İznik-Mecidiye (Bursa) bölgesinde eosen volkanitlerindekikuvars damarlarına bağlı gelişen cevherleşme potansiyelinin belirlenmesi
Determinatin of the mineralization potential of quartz veins in eosen volcanics of the Iznik-Mecidiye (Bursa) region
Yazar: FATMA KALELİ
Danışman: DOÇ. DR. MUSTAFA KUMRAL
İstanbul Teknik Üniversitesi / Fen Bilimleri Enstitüsü / Jeoloji Mühendisliği Ana Bilim Dalı
Derece: Yüksek Lisans, 2018
Konu: Jeoloji Mühendisliği = Geological Engineering

Özet:
İnceleme alanının temelinde Permiyen-Triyas yaşlı metamorfik kayaçlar
bulunmaktadır. Bu temel üzerine açısal uyumsuzlukla Üst Kretase yaşlı sedimanter
kayaçlar gelmektedir. Başlıca çamurtaşı, şeyl ve kumtaşından oluşan birim Kızılağaç
Tepe ve Pilav Tepe civarında yüzlek vermektedir. Bu birimler üzerine ise açısal
uyumsuzlukla Eosen yaşlı volkanitler gelmektedir. Mecidiye ve civarında geniş
alanlarda yüzlek veren volkanitler yer yer eğim atımlı faylar ile kesilmektedir.
İnceleme alanında bulunun Eosen volkanitleri (Kızderbent volkanitleri) kuzey, orta
ve güney olmak üzere üç zonda görülmektedir.
Mecidiye bölgesinde yer alan volkanikler bazalttan dasite kadar değişen bileşimdeki
kayalardan oluşmaktadır. Bu birimler formüllerinde su içeren ve içermeyen mafik
mineralleri kapsamalarına göre "sulu" ve "susuz" seri olmak üzere iki toplulukta
sınıflandırılmıştır. Sulu seriye ait lavlar mafik mineral olarak klinoproksen, amfibol
içerirler. Susuz seriye ait lavlar ise mafik mineral olarak piroksen içermektedirler.
Eosen volkanitleri içerisinde gözlenen fay ve eklem düzlemleri boyunca kuvars
damarları gözlenmiştir. Bu kuvars damarları boyunca opak minerallere ve
alterasyonlara rastlanmıştır. Hidrotermal çözeltilerden etkilenmiş Kızderbent
volkanitlerinde pirit ve kalkopirit gibi sülfitli; manyetit, hematit ve götit gibi oksit ve
hidroksitli mineraller belirlenmiştir.
Jeokimyasal sonuçlar kayaçların bazalttan dasite kadar değişen geniş bir aralıkta
olduğunu ve bunların kalkalkalen ve yüksek potasyumlu kalkalkalen nitelikte
olduğunu göstermektedir. Kayaçların N-MORB'a ve ilksel mantoya göre normalize
edilmiş örümcek diyagramlarında geniş iyon yarıçaplı elementler (LIL) açısından
(Sr, Rb, K, Ba, Th) bir zenginleşme gözlenirken, HFS (Ta, Nb, P) elementler
açısından ise tüketilme ve normalize edilmiş MORB çizgisine göre bir paralellik
görülmektedir.
Yapılan Y-Sr/Y ve (Yb)n-(La/Yb)n diyagramlarında Eosen volkanitleri klasik yay
serileri alanlarında yoğunlaşmaktadır. Adakitik alanlara da yer yer düşen örneklerde
genel eğilim volkainazmanın normal yay serisi alanlarında olduğunu göstermektedir.
Kayaçların özellikle yaygın bir şekilde silisleştiği zonlarda görülen Au anomalisi
(0.109 ppm) ve sahada pirit-kalkopirit minerallerinin varlığı, hidrotermal alterasyona
işaret etmektedir. Hidrotermal alterasyon sonucu kayaçta meydana gelen mineralojik
ve kimyasal değişimleri belirlemek amacıyla çeşitli alterasyon indeksleri
kullanılmıştır. Volkanitlerde görülen en yaygın ayrışma serisitik ayrışmadır.
Kel Tepe kuzeyinde gözlenen KB-GD uzanımlı eğim atımlı fay zonu ve civarında
gözlenen süreksizlik düzlemlerinde kuvars damarları yaygın olarak gözlenmektedir.  Bu damarlar boyunca pirit ve eser miktarda kalkopirit gözlenmektedir. Bu bölgede
yapılan jeokimyasal analiz çalışmaları sonucunda V anomalisi ile birlikte W, Zn ve
Cu anomalileri görülmektedir.
Yapılan laboratuvar ve saha çalışmaları sonucunda bölgede Eosen volkanitleri
içerisinde damar tipi hidrotermal cevherleşmenin görüldüğü ve damar kalınlıklarının
sınırlı olduğu belirlenmiştir. Daha çok damarlarda pirit ve nadiren kalkopirit
gözlenmektedir. Bölgede kuvars damarlarının volkanitlerde damar şeklinde
gözlenmesi cevherleşmede kırık sistemlerinin etkili olduğunu göstermektedir.

Abstract:
Armutlu Peninsula is located in Armutlu-Almacık Zone. The Armutlu Peninsula,
which is limited to the İstanbul-Zonguldak zone in the north, the Sakarya continent
in the south and the branches of the North Anatolian Fault are are divided into three
as the north, middle, and south zones. Today, these three zones are limited by the
North Anatolian Fault. The North Zone consists of the Armutlu metamorphic
assemblage and overlying the Late Cretaceous-Tertiary cover units. The middle zone
is predominantly dominated by 2 tectonic units. These units are the İznik
Metamorphic Community and the Gevye Metaophiolite. The northern and middle
zones are overlain by Late Mesozoic-Late Tertiary units. The southern zone includes
the Sakarya continent units.
The study area (İznik-Mecidiye) is located to the south east of the Marmara Region,
to the north-east of the Iznik Lake. Iznik district is connected to Bursa province and
is 85 km away.
On the basis of the study area, Permian-Triassic metamorphic rocks are present.
Upper Cretaceous sedimentary rocks are unconformably overlain by this basement.
The unit, which is mainly composed of mudstone, shale and sandstones, forms
around Kızılağaç Hill and Pilav Hill. The Eocene volcanics are unconformably
overlain by these units. The volcanics which are exposed in large areas around
Mecidiye are cut by slope-slip faults. The Eocene volcanics (Kızderbent volcanics)
in the study area can be seen in three zones as north, middle and south.
This work was carried out by field, laboratory and office work. A geological map of
an area of approximately 30 km2
remaining on the G23-d3 map of Bursa with a scale
of 1/25000 is made. A total of 50 samples are collected at each location where
observations were made, representing lithology, for mineralogical, petrographic and
chemical analyzes. Laboratory studies include chemical analyzes and mineralogicalpetrographical surveys. Office work indicates interpretation of all data obtained,
collection under specified headings, forming of graphs and tables, and thus passing
all data and writing stage.
The mineralogical and textural characteristics of the Eocene volcanic rocks were
determined. As a result of polarizing microscopy, rocks were classified according to
their modal ratios and phenocrystalline and dough contents are determined.
The volcanics in the Mecidiye region are composed of rocks ranging from basalt to
dasite. This units are divided into two main groups according to their mineralogical
features (according to their formulas and they contain mafic minerals with water or
not); as anhydrous lava series and hydrous lava series.The lava from hydrous series
are composed of andesitic and trachy-andesitic rocks which contain clinoproxene and 
xx
amphibole as mafic minerals. Anhydrous series are represented by basaltic and
basaltic andesitic rocks. This rocks are made by plagioclase + clinopyroxene +
opaque minerals.
Along the fault and joint planes within the Eocene volcanics, quartz veins observed.
Opaque minerals and alterations were found along these quartz veins. Kızderbent
volcanics affected by hydrothermal solutions include sulphide such as pyrite and
chalcopyrite; minerals with oxide and hydroxid such as magnetite, hematite and
goethite were determined.
In order to determine the geochemical properties of 60 samples taken from the study
area, major, trace and rare element analyzes are examined in the geochemistry
laboratory (ITU-JAL) in Geochemistry Department of Minin Faculty of Geological
Engineering Department. Diagrams were created according to the results of the
chemical analysis of the selected 40 samples and the properties of the samples were
determined. Detailed data are obtained by using ICP-MS and XRF devices.
The geochemical results show that the rocks are in a wide range ranging from basalt
to dasite and they are calcalkaline and high potassium calc-alkaline. While an
enrichment is observed in spider diagrams normalized according to N-MORB and
primary mantle in terms of elements of wide ion radius (LIL) (Sr, Rb, K, Ba, Th), in
terms of HFS (Ta, Nb, P) elements there is depletion and there is a parallelism to the
normalized MORB line. Nb, Th, Ti, and P elements show a relatively negative
anomaly while Pb shows positive anomaly. These data are characteristic for the
subduction zone and post-collision lava. The negative Eu anomaly seen in the
diagrams reflects the effects of a shell-based addition to the mafic magma, or it is a
reduction caused by crystallization of plagioclases.
The overall result obtained from all tectonic divergence diagrams reveals that the
Eocene volcanics are the end products of the subduction.
The Harker diagrams were used in order to compare / differentiate the magma series
with SiO2, which is a simple but very useful method. Thanks to the trends obtained
from these diagrams, it is possible to comment on issues such as cold crystallization,
magma mixture and partial melting.
The general characteristics observed in the Harker diagrams are as follows: Al2O3
MgO, CaO, TiO2 ve Fe2O3 show a tendency to decrease against increasing silica
value. This negative trend shows that the main oxides are consumed in magma and
enter the crystal structure. These trends observed in diagrams can be interpreted as
the rocks coming from the same magma.
The Au anomaly (0.109 ppm) and the presence of pyrite-chalcopyrite minerals in the
zones where the rocks are widely silicified, indicate the hydrothermal alteration.
Various alteration indices have been used to determine the mineralogical and
chemical changes occurring in the rock as a result of hydrothermal alteration. The
most common alteration in volcanics is sericitic alteration.
Quartz veins are widely observed in discontinuity planes which is seen in NW-SE
extending slope fault fault zone and north of Kel Hill. Pyrite and trace amounts of
calcopyrite are observed along these veins. As a result of geochemical analysis
studies performed in this region, W, Zn and Cu anomalies are seen with V anomaly.
As a result of the laboratory and field studies, it is determined that the vein type
hydrothermal mineralization is observed within the Eocene volcanics and the vein
thickness is limited. Pyrite and rarely chalcopyrite are observed in the veins. The
observation of quartz veins in volcanics in the region shows that the fracture systems
are effective in mineralization.