Version 1
: Received: 26 December 2023 / Approved: 10 January 2024 / Online: 10 January 2024 (09:50:03 CET)
How to cite:
KIRAY, D.; Cengiz, O. Petrography and Geochemistry of Hydrothermal Alteration at the Low Sulphidation Epithermal Kestanelik Au Deposit, Biga Peninsula, Nw Turkey. Preprints2024, 2024010779. https://doi.org/10.20944/preprints202401.0779.v1
KIRAY, D.; Cengiz, O. Petrography and Geochemistry of Hydrothermal Alteration at the Low Sulphidation Epithermal Kestanelik Au Deposit, Biga Peninsula, Nw Turkey. Preprints 2024, 2024010779. https://doi.org/10.20944/preprints202401.0779.v1
KIRAY, D.; Cengiz, O. Petrography and Geochemistry of Hydrothermal Alteration at the Low Sulphidation Epithermal Kestanelik Au Deposit, Biga Peninsula, Nw Turkey. Preprints2024, 2024010779. https://doi.org/10.20944/preprints202401.0779.v1
APA Style
KIRAY, D., & Cengiz, O. (2024). Petrography and Geochemistry of Hydrothermal Alteration at the Low Sulphidation Epithermal Kestanelik Au Deposit, Biga Peninsula, Nw Turkey. Preprints. https://doi.org/10.20944/preprints202401.0779.v1
Chicago/Turabian Style
KIRAY, D. and Oya Cengiz. 2024 "Petrography and Geochemistry of Hydrothermal Alteration at the Low Sulphidation Epithermal Kestanelik Au Deposit, Biga Peninsula, Nw Turkey" Preprints. https://doi.org/10.20944/preprints202401.0779.v1
Abstract
This study identifies the facies and degrees of hydrothermal alteration related to the low sulphida-tion epithermal Kestanelik Au deposit in the Biga Peninsula metallogenic province through petro-graphic studies and analysis of geochemical characteristics, such as mass changes, molar element ratios, and alteration indices. The gold mineralization is located in silicified zones containing veins and stockwork veinlets of quartz. These zones are found within the Permian-Upper Cretaceous aged Çamlıca basement metamorphics and Eocene aged Kestanelik granodiorite of the Karabiga Massif on the Biga Peninsula. The mineralization is influenced by tectonic structures such as quartz veins and faults. In the Kestanelik Au deposit, common hydrothermal alteration occurs mainly in the metamorphics and granodiorite, and less often in volcanic rocks. Based on miner-alogical and geochemical studies conducted on altered samples, four different alteration facies were defined as silicic, sericitic, argillic and propylitic, which show remarkable differences in the behaviour of REE, Si, K, Al, Na and Ca elements. The characterization of rocks subjected to hy-drothermal alteration that are most influenced by diverse K metasomatism with the largest K gains and losses of Na-Ca, is illustrated by molar element ratio plots. Depending on the severity of K-metasomatism, gold mineralization rises with increasing K trends towards gold ore veins. In the Kestanelik Au field, the alteration types of argillic, sericitic, propylitic and adularia from the alter-ation zones enclosing the Au ore veins, were revealed by the alteration index and chlo-rite-carbonate-pyrite index. Mass changes in the altered rocks indicate that there are gains in Si, K, Al, and losses in Na and Ca with the increasing intensity of alteration towards the Kestanelik ore veins. The results confirm the presence of silicic and K-metasomatic (sericite and argillic) propylit-ic (Fe-rich chloride) alteration zoning extending from the inner regions to the outer regions, which characterize the epithermal ore systems. It has been revealed from the data obtained in this study that the intensity of potassium metasomatism that occurs in acidic rocks is greater than that found in intermediate and mafic rocks. The hydrothermal fluids that cause alteration in Kestanelik Au mineralization and host rocks had low contents of REE due to REE mobilization, and the kaolini-zation of feldspars and micas, and the chloritization of biotite and feldspars, may cause negative Eu anomalies.
Keywords
Biga Yarımadası; düşük sülfidasyonlu epitermal tip; hidrotermal alterasyon; değişiklik indeksleri; kütle değişimi; molar element oranı; REE hareketliliği
Subject
Engineering, Other
Copyright:
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
