TY - JOUR
T1 - Sediment dispersal patterns in a deep marine back-arc basin
T2 - Evidence from heavy mineral provenance studies
AU - Browne, J. R.
AU - Pirrie, D.
PY - 1995
Y1 - 1995
N2 - Heavy mineral provenance studies can aid reservoir description in deep marine depositional systems by providing a clearer understanding of the lateral extent of discrete sediment bodies. In this study the lower Gustav Group (Lagrelius Point, Kotick Point and Whisky Bay formations) of James Ross Island, Antarctica, which was deposited in a deep marine slope-apron-submarine fan complex has been investigated. The Kotick Point and Whisky Bay formations crop out in two separate areas on the west coast of James Ross Island. The provenance of the group has been studied by both standard sandstone petrography and electron microprobe analysis of the heavy minerals' garnet, pyroxene and Fe-Ti oxides. The sandstones are lithic to arkosic arenites derived from the adjacent Antarctic Peninsula magmatic arc. Although the general source area can be recognized, individual stratigraphical or depositional units cannot be distinguished on the basis of sandstone petrography. However, electron microprobe analyses of the detrital heavy minerals allows a more detailed discrimination of sediment provenance. In particular, analyses of the detrital Fe-Ti oxide minerals show that in the Whisky Bay Formation, the southern outcrop area, contains ilmenite, whilst the northern outcrop area contains titanomagnetite. In conjunction with the available biostratigraphical and palaeocurrent evidence, this can be interpreted in two ways. Firstly, if the two outcrop areas are direct age equivalents then they were derived from separate point sources, and deposited as discrete sediment lobes. Alternatively, if they are not directly time-equivalent, the depositional system may have switched laterally with time, with sediment derived from source rocks of varying composition. Either interpretation has implications for the understanding of the deep marine depositional system. Detrital opaque minerals are commonly source specific and should not be ignored during provenance studies.
AB - Heavy mineral provenance studies can aid reservoir description in deep marine depositional systems by providing a clearer understanding of the lateral extent of discrete sediment bodies. In this study the lower Gustav Group (Lagrelius Point, Kotick Point and Whisky Bay formations) of James Ross Island, Antarctica, which was deposited in a deep marine slope-apron-submarine fan complex has been investigated. The Kotick Point and Whisky Bay formations crop out in two separate areas on the west coast of James Ross Island. The provenance of the group has been studied by both standard sandstone petrography and electron microprobe analysis of the heavy minerals' garnet, pyroxene and Fe-Ti oxides. The sandstones are lithic to arkosic arenites derived from the adjacent Antarctic Peninsula magmatic arc. Although the general source area can be recognized, individual stratigraphical or depositional units cannot be distinguished on the basis of sandstone petrography. However, electron microprobe analyses of the detrital heavy minerals allows a more detailed discrimination of sediment provenance. In particular, analyses of the detrital Fe-Ti oxide minerals show that in the Whisky Bay Formation, the southern outcrop area, contains ilmenite, whilst the northern outcrop area contains titanomagnetite. In conjunction with the available biostratigraphical and palaeocurrent evidence, this can be interpreted in two ways. Firstly, if the two outcrop areas are direct age equivalents then they were derived from separate point sources, and deposited as discrete sediment lobes. Alternatively, if they are not directly time-equivalent, the depositional system may have switched laterally with time, with sediment derived from source rocks of varying composition. Either interpretation has implications for the understanding of the deep marine depositional system. Detrital opaque minerals are commonly source specific and should not be ignored during provenance studies.
U2 - 10.1144/GSL.SP.1995.094.01.11
DO - 10.1144/GSL.SP.1995.094.01.11
M3 - Article
AN - SCOPUS:0042396181
SN - 0305-8719
VL - 94
SP - 137
EP - 154
JO - Geological Society Special Publication
JF - Geological Society Special Publication
ER -
