Three-dimensional subsurface modeling of mineralization: a case study from the Handeresi (Çanakkale, NW Turkey) Pb-Zn-Cu deposit

Demirela, Gökhan (Aksaray, Yazar)The main goal of 3D modeling studies in the mining sector is to address the complex geological, mineralogical, and structural factors in subsurface environments and detect the ore zone(s). In order to solve this complexity, use of quality data (e.g., a wide range of boreholes at regular intervals) is necessary. However, this situation is not always possible because of certain restrictions such as intensive vegetation, high slope areas, and some economic constraints. At the same time, with the development of computer technology, the unused and/or insufficiently considered data need to be gathered and reviewed. This assessment may lead to the detection of potential new zone(s) and/or could prevent unnecessary costs. In this study, the target area that was chosen had inadequate and unusable data, and we used the data as effectively as possible. The Handeresi area is located in the Biga Peninsula of northwestern Turkey. In this area, the Pb-Zn-Cu occurrences take place in carbonate levels of metamorphic rocks or at the fractures and cracks of other metamorphic rocks. The area is being explored actively now. In this study, using the borehole data, we attempted to model the subsurface of this area in 3D using commercial RockWorks2006® software. As a result, there were 3 ore zones that were seen intensively in this area. One of them indicates the area in which the adits are now operating. The others could be new potential zones

Geology and the alteration features of the Çataltepe (Lapseki- Çanakkale) Pb-Zn±Cu±Ag deposit

Demirela, Gökhan (Aksaray, Yazar)Biga Yarımadası’nın KB ucunda ve Çanakkale ili Lapseki ilçesi doğusunda yer alan Çataltepe Pb-Zn±Cu±Ag yatağı, Kretase yaşlı Çamlıca metamorfitlerinin mermerleri içinde ve onların diğer kayaçlarla olan dokanakları boyunca genellikle litolojik kontrollü olarak gelişmiş bir cevherleşmedir. Şu an aktif olarak üretim yapılan işletme alanında cevherleşmelerin genel doğrultu/eğimi mermer ve diğer metamorfitlerin genel doğrultu/eğimine uyumlu olup yaklaşık K40oB/40oKD’dur. Mikroskobik çalışmalar prograd evreye özgün granat ve piroksen minerallerinin varlığını ve bu minerallerin retrograd evrede karbonatlaşıp epidotlaştığını göstermektedir. Cevher mineralleri olarak kahverengi sfalerit, bal renkli sfalerit, galenit, kalkopirit, pirit, pirotin, valeriit, manyetit, hematit, markazit, arsenopirit ve limonit mineralleri izlenmektedir. Retrograd evre sırasında gelişen cevherleşmeler dokusal olarak masif dokulu cevherleşmeler ve saçınımlı dokulu cevherleşmeler olmak üzere iki gruba ayrılmakta ve masif dokulu cevherleşmeler saçınımlı dokulu cevherleşmeler tarafından kesilmektedir. Bu cevher minerallerine karbonat, klorit ve kuvars mineralleri eşlik etmektedir. Geç evre alterasyonlar başlıca manganoksit-hidroksit, limonit, karbonat ve kalsit mineralleri ile temsil edilmekte olup prograd ve retrograd evre alterasyonlarını maskelemektedir. Çalışmalar sırasında elde edilen veriler, Çataltepe Pb-Zn±Cu±Ag yatağının mermer-metakumtaşı/kuvarsit dokanakları boyunca ve esas olarak mermerler içinde bir magmatik etki ile evrimleşen cevherli çözeltilerden itibaren oluştuğuna işaret etmektedir. Ayrıca veriler, sıcaklık bakımından mezo-epitermal koşullarda oluşan distal Pb-Zn skarn yataklarına göre biraz daha sığ kesimlerde ortaya çıkmış epijenetik bir yatağı önermektedir.The Çataltepe Pb-Zn±Cu±Ag deposit, to the east of Lapseki (Çanakkale), in the northwestern part of Biga Peninsula, is hosted by marbles, and at the contact between marbles and other rocks of the Çamlıca metamorphics (Cretaceous). In the area, still under operation, the strike and dip of the mineralization are N40W/40o NE which is nearly parallel to schistosity of marbles and other metamorphic rocks. The microscopic investigations indicate that garnet and pyroxene minerals have been formed during prograde stages which were carbonatized and epidotized during the retrograde stage. The ore minerals are brown and honeyblende sphalerite, galena, chalcopyrite, pyrite, pyrrhotite, valleriite, magnetite, hematite, marcasite, arsenopyrite and limonite. The textural characteristics are suggestive of two subsequent mineralization at the retrograde; massive and disseminated ore, and the former is always cut by the latter. The ore mineral assemblage is accompanied by carbonate, chlorite and quartz. The late-stage alterations which are represented by manganese oxide-hydroxide, limonite, calcite and quartz, mask the prograde and retrograde stage alterations. Our data indicate that the Çataltepe Pb-Zn±Cu±Ag deposit was formed by ore-bearing solutions circulating particularly within marbles and along the marble-metasandstone/quartzite contacts. The data also favors an epigenetic origin for formation of the deposit under meso-epithermal conditions in areas relatively shallower than distal Pb-Zn skarn deposit