A Clay Mineral Provenance Study of the Northern Pandora Trough Continental Margin, Gulf of Papua

Ashley Howell
Louisiana State University, Department of Geology and Geophysics Baton Rouge, LA, USA
[email protected]

X-ray diffraction mineralogy of western-, central-, and eastern-derived fluvial sediments within the Gulf of Papua exhibits distinct and mixed clay mineral assemblages. These mineral assemblages allow for a better understanding of how a thick muddy continental margin shelf-edge depocenter in the eastern Gulf of Papua of latest Pleistocene/early Holocene age formed, as well as connections between terrestrial sediment delivery and evolution of deep-sea deposits in this region.

Modern clay mineralogy reveals a high to low gradation of illite/smectite values from the western to eastern Gulf of Papua, which is applied to the recent past for provenance indications within this study. The shelf-edge depocenter, at the MV-41 core location, analyzed in this study formed during the Bølling-Allerød/Younger Dryas when the shoreline was located < 10 km landward of the modern shelf-edge and mass accumulation rates were high, thus allowing for minimal illite/smectite-dominated sediment input from the western and central GoP. However, modern X-ray diffraction data show a higher kaolinite/chlorite input, indicative of a more local, volcanic source, potentially within the Lakekamu River catchment. This mineral assemblage is distinct from the higher illite/smectite and lower kaolinite/chlorite signatures within the upper/middle slope cores, MV-46 and MV-49, and is consistent with modern central Gulf of Papua surficial clay mineralogy being Purari River-derived. This analysis of clay-rich mud provenances, in conjunction with other analyses, provides an improvement of understanding modern mudflow, and potentially the paleogeographical extent of clay-rich muds in unconventional shale plays.

AAPG Search and Discovery Article #90183©2013 AAPG Foundation 2013 Grants-in-Aid Projects