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Table 8 Bulk lithostatic and hydrostatic stress applied to each formation

From: Matrix permeability of reservoir rocks, Ngatamariki geothermal field, Taupo Volcanic Zone, New Zealand

Bulk stress applied by lithostatic pressure and hydrostatic pressure (MPa)
Formation NM2 NM3 NM4 NM8a NM11
Litho. Hydro. Litho. Hydro. Litho. Hydro. Litho. Hydro. Litho. Hydro.
Oruanui 1.6 1.1 1.6 1.1 0.64 0.44 0.74 0.51 0.78 0.54
Huka falls Fm 1.6 1.5 1.6 1.5 1.5 1.5 1.7 1.7 1.8 1.7
Rhyolite 2.9 1.6 5.4 3.0 4.3 2.4 1.3 0.74 2.9 1.6
Waiora Fm 0.73 0.34    4.5 2.1 1.8 0.83 3.9 0.18
Whakamaru group ignimbrite 4.0 2.0 2.1 1.0 3.6 1.8 6.5 3.2 1.1 5.6
Tahorakuri sedimentary succession 7.0 3.6 6.2 3.2 2.3 1.2 6.9 3.5 4.8 2.5
Tahorakuri quartz-rhyolite 1.6 6.9 4.1 1.8 4.1 1.8     
Tahorakuri pyroclastic succession 25 11 17 7.3 23 9.6 38 16 28 12
Tahorakuri volcaniclastic andesite breccia 1.3 0.54      2.5 1.0   
Tahorakuri volcaniclastic andesite breccia 3.3 1.3         
Porphyritic microdiorite–diorite        3.9 1.4   
Quartz-bearing diorite        5.8 2.1   
Tonalite        11 4.5