|کد مقاله||کد نشریه||سال انتشار||مقاله انگلیسی||ترجمه فارسی||نسخه تمام متن|
|5786290||1640479||2017||22 صفحه PDF||سفارش دهید||دانلود رایگان|
- Geochemical signals of fluid flow through fractured carbonate rocks are reported.
- The Turkish North Anatolian Fault (Niksar portion) does not record deep fluids.
- Calcite veins record events unrelated to their active plate boundary position.
- Ion microprobe Î´18OPDB transects across calcite veins show fine-scale variations.
- Mineralizing fluid that reproduces fluid inclusion T has Cretaceous brine Î´18OSMOW.
Six limestone assemblages along the North Anatolian Fault (NAF) Niksar pull-apart basin in northern Turkey were analyzed for Î´18OPDB and Î´13CPDB using bulk isotope ratio mass spectrometry (IRMS). Matrix-vein differences in Î´18OPDB (â2.1 to 6.3â°) and Î´13CPDB (â0.9 to 4.6â°) suggest a closed fluid system and rock buffering. Veins in one travertine and two limestone assemblages were further subjected to cathodoluminescence, trace element (Laser Ablation Inductively Coupled Plasma Mass Spectrometry) and Î´18OPDB (Secondary Ion Mass Spectrometry, SIMS) analyses. Fluid inclusions in one limestone sample yield Th of 83.8Â Â±Â 7.3Â Â°C (Â±1Ï, mean average). SIMS Î´18OPDB values across veins show fine-scale variations interpreted as evolving thermal conditions during growth and limited rock buffering seen at a higher-resolution than IRMS. Rare earth element data suggest calcite veins precipitated from seawater, whereas the travertine has a hydrothermal source. The Î´18OSMOW-fluid for the mineralizing fluid that reproduces Th isÂ +2â°, in range of Cretaceous brines, as opposed to negative Î´18OSMOW-fluid from meteoric, groundwater, and geothermal sites in the region and highly positive Î´18OSMOW-fluid expected for mantle-derived fluids. Calcite veins at this location do not record evidence for deeply-sourced metamorphic and magmatic fluids, an observation that differs from what is reported for the NAF elsewhere along strike.
Journal: Journal of Structural Geology - Volume 101, August 2017, Pages 58-79