeast corner of the d2 quadrangle. Relief is only moderate, the most extreme being about 550 m between 1,007 m at the top of Ayi gedik (gedik, gap) and 450 m at Ba§ Koprti (koprii, bridge) in the northwestern quarter of the d2 quadrangle. Similar relief over a shorter lateral distance is present in the southeastern