Using accessory minerals of probes of crustal processes

我未来五年的研究计划的目标是更好地了解通过辅助矿物如锆石、独居石、磷灰石和钛铁矿的化学和同位素变化记录的地球地壳过程。为了实现这一目标，我将利用原位示踪放射性同位素测量获得的结果，包括锆石中的Lu-Hf和独居石、磷灰石和钛矿中的Sm-ND；这些矿物的微量元素组成；以及U-Th-Pb年代学。这套全面的免费地理分析技术将被有效和高效地用于解决各种不同的地质问题，这些问题直到最近才共同成为可能。通过研究控制地壳化学和同位素变化的矿物尺度过程，我们可以帮助开发更强大的地壳随时间演变的模型。作为Lu-Hf和Sm-ND研究的一部分，合成矿物将在高温下生长，掺入元素和元素的特定同位素，然后进行化学和结构表征。这些晶体将被用作锆石中的Hf和独居石、钛铁矿和磷灰石中的ND的同位素标准，用于放射性示踪同位素研究。然后，这些合成标准将被用于利用激光烧蚀多收集器电感耦合等离子体质谱对天然矿物进行更准确和准确的现场分析。未来五年要调查的一个领域包括花岗岩-下地壳捕虏体的连接，使用的是中生代下地壳捕捉体和来自加利福尼亚州东南部莫哈韦沙漠的花岗岩。该地区是研究花岗岩-源岩联系的理想地点，因为源区和可能相关的深熔熔体可以直接取样。意大利北部阿达梅洛岩基的后阿尔卑斯山英云闪长岩和相关岩石的源区也将作为与瑞士同事更大合作研究工作的一部分进行研究。第三个重点领域将探讨瑞典北部Norrbotten地区(如基律纳)的铁矿石、铜、金(IOCG)和铁矿石磷灰石(IOA)矿床及相关岩石的成因。

The objective of my research program over the next five years (and leading to the longer term ten-year time frame) is to gain a better understanding of the Earth's crustal processes recorded through chemical and isotopic variations in accessory minerals such as zircon, monazite, apatite, and titanite. To work towards that goal, I will utilize results obtained by doing in situ tracer radiogenic isotope measurements, including Lu-Hf in zircon and Sm-Nd in monazite, apatite, and titanite; the trace element compositions of those minerals; and U-Th-Pb geochronology. This comprehensive suite of complimentary geo-analytical techniques will be effectively and efficiently used to address a wide range of diverse geologic problems that collectively were not possible until recently. By studying the mineral-scale processes that have controlled the chemical and isotopic changes in the Earth's crust, we can help with the development of a more robust model for the evolution of the crust over time. As part of the Lu-Hf and Sm-Nd research, synthetic minerals will be grown at high-T, doped with elements and specific isotopes of elements, and then chemically and structurally characterized. These crystals will be used as isotopic standards for Hf in zircon and Nd in monazite, titanite, and apatite for radiogenic tracer isotope studies. The synthetic standards will then be used to obtain more precise and accurate in situ analyses of natural minerals using laser ablation multi collector inductively coupled plasma mass spectrometry. One area to be investigated over the next five years includes the granite-lower crustal xenolith connection using Mesozoic lower crustal xenoliths and granites from the Mojave Desert in SE California. This locality is ideal for studying the granite-source connection, as the source region and possibly related anatectic melts can be directly sampled. The source region of post-Alpine tonalites and related rocks from the Adamello batholith in northern Italy will also be studied as part of a larger collaborative research effort with colleagues in Switzerland. The third focus area will address the origin of iron ore, copper, gold (IOCG) and iron ore apatite (IOA) ore deposits and related rocks from the Norrbotten region (e.g., Kiruna) in northern Sweden.