RUI: Thermal Consequences and Textural Signatures of Reinjection in Mafic Sills

正如火山有喷发和休眠的交替时期一样，火成岩侵入体也有注入和结晶的交替时期。 这项研究将提供一个更好的了解侵位过程及其影响的侵入系统，特别是在基性岩床。 该研究将确定岩浆再注入部分结晶系统的诊断物理和化学特征，以及可用于确定其时间和热条件的再注入层位的具体结构特征。 识别镁铁质系统中再注入的诊断标准将允许在其他侵入体中积极识别这一过程，并将对岩浆房形成和演化的模型产生重要的约束。 此外，有待开发的数据（结构、成分和矿物学剖面）将广泛分布，作为开发和测试岩石学假设的资源，本研究的主要目标是通过一个连续的岩心剖面，通过一个可调的岩坎，确定回注事件的详细特征（黑鲟鱼）来自安大略的尼皮贡。 岩相学数据将包括模态矿物学、结构（晶体粒度分布）和组构（排列因子）。 地球化学数据将包括大块岩石的主要和微量元素化学和矿物成分。 初步结果已被用来初步确定的位置和影响的几个回注事件的黑鲟鱼窗台。 该项目将记录这些地点周围的细微变化，并确定其他潜在回注区的位置和特征。 这些结构和成分的变化将提供一套离散的标准，可用于证明和记录的存在，在岩浆系统中的回注层位。 数值冷却模型，然后将与纹理观测和MELTS建模集成，以提供黑鲟鱼岩床的就位历史的定量约束，包括个人补给事件的时间和空间分布。

Just as volcanoes have alternating periods of eruption and repose, igneous intrusions can also have alternating periods of injection and crystallization. This study will provide a better understanding of the emplacement process and its effects in intrusive systems, specifically in mafic sills. The study will identify the diagnostic physical and chemical signatures of magma reinjection into a partially crystalline system and the specific textural characteristics of a reinjection horizon that can be used to determine its timing and thermal conditions. Diagnostic criteria for recognizing reinjections in mafic systems will allow this process to be positively identified in other intrusions and will place important constraints on models for magma chamber formation and evolution. In addition, the data to be developed (texture, composition, and mineralogy profiles) will be widely distributed as a resource for developing and testing petrologic hypotheses, and for recognizing additional processes beyond those specifically addressed in this study.The primary goal of this study is to define the detailed signature of reinjection events using a continuous drill core profile through a diabase sill (the Black Sturgeon sill) from Nipigon, Ontario. Petrographic data will include modal mineralogy, textures (crystal size distributions), and fabric (alignment factor). Geochemical data will include bulk-rock major and trace-element chemistry and mineral compositions. Preliminary results have been used to tentatively identify the positions and effects of several reinjection events in the Black Sturgeon sill. This project will document the fine-scale variations around these sites and locate and characterize other potential reinjection zones. These textural and compositional variations will provide a set of discrete criteria that can be used to demonstrate and document the existence of reinjection horizons in magmatic systems. Numerical cooling models will then be integrated with textural observations and with MELTS modeling to provide quantitative constraints on the emplacement history of the Black Sturgeon sill, including the timing and spatial distribution of the individual replenishment events.