Sub-bottom seismic profiler for geoarchaeological and palaeoenvironmental research

用于地质考古和古环境研究的海底地震剖面仪

• 批准号: RTI-2023-00409
• 负责人: Boyce, Joseph
• 金额: $ 8.18万
• 依托单位: McMaster University
• 依托单位国家: 加拿大
• 项目类别: Research Tools and Instruments
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=751246
• 关键词: Sub; bottom; seismic; profiler; geoarchaeological

NSERC RTI funding is requested for purchase of an Edgetech 3400 sub-bottom profiling (SBP) system. The sub-bottom profiler employs broad-band (2-16 kHz), frequency-modulated `chirp' sonar pulses to produce  detailed seismic images of the sediment stratigraphy in shallow lakes, lagoons and marine basins. The highly portable (26 kg) Edgetech 3400 system can be deployed from small survey boats (e.g. Zodiac inflatables) and produces high-resolution seismic records in shallow water environments (< 2 m). Seismic penetration of up to 50 m can be achieved in silt and mud and thin sediment layers (< 10 cm) resolved. The new Edgetech SBP equipment is urgently required to replace an obsolete seismic profiling system purchased in 2004. The new Edgetech 3400 SBP system will support multi-disciplinary geological and geoarchaeological research in the Great Lakes and the Mediterranean. In the Great Lakes, the NSERC-funded research will employ measurements of the physical and geochemical properties of lake sediments to better understand the frequency of large storm events in the lower Great Lakes over the past 8000 years. During large storm events, storm waves over top sandy beach barriers depositing distinctive overwash sand layers in coastal lagoons. Storm layers are also deposited in lakes by the flood discharge of rivers. These deposits ('tempestites') can be identified in sediment cores extracted from the lake bed based on their sedimentary characteristics (grain size, microfauna, magnetic properties) and geochemical composition. Radiocarbon dating of pollen in storm event layers provides a detailed chronological record of storms and extreme weather events. Sub-bottom seismic profiling of coastal lagoons with the Edgetech 3400 will allow mapping of the thickness and 3-dimensional arrangement of lagoon sediments and storm layers. The high-resolution lake sediment record will allow McMaster researchers to assess whether the frequency of storms has been different in the past, and whether variability in storminess is linked to climate variables, such as past changes in temperature and precipitation. These data are critical for evaluating predicted changes in storm frequency and will assist in the development of emergency and infrastructure planning for heavily populated areas of the Great Lakes that are at risk from severe weather.  In the Aegean, seismic profiling of nearshore coastal sediments will better resolve sea level changes, paleoshoreline positions and the potential locations of drowned prehistoric coastal settlements and ancient harbour sites. The sub-bottom profiler will provide 8 high-qualified personnel (HQP's) at McMaster and Brock University with critical hands-on skills and field experience in marine seismic survey methods, data processing and interpretation. These HQP skills are broadly applicable in geosciences research and currently in high demand by private and public sector employers.

要求NSERC RTI提供资金，用于购买Edgetech 3400海底剖面（SBP）系统。浅海底剖面仪采用宽带（2-16千赫）调频“啁啾”声纳脉冲，制作浅水湖、泻湖和海盆沉积物地层的详细地震图像。Edgetech 3400系统非常便携（26公斤），可以从小型勘测船（如Zodiac充气船）上部署，并在浅水环境（< 2米）中产生高分辨率的地震记录。在淤泥和泥浆中可实现高达50米的地震穿透，并可分辨薄沉积层（< 10厘米）。迫切需要新的Edgetech SBP设备，以取代2004年购买的过时的地震剖面系统。新的Edgetech 3400 SBP系统将支持五大湖和地中海的多学科地质和地质考古研究。在五大湖，NSERC资助的研究将采用湖泊沉积物的物理和地球化学性质的测量，以更好地了解过去8000年来五大湖下游大风暴事件的频率。在大风暴事件期间，风暴波越过顶部桑迪海滩屏障，在沿海泻湖中沉积独特的过冲砂层。河流的泄洪也会使风暴层沉积在湖泊中。这些沉积物（“风暴岩”）可以根据其沉积特征（粒度、微型动物、磁性）和地球化学成分，在从湖床提取的沉积物岩心中识别。风暴事件层中花粉的放射性碳年代测定提供了风暴和极端天气事件的详细年代记录。使用Edgetech 3400对沿海泻湖进行海底地震剖面测量，可以绘制泻湖沉积物和风暴层的厚度和三维排列图。高分辨率的湖泊沉积物记录将使麦克马斯特大学的研究人员能够评估过去风暴的频率是否不同，以及风暴的变化是否与气候变量有关，例如过去的温度和降水变化。这些数据对于评估风暴频率的预测变化至关重要，并将有助于为面临恶劣天气风险的五大湖人口稠密地区制定应急和基础设施规划，在爱琴海，近岸沿海沉积物的地震剖面将更好地解决海平面变化、古海岸线位置以及被淹没的史前沿海定居点和古代港口遗址的潜在位置。海底剖面仪将为麦克马斯特和布罗克大学提供8名高素质人员，他们在海洋地震勘探方法、数据处理和解释方面具有关键的实践技能和实地经验。这些HQP技能广泛适用于地球科学研究，目前私营和公共部门雇主的需求很高。