Lithospheric structure and tectonics based on seismic reflection, refraction and other geophysical studies

北美的岩石圈(地球的坚硬外壳)在过去40亿年里发展起来，形成了我们现在看到的各种地质特征的拼贴。确定现在的岩石圈结构，以及它是如何在地质时期形成的，代表了关于“内部空间”的基本知识，这与对“外层空间”的知识一样重要。这种知识也有实际应用：对钻石、贱金属和石油公司有用的区域信息；以及地震发生的原因和方式。本申请中提出的三个项目提供了部分知识，主要基于受控震源地震方法。项目1将通过对可控震源反射剖面上的初至波应用最近开发的一种方法--波形层析成像，得出最上层地壳的速度结构，其分辨率比目前可能的更高。根据岩石类型对结果进行解释，并可用于改进对整个数据集的计算机处理。项目2力求定量描述岩石圈边界的特征并建立详细的模型，特别是地壳底部的莫霍面，以更好地了解岩石圈的发展和改造过程。生成具有代表性的边界模型，其中一些是基于物理模型，另一些是通过对观测数据的属性进行统计分析。计算了与观测数据相当的合成数据，并进行了比较。LITHOPROBE是加拿大备受赞誉的国家地球科学研究项目[www.litoprobe.ca]，该项目在22年后结束。根据加拿大各地的结果，项目3A将生成从太平洋到大西洋的6000公里长的岩石圈横断面，以及加拿大西北部和东北部的类似横断面。这些都表明了我国演变过程的复杂性。项目3B将总结加拿大是如何成为目前所代表的地质拼贴的。一系列与地质领域和构造过程有关的插图和文字将记录加拿大从大约40亿年前到现在的演变。

The lithosphere (the rigid outer shell of Earth) of North America developed over the past 4 billion years to generate the collage of geological features that we now see. Determination of present lithospheric structure, and how it formed over geological time, represent basic knowledge about "inner space" that is just as important as knowledge of "outer space". Such knowledge also has practical applications: regional information useful for diamond, base metal and petroleum companies; and why and how earthquakes occur. The three proposed projects in this application provide some of this knowledge, primarily based on controlled source seismic methods. Project #1 will derive velocity structure, with higher resolution than currently possible, for the uppermost crust through application of a recently developed method, waveform tomography, to first-arriving waves on vibroseis reflection profiles. Results are interpreted in terms of rock types and may be used to improve computer processing of the full dataset. Project #2 seeks to quantitatively characterize features and develop detailed models of lithospheric boundaries, particularly for the base of the crust, the Moho, to better understand the processes involved in lithospheric development and modification. Representative models of the boundaries are generated, some based on physical models and some through statistical analyses of the properties of observed data. Synthetic data equivalent to the observed data are calculated and comparisons are made. LITHOPROBE is Canada's highly acclaimed national Earth science research project [www.lithoprobe.ca], which is concluding after 22 years. Based on results from across Canada, Project #3A will generate a 6000-km-long lithospheric cross-section from the Pacific to the Atlantic oceans as well as similar cross-sections for NW and NE Canada. These demonstrate the complexity of the processes involved in the evolution of our country. Project #3B will develop a summary of how Canada became the geological collage that it currently represents. A series of illustrations and accompanying text relating to geological domains and tectonic processes will document Canada's evolution from about 4 billion years ago to the present.