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The International Ocean Discovery Program (IODP) Expedition 356 Site U1461 cored a Miocene to Holocene sedimentary sequence in the upper bathyal carbonate offshore northwestern Australia (NWA). The siliciclastic component of these strata is primarily derived from the Australian continent. Radiocarbon dating on macrofossils and planktonic foraminifera shows that the upper 14 m section at Site U1461 preserves Holocene sediments, recording regional climate variability. K/Ca ratios determined by X-ray fluorescence elemental analyses and %K determined by shipboard natural gamma ray analysis are interpreted as indicators of riverine run-off from the Australian continent. We document the consequences of the variability of the Australian Summer Monsoon (ASM) on the continental shelf of NWA. We report an increase in terrigenous input due to a riverine run-off after 11.5 ka, which reaches a maximum at similar to 8.5 ka. This maximum is the result of the enhanced ASM-derived precipitation in response to the southern migration of the Intertropical Convergence Zone (ITCZ). A decrease in riverine run-off due to a weakening of precipitation in the NWA region after 8.5 ka was caused by the northern migration of the ITCZ. We conclude that the ITCZ reached its southernmost position at 8.5 ka and enhanced precipitation in the NWA region. This Holocene record shows that even during interglacial periods, monsoonal variability was primarily controlled by the position of the ITCZ.

The International Ocean Discovery Program (IODP) Expedition 356 Site U1461 cored a Miocene to Holocene sedimentary sequence in the upper bathyal carbonate offshore northwestern Australia (NWA). The siliciclastic component of these strata is primarily derived from the Australian continent. Radiocarbon dating on macrofossils and planktonic foraminifera shows that the upper 14 m section at Site U1461 preserves Holocene sediments, recording regional climate variability. K/Ca ratios determined by X-ray fluorescence elemental analyses and %K determined by shipboard natural gamma ray analysis are interpreted as indicators of riverine run-off from the Australian continent. We document the consequences of the variability of the Australian Summer Monsoon (ASM) on the continental shelf of NWA. We report an increase in terrigenous input due to a riverine run-off after 11.5 ka, which reaches a maximum at similar to 8.5 ka. This maximum is the result of the enhanced ASM-derived precipitation in response to the southern migration of the Intertropical Convergence Zone (ITCZ). A decrease in riverine run-off due to a weakening of precipitation in the NWA region after 8.5 ka was caused by the northern migration of the ITCZ. We conclude that the ITCZ reached its southernmost position at 8.5 ka and enhanced precipitation in the NWA region. This Holocene record shows that even during interglacial periods, monsoonal variability was primarily controlled by the position of the ITCZ.

The International Ocean Discovery Program (IODP) Expedition 356 Site U1461 cored a Miocene to Holocene sedimentary sequence in the upper bathyal carbonate offshore northwestern Australia (NWA). The siliciclastic component of these strata is primarily derived from the Australian continent. Radiocarbon dating on macrofossils and planktonic foraminifera shows that the upper 14 m section at Site U1461 preserves Holocene sediments, recording regional climate variability. K/Ca ratios determined by X-ray fluorescence elemental analyses and %K determined by shipboard natural gamma ray analysis are interpreted as indicators of riverine run-off from the Australian continent. We document the consequences of the variability of the Australian Summer Monsoon (ASM) on the continental shelf of NWA. We report an increase in terrigenous input due to a riverine run-off after 11.5 ka, which reaches a maximum at similar to 8.5 ka. This maximum is the result of the enhanced ASM-derived precipitation in response to the southern migration of the Intertropical Convergence Zone (ITCZ). A decrease in riverine run-off due to a weakening of precipitation in the NWA region after 8.5 ka was caused by the northern migration of the ITCZ. We conclude that the ITCZ reached its southernmost position at 8.5 ka and enhanced precipitation in the NWA region. This Holocene record shows that even during interglacial periods, monsoonal variability was primarily controlled by the position of the ITCZ.

The coccolithophore genus Scyphosphaera exhibits two distinct types of coccoliths: muroliths that are spherical in shape and lopadoliths that are vase or cup-shaped. Extant species show highly polymorphic lopadoliths that can vary in size and shape on one single cell. In the past, especially in the Pliocene, the genus Scyphosphaera was morphologically highly diverse, which makes it a great group for studying evolutionary and ecological processes. The main aim of this study was to quantitatively analyze the morphological variation of lopadoliths found in two drill sites, Site U1462 and Site U1463, on the northwestern continental margin of Australia as part of the International Ocean Discovery Program (IODP). These sites were drilled during IODP Expedition 356 that documented sedimentary sequences of the last 5 million years, during which the Earth experienced major changes in climate moving from warmer to ice age conditions (Gallagher et al. 2017). The second aim was to recognize whether the morhological variation represents phenotypic variation within one or few (morpho) species of Scyphosphaera or if those differences in morphology are indicative of distinct species. A third aim was to compare regional and lateral diversity and abundance of the Scyphosphaera genus in the samples from both sites for understanding regional changes in the (post-depositional) environment. Three different groups were determined, depending on the shape and based on 1, 4 or 5 measured parameters of the lopadoliths. In group I, five parameters were defined, in group II, four parameters were defined and in group III only one parameter was defined. In order to determine the absolute abundance of Scyphosphaera species within the sediment, the drop technique (Bordiga, Bartol & Henderiks 2015) was used for preparation of microscope slides. A linear age model was constructed using three marker taxa. Altogether 440 specimens were collected and included in the biometric analysis. The biometric, Släktet Scyphosphaera är en grupp coccolitoforider som är encelliga planktiska alger som spelar en viktig roll i globala biokemiska cykler. Levande coccolitoforider i släktet Scyphosphaera utsöndrar två distinkta typer av kalkartade plattor (coccoliter). Den första typen kallas muroliter och är cirkulära och platta, medan den andra typen kallas lopadoliter och är vasformade. Bland fossila coccoliter är lopadoliter de enda som kan tillräknas släktet Scyphosphaera, eftersom muroliter tillhör ett annat släkte som kallas Pontosphaera. Studier som gjorts på levande arter visade att lopadoliter kan variera i storlek och form på en och samma cell. Fossila arter grundas på morfologiska skillnader hos lopadoliterna. Därför är det inte uppenbart huruvida fossila lopadoliter med olika morfologier tillhör olika arter eller kan tillskrivas en art som producerar olika typer av lopadoliter. Den här studien har fokuserat på att lösa detta problem genom att utföra en biometrisk analys av lopadoliter. Huvudområdet i studien var två borrplatser, Site U1462 och U1463, på Nordvästra Australiens kontinentalsockel som borrades av International Ocean Drilling Program (IODP) Expedition 356. Mångfäld och artrikedom av släktet Scyphosphaera noterades och jämfördes mellan de två borrplatserna. Lopadoliter delades in i 11 morfotyper beroende på morfologiska skillnader, och dessa morfotyper delades i sin tur in i tre grupper. Grupper identifierades genom ett antal parametrar som användes för den biometriska analysen. Grupp I definierades av fem parametrar, grupp II av fyra parametrar, och grupp III av en parameter. Studien har visat att i grupp I är morfotyper 1 och 6 olika i storlek och form hos lopadoliter och tillhör därför olika art. Morfotyp 7 i grupp II är den mest distinkta morfotypen och kan därför tolkas som en egen art i jämförelse med andra morfotyper som ingick i gruppen. Morfotyp 3 i grupp III har tolkats som ett tvärsnitt av lopadoliter som fylldes med mineral under diagenetiska fö

This study explores the application of soil micromorphological and automated scanning electron microscopy mineralogical analysis to characterise lithological boundaries and site formation history from an archaeological cave site on Barrow Island, northwestern Australia. The high-resolution characterisation is used to document the changing depositional context within Boodie Cave from the earliest period of occupation around 50 ky BP through to when transgressing seas isolated the island around 7 ky BP. Comparisons are made between excavations at the front of the cave — where stratigraphic integrity is high and a thicker, more comprehensive early Holocene sequence is preserved, with excavations inside the cave — where stratigraphic integrity is lower but an older Pleistocene record is preserved. The combination of these depositional scenarios provides a complete stratigraphic sequence for Boodie Cave, with depositional contacts defined at macro-, meso- and microscale levels. These contacts include erosive surfaces and trampled (ground) surfaces, such as the upper interface of SU5 and SU4. Based on the mineralogical and textural variations (microfacies) preserved within each unit, the vertical mixing zone is estimated to be between 1 and 5 cm. This reworking has not affected the general sequence of sedimentological (including grain size and mineralogy) and macro-cultural changes, which record an increasingly marine-dominated assemblage as the coastline encroaches. The integration of microscopic observations with anthracological, archaeomalacological, zooarchaeological and lithic analyses provides a more dynamic and comprehensive dialogue for interpreting the formation history of Boodie Cave and likely other early occupation sites from northern Australia

A new genus and species of bathyal bythitid fish (Teleostei: Ophidiiformes) is described based on a single specimen caught at a depth of 392 m in the Timor Sea off the coast of northwestern Australia. Timorichthys disjunctus gen. nov., sp. nov. differs from all other bythitid genera by the position of the anus midway between the tip of the snout and origin of the anal fin. The joined vertical fins and the type of intromittant organ furthermore place the new genus in the subfamily Bythitinae.

A new genus and species of bathyal bythitid fish (Teleostei: Ophidiiformes) is described based on a single specimen caught at a depth of 392 m in the Timor Sea off the coast of northwestern Australia. Timorichthys disjunctus gen. nov., sp. nov. differs from all other bythitid genera by the position of the anus midway between the tip of the snout and origin of the anal fin. The joined vertical fins and the type of intromittant organ furthermore place the new genus in the subfamily Bythitinae.

A new genus and species of bathyal bythitid fish (Teleostei: Ophidiiformes) is described based on a single specimen caught at a depth of 392 m in the Timor Sea off the coast of northwestern Australia. Timorichthys disjunctus gen. nov., sp. nov. differs from all other bythitid genera by the position of the anus midway between the tip of the snout and origin of the anal fin. The joined vertical fins and the type of intromittant organ furthermore place the new genus in the subfamily Bythitinae.