The GRAVITY+ Project: Towards All-sky, Faint-Science, High-Contrast Near-Infrared Interferometry at the VLTI

The GRAVITY instrument has been revolutionary for near-infrared interferometry by pushing sensitivity and precision to previously unknown limits. With the upgrade of GRAVITY and the Very Large Telescope Interferometer (VLTI) in GRAVITY+, these limits will be pushed even further, with vastly improved sky coverage, as well as faint-science and high-contrast capabilities. This upgrade includes the implementation of wide-field off-axis fringe-tracking, new adaptive optics systems on all Unit Telescopes, and laser guide stars in an upgraded facility. GRAVITY+ will open up the sky to the measurement of black hole masses across cosmic time in hundreds of active galactic nuclei, use the faint stars in the Galactic centre to probe General Relativity, and enable the characterisation of dozens of young exoplanets to study their formation, bearing the promise of another scientific revolution to come at the VLTI.Comment: Published in the ESO Messenge

Vertikalverteilung lebender benthischer Foraminiferen im Südchinesischen Meer

The vertical distribution of living deep-sea benthic foraminifera is investigated in three cores from the South China Sea. Arenaceous foraminifera dominate the faunal composition. The high species diversity, which decreases with increasing water-depth, is characteristic for oligotrophic regions. In all three cores the numbers of stained foraminifera decrease rapidly in 2-4 cm depth. A relation with changing oxic conditions is not obvious, as the upper redox-horizon of the deepest core is located in 6-7 cm depth. A strong abundance-peak also lies underneath this horizon. The vertical distribution of 6 calcareous and 9 arenaceous groups are studied in detail. Species of the genus Reophax are most significant due to high abundance in surface and deeper sediments. Nouria harrisii is described from dysoxic sediments for the first time. Finally, a correlation with Rathburn & Corliss' (1994) vertical distribution concept is discussed in relation to various morphotype concepts

(Table T1) Fossil, magnetic reversal, and additional datums of ODP Leg 189 sites

The aim of this study is to assess the viability of age models based on shipboard and postcruise bio- and magnetostratigraphic datums, as of August 2002, using independently derived control points. The control points are based on matching between-site trends in stable isotope records, carbonate content, and weight percent sand. Site 1170 on the western South Tasman Rise has a good record of magnetic reversals, which suggests a hiatus prior to ~30 Ma (early Oligocene) relating to the Marshall Paraconformity, followed by strongly reduced sedimentation in the late Oligocene. Preservation of the Mi-1 event at this site is evidence for continued sedimentation across the Oligocene/Miocene boundary. Correlation of the Mi-1a event to the record at Site 1090 on the Agulhas Ridge confirms the usefulness of the magnetostratigraphic record at this site. However, the timing of the Mi-1 event at Site 1170 appears different from that at Site 1090, but is constrained by four magnetic reversals. At Site 1171 additional control points are consistent with biostratigraphic datums. Site 1172 is marked by the lowest sedimentation rates of all sites. Additional control points before 22 Ma are more consistent with the biostratigraphy than with the magnetostratigraphy. At Site 1168 we suggest that the magnetic reversal record MR1 provides the best match with the biostratigraphy and additional control points, as well as changes in the biogenic and lithogenic composition of the sedimentary record. The late Eocene/early Oligocene Marshall Paraconformity (base = ~33 Ma at the type location) is evident at Sites 1170-1172, and low sedimentation rates occur at the two eastern sites (1171 and 1172) in the early Oligocene. A change in sedimentation just after the early-late Oligocene transition appears to reduce rates at Site 1170 and strongly affect the biogenic composition of sediments at Site 1168, which is less exposed to the flow of the Antarctic Circumpolar Current. The Oligocene-Miocene transition finally is marked by reduced sedimentation at Sites 1170-1172, but a relatively stronger decrease is noticeable at Site 1168. Above this boundary sedimentation rates are identical at Sites 1168 and 1170 above 21.5 Ma and at Sites 1171 and 1172 above 17 Ma

Stable carbon and oxygen isotope ratios of foraminifera from the latest Miocene to earliest Pliocene of Ceare Rise, western tropical Atlantic

We present a detailed study of menardellid speciation, abundance and coiling changes between 6.34 and 5.1 Ma (latest Miocene and earliest Pliocene). Menardellids are widely distributed in tropical to subtropical waters from Miocene to modern time, revealing a stable isotopic signature characteristic for the top of the thermocline and shallower rather than deeper habitat depth. Menardellid response to its environment reveals a tripartite pattern. The first interval from ~6.34 to 5.75 Ma is marked by a dominance of Menardella limbata, frequent changes in coiling direction, and variable abundance with strongest reductions during intervals of dextral dominance. The onset of an interval of cooling and ice build-up at 5.82 Ma coincides with a weakening of the mixed layer leading to nearly 70 kyr of strongly reduced menardellid abundance. At 5.75 Ma, Menardella multicamerata replaces M. limbata as the prevailing menardellid species, at the same time as the overall abundance of menardellids stabilises. Initial stabilisation of sinistral coiling until the end of the cold interval at ~5.49 Ma suggests the development of a temperature preference in sinistral (cold) and dextral (warm) M. multicamerata. A strong increase in menardellid delta13C values relative to the thermocline gradient (difference between the delta18O records of surface-dwelling Globigerinoides trilobus and Menardella spp.) following 5.77 Ma suggests a move to shallower habitat depths of both M. multicamerata morphotypes. Initiated by mixed layer destabilisation, both the development of a temperature preference and the move to shallower habitat depth in M. multicamerata appear to identify its adjustment to a new niche driving the replacement of M. limbata as the dominant menardellid species

Biomagnetostratigraphy of ODP Leg 189 sites

Late Cretaceous (Maastrichtian)-Quaternary summary biostratigraphies are presented for Ocean Drilling Program (ODP) Leg 189 Sites 1168 (West Tasmanian Margin), 1170 and 1171 (South Tasman Rise), and 1172 (East Tasman Plateau). The age models are calibrated to magnetostratigraphy and integrate both calcareous (planktonic foraminifers and nannofossils) and siliceous (diatoms and radiolarians) microfossil groups with organic walled microfossils (organic walled dinoflagellate cysts, or dinocysts). We also incorporate benthic oxygen isotope stratigraphies into the upper Quaternary parts of the age models for further control. The purpose of this paper is to provide a summary age-depth model for all deep-penetrating sites of Leg 189 incorporating updated shipboard biostratigraphic data with new information obtained during the 3 yr since the cruise. In this respect we provide a report of work to November 2003, not a final synthesis of the biomagnetostratigraphy of Leg 189, yet we present the most complete integrated age model for these sites at this time. Detailed information of the stratigraphy of individual fossil groups, paleomagnetism, and isotope data are presented elsewhere. Ongoing efforts aim toward further integration of age information for Leg 189 sites and will include an attempt to correlate zonation schemes for all the major microfossil groups and detailed correlation between all sites