Table T5. Structural identifier checklist used for spreadsheet comments associated with each structural identifier.
| Structural identifier | Observations included |
|---|---|
| Subhorizontal microcracks (Shm) | Drilling-induced fractures |
| Joints (J) | Joint density |
| Orientation | |
| Plume structures on joint surface | |
| Veins (V) | Hydrothermal (Vh), fault with fibrous mineral (Vf), with cataclasis (Vc) |
| Orientation of veins and vein-array boundaries | |
| Width and length | |
| Magnitude and nature of offset: n = normal, r = reverse, ss = strike slip | |
| Density of vein network (N/10 cm) | |
| Array characteristics | |
| Sense of shear: d = dextral, s = sinistral | |
| Angle between new vein segments and array boundary (measure of array dilatation) | |
| Internal structure of fibers | |
| Crack-seal structures and number of vein-opening events | |
| Wallrock alteration and shape—sharp or diffuse boundaries | |
| Vein terminations (splayed or tapered) | |
| Vein mineralogy | |
| Magmatic vein (Vm) | |
| Alteration vein (Va) | |
| Faults (F) | Fault-zone thickness, orientation, and density |
| Movement sense: r = reverse, n = normal, d = dextral, s = sinistral | |
| Movement offset (displacement, millimeters) | |
| Intensity of cataclastic fabric (Cf) | |
| Cataclastic foliation (Scc) | |
| Matrix material (gouge or secondary minerals) | |
| Overprinting of preexisting fabric | |
| Semibrittle | |
| Breccias (B) | Hydrothermal (Bh), Magmatic (Bm),Cataclastic (Bc) |
| Clast size and shape, matrix composition, relative proportions | |
| Serpentinization foliation (S) | Strength of foliation |
| Orientation of foliation in core reference frame | |
| Brittle-plastic fabrics (Bp) | Intensity of fabric |
| Orientation of foliation | |
| Intensity of fabric | |
| Crystal-plastic fabrics (CPf) | Intensity of fabric in retrograde assemblage |
| Orientation of foliation (Sp) and lineation (Lp) | |
| L-, LS-, and S-tectonite | |
| Shear sense indicators: block-rotated porphyroclasts, asymmetric augen, SC fabrics, discrete shear bands, mica-fish, and tension gash arrays: r = reverse, n = normal, d = dextral, s = sinistral | |
| Mineralogical segregation or banding | |
| Intensity and orientation of foliations (Sm) and lineations (Lm) | |
| Magmatic fabrics (Mf) | Minerals that define the shape and/or crystallographic preferred orientations |
| Angle between crystallographic and shape fabrics | |
| Orientation of subfabrics | |
| Compositional layering (Cl) | Type of layering (e.g., igneous cumulate, alteration, etc.); orientation, thickness, and density of layers |
| Grain size layering (Gs), compositional "modal" layering (Cl) | |
| Orientation and density | |
| Igneous contacts (Ic) | Concordant or discordant |
| Crosscutting relationships | Intrusive relationships, relative chronology of the different fabrics |
| Angle between compositional layering and magmatic or crystal-plastic fabric |
Notes: This checklist notes structural characteristics that were searched for in macroscopic core samples. These characteristics supplement the information required by the spreadsheet and were noted in the comments section of the spreadsheet. The abbreviations for these features were used to document crosscutting relationships on the structure section of the visual core descriptions.
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