NSF workshop: Drilling, sampling, and imaging the depths of the critical zone

了解调节地球表面的化学，物理和生物过程在各种问题上都很重要，从评估人类时间尺度上的土壤可持续性，到了解地球长期气候演变中与天气相关的反馈。这些问题越来越多地在令人兴奋的“临界区”（CZ）的跨学科研究中得到解决。虽然CZ被认为延伸到自由循环地下水的最低限度，但大多数地下CZ研究都集中在景观中风化岩石和土壤的上部1-2 m左右。因此，深CZ（即，任何太深而难以用手获取和取样的东西）代表了流域水文学、地球生物学、地貌学、土壤科学和低温地球化学进步的一个重要前沿。研究深CZ的障碍之一是深度本身;风化层、孔隙沃茨和地下生物群很难就地表征，因为它们大多埋在难以进入的深度。解决深CZ研究的挑战将需要协调的调查，利用钻井，采样，监测和成像的地下的最新进展。该奖项将支持一个研讨会，旨在发展一个社区范围内，跨学科的共识，就如何克服深CZ研究的传统困难。该研讨会将汇集45人，包括CZ研究人员和近地表岩石学家，以及在钻井，取芯和钻孔仪器方面有经验的工程师。它利用了以下方面的机会：㈠越来越需要在深CZ研究方面取得进展，这是世界各地CZ科学家最近达成的共识所表达的; ㈡近地表地球物理学方面的最新进展，包括深层CZ成像和解释CZ结构方面的地球物理特性的改进技术;以及（iii）最近在美国建立一个正式的大陆科学钻探计划的新势头。为了取得成效，研讨会需要弥合差距，促进来自不同学科的科学家和工程师之间富有成效的新合作。

Understanding the chemical, physical, and biological processes that modulate Earth's surface is important across a diverse range of problems, from assessing soil sustainability over human timescales, to understanding weathering-related feedbacks in Earth's longtermclimatic evolution. Increasingly, these problems are being tackled in exciting, crossdisciplinary studies of the "critical zone" (CZ). Although, the CZ is considered to extend to the lowest limits of freely circulating groundwater, most subsurface CZ research hasfocused on just the upper 1-2 m or so of weathered rock and soil in landscapes. Hence the deep CZ (i.e., anything that is too deep to readily access and sample by hand) represents a crucial frontier for advances in watershed hydrology, geobiology, geomorphology, soilscience, and low-temperature geochemistry. One of the hurdles in studying the deep CZ is depth itself; regolith, pore waters, and subsurface biota are difficult to characterize in situ because they are mostly buried at difficult-to-access depths. Tackling the challenge of deep CZ research will require coordinated investigations that exploit recent advances in drilling, sampling, monitoring and imaging of the subsurface.This award will support a workshop designed to develop a community-wide, crossdisciplinary consensus on how to overcome the traditional difficulties of deep CZ research. The workshop will bring together 45 people, including CZ researchers and near surface geophysicists, as well as engineers with experience in drilling, coring and borehole instrumentation. It exploits the chance alignment of: (i) an increasing need for advances in deep CZ research, voiced in a recent consensus of CZ scientists from aroundthe world; (ii) recent advances in near-surface geophysics, including improved techniques for imaging the deep CZ and interpreting geophysical properties in terms of CZ architecture; and (iii) recently renewed momentum behind establishing a formal programof continental scientific drilling in the US. To be effective, the workshop will need to bridge gaps, fostering productive new collaborations among scientists and engineers from diverse disciplines.