TY - CONF
T1 - Structural framework of the Maremane Dome: Selective iron ore preservation
AU - Basson, Ian
AU - Wooldridge, Adam
AU - King, J.A.
AU - Doyle, Gavin
AU - Nel, Deon
AU - McGregor, Stuart
PY - 2016/8
Y1 - 2016/8
N2 - A compilation of regional airborne magnetic, electromagnetic, radiometric and remote sensing data allows for a revised structural interpretation of the Maremane Dome area, encompassing Sishen and Kolomela Mines. Dominant major structures comprise strike-extensive, N-S trending, steep, predominantly W-dipping (listric-at-depth), normal and inverted normal faults, notably prevalent within the western half of the Maremane Dome. Normal faulting probably initiated prior to the deposition of the Ghaap Group or deposition of Koegas Subgroup units at c. ~2.43-2.35 Ga, although these structures underwent numerous phases of reactivation. Fault drag occurred mainly during the superimposed Kheis Orogeny, wherein N-S trending normal faults were inverted by a second phase of eastward tectonic vergence at c. 1.4 to 1.25 Ga. This resulted in mine-scale, N-S trending synclines to the west of these faults, typified by the Sloep Fault and “Sloep Syncline” at Sishen Mine. NE/ENE- and SE/ESE-trending, subvertical faults cross-cut and offset N-S trending faults. Typical spacing of these faults, recorded at Sishen Mine, is 100-500m or “prospect- or sub-pit-scale”. ENE- and NE-trending faults may have originated with the development of the Ventersdorp Rift Basin at c. 2.6 Ga to 2.5 Ga. Reactivated between c. 1.73 Ga and 1.4 Ga, ESE- and ENE-trending faults also underwent a degree of transpression, possibly during c. 1.4-1.25 Ga inversion. Thick diabase dykes exploited major, N-S trending structures, which are at least similar in offset and extent to the Sloep Fault. Such dykes are distributed across the entire area of interest, although they are locally clustered in a wedge-shaped zone immediately to the west of Sishen Mine.
AB - A compilation of regional airborne magnetic, electromagnetic, radiometric and remote sensing data allows for a revised structural interpretation of the Maremane Dome area, encompassing Sishen and Kolomela Mines. Dominant major structures comprise strike-extensive, N-S trending, steep, predominantly W-dipping (listric-at-depth), normal and inverted normal faults, notably prevalent within the western half of the Maremane Dome. Normal faulting probably initiated prior to the deposition of the Ghaap Group or deposition of Koegas Subgroup units at c. ~2.43-2.35 Ga, although these structures underwent numerous phases of reactivation. Fault drag occurred mainly during the superimposed Kheis Orogeny, wherein N-S trending normal faults were inverted by a second phase of eastward tectonic vergence at c. 1.4 to 1.25 Ga. This resulted in mine-scale, N-S trending synclines to the west of these faults, typified by the Sloep Fault and “Sloep Syncline” at Sishen Mine. NE/ENE- and SE/ESE-trending, subvertical faults cross-cut and offset N-S trending faults. Typical spacing of these faults, recorded at Sishen Mine, is 100-500m or “prospect- or sub-pit-scale”. ENE- and NE-trending faults may have originated with the development of the Ventersdorp Rift Basin at c. 2.6 Ga to 2.5 Ga. Reactivated between c. 1.73 Ga and 1.4 Ga, ESE- and ENE-trending faults also underwent a degree of transpression, possibly during c. 1.4-1.25 Ga inversion. Thick diabase dykes exploited major, N-S trending structures, which are at least similar in offset and extent to the Sloep Fault. Such dykes are distributed across the entire area of interest, although they are locally clustered in a wedge-shaped zone immediately to the west of Sishen Mine.
M3 - Abstract
ER -