Retromorph Reactions in Eclogites from Southern Carpathians - Case Study - Eclogites from the Upper Strei River Basin

For better understanding the PT conditions of the metamorphism engaged in the Variscan orogeny from the Southern Carpathians, but also a possible starting point for establishing a more accurate age of the similar bodies throughout the area,the study revolves around the retrograde mineral reactions. Although eclogite occurrences have been the subject of numerous studies throughout time, there is little knowledge regarding mineral reactions or the pressure-temperature range of the metamorphism. Of great importance, neo-formed minerals are indexes of fluid circulation and crystal contacts suggest the order of recristalization, therefore the PT path of the metamorphism. Through Microscope and Microprobe analysis the mineral reactions have been traced from the eclogite initial core of the body to the amphibolite exterior, marking key-points of the retromorphism. Using the retrograde reactions as a starting point and knowing the order of the newly formed phase minerals, it is possible to identify the pressure and temperatures of the metamorphism implied by the Variscan tectogenesis and to better understand the area, volume and depth under the influence of the geological event.