Jeoloji Mühendisliği Dergisi

ABSTRACT: Studies in the recent years have estabüshecl that the strontium laotoplc ratio» (8îSr/S6İr)measured in igneous rocks have considerable contributed to the attempts aiming to light up the genetteproblems of these rocks. In this paper, these studies are summarized, their appUeations to the Cenozolcvolcanic rocks In the Aegean and in West Anatolia are stated, and the genetic problems and mapnaicevolutions of these voloanles are discussed. The Sr lsotopic ratio measurements earned out in the PlioQuaternarY island are volcanic» found in the Aegean sea have revealed that this arc wleaiiism hasa much greater 8?Sr/86Sr content than those of other island arcs in the world, and that this ratio alsoshows differences locally from one point to another. On the lother hand, the Sr isotope measurement»conducted in the Cenozoie volcanic rocks of West Anatolia Imply that voieamsm in this region k notmonogenic, and that there is a mantle-crust relationship.

ABSTRACT: In the Avmlk aıea, apattte-rlch iron mm are toterbedl^d wîtti basic to İ&lfAe calo-alkaMne metmolmnâm (ca, 4Ä OMa) showing some well-preserved parphyritiô* spheruUttc and voîoaıüelastie texture»,They ar« intrudM by the Avnik and YaylÉ* graMttAï (ca. SÄO Ma). The toon ores and associated metavolcoiiù`s and granitoids are utioonfornmbly overlain by ntieaschtets and Permian marbles, which were foldedand metamorphosed during the Alpine orogeny The won ore bodies are banded, massive or âï»m mtoated M form and me located along the gmdatfionalcontact zone between the gneisses and the better-pre »rved parts of the metavoleanic sequenee. The vmmUve lonsdkkil oi^ zones ar© teaninated, 1-» millimeters to a few eenttmeters, and the banded ore zones showmagnetite-apatite lamination». The dissemtoated iron ot€» are re^onally widespread in til© metovolcaniçs, butusually are coneent^teâ adjecent to the massive ore zones.Magnetite, apatite and acttnolite are the dominant minerals to all ty^ s of depteit; accessory phases tolude feldspar» quartz, mÊm, diopside, hornblende, eroiàte and sphene, OMorite, tale, epMote, aHanite, eaMte, hematite, Mmenite and mtile are low- T retrograde minerals. Surface and near surface, magnetite eoneentmttons are always wtte â The final stage of alteration con»tet§ of a general toasformatton in togTOthite. Fluo^pattte was partly altered to hydroxy-fluorapattte and hyroxyapattte. The apatite-rich iron ares were initially formedj in a volcanic environment and it i* concluded thatthe ores formed from Immiscible Mquids which se^mted from magmas that underwent strong fraettonation,BEE data on coexisting apatite ana magnetite and on the associated metevoicamtes support this conclusion. Where the apattte-rfeh iron ores were intrudedby the AvMk granitoid, they were remobiiîzeâ to from»toekwork type veiiis of large magnetite, apatite and aotiaiolite crystals,

ABSTRACT: In the Sinop bankı, a sedinıeaıtary sequence with a thickness öl more than ten thousandsmotors has been developed during the lias-Quaternary tiinie iiitervaJ,Metamorphlc rocks of Boyabat fonu the basement of the bairfit, I®m a^eû Akgël formation unctmfor^mably overlies the basement, Bürnük formation, composed of red iconfrlomerategj overlies Ategol formattonwith an unoonfiarmity, Dumig1 Borger and Malm» a shallow marine environment has been presented Inthe area and the Akkaya Umestone formation lia« been deposited with Its platform-type carbonates,consisting of thick layer» and occasionally ancwing reef characteristics with abundant organJsınSt LowerCretaceous aged Çağlayan formation overMes Akkaya Limestones with anı unconformity, and consists ofturbldltic sandy Hmeatonej üandstane MterbeMed black^^ialè and marts. Which implies the presence of amarine environment. Bareness of iomûn and the abunclamca of pyrites Indicate the presence of a reduction` inthe environmental canditftms. At the end of Lower Cretaceou^ the area has been teçtonïcalïy upliftedagalnı. From the beginning »of the Santonlan, aiubsidënce restarted, During Bantonian and Oampanianfred colored cherty, mlcrltlc limestones, indicatttag` the peeiitaftiJes of a dteep marine environment, have beendeposited, At the end of Oampanian, the area has clearly acquired the chraeteriistîes of a goesyneline.The Yeimfliomy formatJcn, v/hich has been developed over Kapanbofazı formattottj Is of the volcanic flysehfacie», eon&Ssting of turbïclltic sandston-nisarl Interbedded tuff and tuffite alternattons, Th% unit isovertain by the Cankurtaran formatton, which is of Maastricntian, and which coniÄist of the alternation oftıırMdiâtic sondstone» inarf and shale tiiat have been formed in the flyseh fades,Th© Akveren jßarmation has a caieiturbfditle charaeter, and it is overlain by ttie turbidlttc red coloredAtbap formatton. Of sédimentation that has Initiated in Santonian had continued until Lower Eocenewithout any intennission, The area preserves its geosyncllne character during this time Interval, The Yenikonak formation overlies these deposits with an unconformity. Them all these units are overlain by theSlnop and Sarikum formations with an angular unconformity. Additionally, the Hamsaros formation ofthe region oansists of basaltic agglomerates^ volcanic tuffs, dykes and basalt lavas,

ABSTRACT: In thİA research the Serçeme creek and surrounding area in the NW of Erzurum have been Investigated. Producte of magmattsm comprises ultramafie rocks wMeh were intruded In the Upper Cretaceous and Tertiary boundary. They are compoaed of harzburgite and serpentïnite and Generally replaced by maJdmgcold fintnufon in to a tectonic Ipaumöary along which Lower Cretaceous Umaston© im thrusted on UpperCretaceous limestone, Serpenttnizatioii increases toward the nıargîns. miat situation pointe out that serpentinr/alion Is facilitated by tectonic agents. Serpentine minerals were studied by P.TÉA. method and It wasfound that those serpentinites contain mostly Mzardite. chry»ottle and chlinochrysotile but antig^rite.