THE PRELIMINARY RESULTS ON THE KAOLINISATION OF TERTIARY VOLCANIC ROCKS IN THE BIGA PENINSULA (LAPSEKI-ÇANAKKALE), TURKEY

7th International Scientific Conference - SGEM2007, www.sgem.org, SGEM2007 Conference Proceedings/ ISBN: 954-918181-2, June 11-15, 2007

ABSTRACT

This study presents preliminary results of our study on the kaolinisation of
Tertiary magmatic units in the Biga Peninsula.
Volcanic and intrusive rocks of Tertiary age crop out in the vicinity of the
Harmancık and Üçpınar villages of Çanakkale country, Lapseki town. Volcanic
rocks consist of andesites, basalts and rhyolites, whereas intrusive rocks consist
of granitic plutons. The granitic intrusions cut the volcanic rocks. Kaolin
deposits appears to have formed within the andesitic rocks.
The kaoline deposit is located at nearly 3km northeast of Üçpınar village.
Outcrops of the deposit extends along a north-south trend with a width of 200-
250 m and a length of 600-700 m, reaching 10-15 m in thickness.
The presence of clays minerals accompanied with feldspars and kaolinite
indicates that the solutions from which the clay minerals precipitated were
enriched in some alkali and alkali-earth ions. This implies weak kaolinisation.
Besides, sudden and sharp temperature fluctuation of the solution due to
seasonal rainfall seems to have prevented mobile silica movement upwards and
resulted high amount of finely dispersed α-quartz(SiO2>75%) within the kaolin
deposits. And as a results, the dissolved silica did not replace and silicify the
main rocks and therefore, a “silica-gossan” did not develop. This can also be
considered as another evidence for weak kaolinisation.
We argue that the kaolinisation within the study area was formed by
hydrothermal fluids circulating through the faults.

Keywords: Kaolinite, Hydrothermal fluid, Lapseki.