The Miocene Wonosari Formation, Java, Indonesia Volcaniclastic influences on carbonate platform development

In 2 volsAvailable from British Library Document Supply Centre-DSC:DXN043800 / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo

Siliciclastic and volcaniclastic influences on equatorial carbonates: insights from the Neogene of Indonesia

In active tectonic areas of humid equatorial regions, nearshore shallow-water environments are commonly sites of near-continuous siliciclastic influx and/or punctuated volcaniclastic input. Despite significant clastic influence, Neogene carbonates developed in SE Asia adjacent to major deltas or volcanic arcs, and are comparable with modern mixed carbonate–clastic deposits in the region. Research into delta-front patch reefs from Borneo and fore-arc carbonate platform development from Java is described and used to evaluate the effects of siliciclastic and volcaniclastic influx on regional carbonate sedimentation, local changes in carbonate-producing biota and sequence development. Regional carbonate development in areas of high siliciclastic or volcaniclastic input was influenced by the presence of antecedent highs, changes in the amounts or rates of clastic input, delta lobe switching or variations in volcanic activity, energy regimes and relative sea-level change. A variety of carbonate-producing organisms, including larger benthic foraminifera, some corals, coralline algae, echinoderms and molluscs could tolerate near-continuous siliciclastic or volcaniclastic influx approximately equal to their own production rates. These organisms adopted various 'strategies' for coping with clastic input, including a degree of mobility, morphologies adapted to unstable substrate inhabitation or shedding sediment, and shapes adapted to low light levels. Local carbonate production was also affected by energy regime, clastic grain sizes and associated nutrient input. Clastic input influenced the inhabitable depth range for photoautotrophs, the zonation of light-dependent assemblages and the morphology and sequence development of mixed carbonate–clastic successions. This study provides data on the dynamic interactions between carbonate and non-carbonate clastic sediments and, when combined with information from comparable modern environments, allows a better understanding of the effects of siliciclastic and volcaniclastic influx on carbonate production

Biotically constrained palaeoenvironmental conditions of a mid-Holocene intertidal lagoon on the southern shore of the Arabian Gulf: evidence associated with a whale skeleton at Musaffah, Abu Dhabi, UAE

Whale remains (a left and right mandible, scapula, humerus and fragmentary radius and ulna as well as parts of the cranium and rostrum) belonging to a probable humpback whale (Megaptera cf. novaeangliae) were found in the well-described sabkha sequence exposed in the Musaffah Industrial Channel, Abu Dhabi, United Arab Emirates. More precisely, the whale remains were found in a series of sediments representing a range of lagoonal facies. The sediments surrounding the whale bones were age-dated at approximately 5200 14C yrs BP and are herefore interpreted to correspond to the previously documented late Flandrian sea-level peak, receding a fall in sea-level which culminated in the supratidal sabkha overprint of the carbonates. associated with the whale remains is an assemblage of molluscs, foraminifera and ostracods. together with the inferred presence of sea grass and algae, these facies are interpreted to indicate a very shallow subtidal to intertidal lagoonal environment. Cirripede remains found associated with the skeleton were identified as those of the whale barnacle Coronula diadema and hence had their origins with the whale. Significantly, the low species diversity of microfossils suggests that higher salinities existed in the mid-Holocene lagoon than are present in modern counterparts. This is here inferred to be related to the onset of continental aridity in Arabia during the mid-Holocene