Collaborative Research: Canadian Northwest Seismic Experiment

加拿大西北实验（以下简称CANOE）将采用一个y形、48个站点的宽带地震阵列来解决固体地球演化中两个尚未解决的重大问题：大陆的组装和稳定，以及地球核幔边界（CMB）作为地幔柱的诞生地和俯冲板块的墓地的重要性。通过一系列与俯冲相关的碰撞事件，大陆从迅速稳定的核向外生长，在随后的数十亿年里几乎没有变形。这种稳定性可能是由于与克拉通构造有关的动态过程，但人们对其了解甚少。世界上绘制大陆构造地图的最佳地点是加拿大地盾的西北角，它的特点是从25 - 40亿年前的奴隶省（地球上已知最古老的岩石的所在地）到最近隆起的大落基山脉系统的北科迪勒拉。调查人员将在这一过渡期间部署宽带地震仪，西边的地震仪沿着阿拉斯加高速公路从不列颠哥伦比亚省的怀特霍斯到AB的埃德蒙顿，东边的地震仪从不列颠哥伦比亚省的纳尔逊堡到西北地区的耶洛奈夫。利用当地、区域和遥远的地震记录，研究人员将构建与科迪勒拉到克拉通转变相关的地幔和地壳的详细图像。通过记录太平洋盆地深处的地震，CANOE的部署还将提供最下层地幔地震结构的无与伦比的采样。90年代见证了一系列关于下地幔和CMB的新的和不寻常的发现，包括成分非均质性、部分熔融和各向异性地幔结构的证据，这些证据对地幔动力学过程具有重要意义。CANOE位于世界上绝大多数深层地震活动性的1200年以内，为更详细地研究下地幔提供了一个绝佳的机会。这包括对夏威夷下方的CMB无与伦比的覆盖，为测试这个热点原型的起源模型提供了一个极好的机会。实验结束后，所有数据将通过IRIS数据管理中心（www.iris.washington.edu）提供给社区。地震仪器将由IRIS pascal项目提供。该实验的一部分由加拿大岩石探测计划通过授予英属哥伦比亚大学资助

Gaherty-EAR0003404Revenaugh-0003746Garnero-0003745The Canadian Northwest Experiment (CANOE hereafter) will employ a Y-shaped, 48-station broadband seismic array to address two of the great unsolved problems in the evolution of the solid Earth: the assembly and stabilization of the continents, and the importance of the Earth's core-mantle boundary (CMB) as the birthplace of mantle plumes and the graveyard of subducted slabs. Constructed via a sequence of collisional events associated with subduction, continents grow outwards from nuclei that stabilize quickly, experiencing little deformation over the subsequent billions of years. This stability is presumably due to dynamic processes associated with craton construction, but is poorly understood. The best locale in the world for mapping continent construction is the northwestern corner of the Canadian shield, which is characterized by a progression from the 2.5-4 billion-year-old Slave province (home to the oldest known rocks on Earth) to the recently uplifted Northern Cordillera of the great Rocky Mountain system. The investigators will deploy broadband seismometers across this transition, with a western arm following the Alaskan highway from Whitehorse, BC to Edmonton, AB, and an eastern arm reaching from Fort Nelson, BC to Yellowknife, NWT. Using records of local, regional, and distant earthquakes, the investigators will construct detailed images of the mantle and crust associated with this cordillera-to-craton transition.By recording earthquakes from the far reaches of the Pacific basin, the CANOE deployment will also provide unsurpassed sampling of the seismic structure of the lowermost mantle. The 90's witnessed a parade of new and unusual discoveries about the Earth's lower mantle and CMB, including evidence for compositional heterogeneity, partial melting, and anisotropic mantle fabric that have strong implications for mantle dynamic processes. CANOE, situated within 120o of the vast majority of the world's deep seismicity, provides a remarkable opportunity to examine the lower mantle in greater detail. This includes unsurpassed coverage of the CMB beneath Hawaii, providing an excellent opportunity to test models of the genesis of this hotspot archetype.Following the experiment, all data will be made available to the community through the IRIS Data Management Center (www.iris.washington.edu). Seismic instrumentation will be provided by the IRIS PASSCAL program. A portion of the experiment is funded by the Canadian Lithoprobe program via a grant to the University of British Columbia.--