An Evaluation of the Long-Term Stagnancy of Porewater in the Neogene Sedimentary Rocks in Northern Japan

<div>Depth profile of <sup>4</sup>He concentration in the Koetoi and Wakkanai formations plots with open circle: significant amounts of bubbles were observed on the surface of the core during the sampling procedure.</div>

Geofluids

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Figure 5

Figure 5: An Evaluation of the Long-Term Stagnancy of Porewater in the Neogene Sedimentary Rocks in Northern Japan 