Developing community-based scientific priorities and new drilling proposals in the southern Indian and southwestern Pacific oceans

Abstract: An International Ocean Discovery Program (IODP) workshop was held at Sydney University, Australia, from 13 to 16 June 2017 and was attended by 97 scientists from 12 countries. The aim of the workshop was to investigate future drilling opportunities in the eastern Indian Ocean, southwestern Pacific Ocean, and the Indian and Pacific sectors of the … Read more…

Pantasma: Evidence for a Pleistocene circa 14 km diameter impact crater in Nicaragua

Abstract–The circa 14 km diameter Pantasma circular structure in Oligocene volcanic rocks in Nicaragua is here studied for the first time to understand its origin. Geomorphology, field mapping, and petrographic and geochemical investigations all are consistent with an impact origin for the Pantasma structure. Observations supporting an impact origin include outward-dipping volcanic flows, the presence … Read more…

Rift and plate boundary evolution across two super-continent cycles

Abstract The extent of continental rifts and subduction zones through deep geological time provides insights into the mechanisms behind supercontinent cycles and the long term evolution of the mantle. However, previous compilations have stopped short of mapping the locations of rifts and subduction zones continuously since the Neoproterozoic and within a self-consistent plate kinematic framework. … Read more…

Australian-Antarctic breakup and seafloor spreading: Balancing geological and geophysical constraints

Abstract  The motion of diverging tectonic plates is typically constrained by geophysical data from preserved ocean crust. However, constraining plate motions during continental rifting and the breakup process relies on balancing evidence from a diverse range of geological and geophysical observations, often subject to differing interpretations. Reconstructing the evolution of rifting and breakup between Australia and Antarctica epitomizes the challenges involved in … Read more…

Geodynamic reconstruction of an accreted Cretaceous back-arc basin in the Northern Andes

Abstract A complex history of subduction, back-arc basin formation, terrane accretion and transpressional shearing characterizes the evolution of the Caribbean and northern South American margin since Jurassic times. Quantitative plate tectonic reconstructions of the area do not include Jurassic-Cretaceous back-arc terranes of which there are both geological and geophysical observations. We developed a revised plate … Read more…

Oblique rifting: the rule, not the exception

Abstract: Movements of tectonic plates often induce oblique deformation at divergent plate boundaries. This is in striking contrast with traditional conceptual models of rifting and rifted margin formation, which often assume 2-D deformation where the rift velocity is oriented perpendicular to the plate boundary. Here we quantify the validity of this assumption by analysing the kinematics … Read more…

The influence of carbonate platform interactions with subduction zone volcanism on palaeo-atmospheric CO2 since the Devonian

Abstract: The CO2 liberated along subduction zones through intrusive/extrusive magmatic activity and the resulting active and diffuse outgassing influences global atmospheric CO2. However, when melts derived from subduction zones intersect buried carbonate platforms, decarbonation reactions may cause the contribution to atmospheric CO2 to be far greater than segments of the active margin that lacks buried carbon-rich rocks and … Read more…

Exploring coral reef responses to millennial-scale climatic forcings: insights from the 1-D numerical tool pyReef-Core v1.0

Abstract: Assemblages of corals characterise specific reef biozones and the environmental conditions that change spatially across a reef and with depth. Drill cores through fossil reefs record the time and depth distribution of assemblages, which captures a partial history of the vertical growth response of reefs to changing palaeoenvironmental conditions. The effects of environmental factors on … Read more…

Global kinematics of tectonic plates and subduction zones since the late Paleozoic Period

Abstract: Detailed global plate motion models that provide a continuous description of plate boundaries through time are an effective tool for exploring processes both at and below the Earth’s surface. A new generation of numerical models of mantle dynamics pre- and post-Pangea timeframes requires global kinematic descriptions with full plate reconstructions extending into the Paleozoic … Read more…

The Interplay Between the Eruption and Weathering of Large Igneous Provinces and the Deep-Time Carbon Cycle

Abstract: Although many sources of atmospheric CO2 have been estimated, the major sinks are poorly understood in a deep-time context. Here we combine plate reconstructions, the eruption ages and outlines of Large Igneous Provinces (LIPs), and the atmospheric CO2 proxy record to investigate how their eruptions and weathering within the equatorial humid zone impacted global … Read more…

PyBacktrack 1.0: a tool for reconstructing paleobathymetry on oceanic and continental crust

The pyBacktrack software package allows the backtracking of the paleo-water depth of ocean drill sites, providing a framework for reconstructing the accumulation history of sediment components through time. The software incorporates the effects of decompaction of common marine lithologies and allows backtracking of sites on both oceanic and continental crust.  Backtracking on ocean crust is based on … Read more…

Regional volcanism of northern Zealandia: post-Gondwana break-up magmatism on an extended, submerged continent

Abstract Abstract: Volcanism of Late Cretaceous–Miocene age is more widespread across the Zealandia continent than previously recognized. New age and geochemical information from widely spaced northern Zealandia seafloor samples can be related to three volcanotectonic regimes: (1) age-progressive, hotspot-style, low-K, alkali-basalt-dominated volcanism in the Lord Howe Seamount Chain. The northern end of the chain (c. … Read more…

Controls on the global distribution of contourite drifts: Insights from an eddy-resolving ocean model

Abstract Contourite drifts are anomalously high sediment accumulations that form due to reworking by bottom currents. Due to the lack of a comprehensive contourite database, the link between vigorous bottom water activity and drift occurrence has yet to be demonstrated on a global scale. Using an eddy-resolving ocean model and a new georeferenced database of 267 contourites, we show that the … Read more…

pyBadlands: A framework to simulate sediment transport, landscape dynamics and basin stratigraphic evolution through space and time

Abstract Understanding Earth surface responses in terms of sediment dynamics to climatic variability and tectonics forcing is hindered by limited ability of current models to simulate long-term evolution of sediment transfer and associated morphological changes. This paper presents pyBadlands, an open-source python-based framework which computes over geological time (1) sediment transport from landmasses to coasts, … Read more…

Untangling The Role Of Climate On Sediment And Reef Evolution Over Millennial Timescales

Climatic variability like precipitation changes or increase in extreme events such as storms and tropical cyclones is known to significantly modify the Earth’s surface. Yet, our understanding of how sediment dynamics and reef evolution might respond to these changes is still limited. In a recent study, a team of researchers from the University of Sydney’s … Read more…

Palaeolatitudinal distribution of lithologic indicators of climate in a palaeogeographic framework

Citation: Cao, W., Williams, S., Flament, N., Zahirovic, S., Scotese, C., and Müller, R. D., 2018. Paleolatitudinal distribution of lithologic indicators of climate in a paleogeographic framework. Geological Magazine, 1-24. Abstract: Whether the latitudinal distribution of climate-sensitive lithologies is stable through greenhouse and icehouse regimes remains unclear. Previous studies suggest that the palaeolatitudinal distribution of palaeoclimate … Read more…

Oceanic crustal carbon cycle drives 26 million-year atmospheric carbon dioxide periodicities

Citation: Müller, R.D. and Dutkiewicz, A., 2018, Oceanic crustal carbon cycle drives 26 million-year atmospheric carbon dioxide periodicities, Science Advances, 4:eaaq0500, 1-7. Atmospheric carbon dioxide (CO2) data for the last 420 million years (My) show long-term fluctuations related to supercontinent cycles as well as shorter cycles at 26–32 My whose origin is unknown. Periodicities of 26–30 … Read more…

Models are as hot as rocks!

In a recent paper in JGR-Solid Earth, EarthByter Ömer Faruk Bodur and colleagues show that mantle lithosphere rheology has a primary control on the subduction style (i.e., one-sided vs. double-sided subduction) and strongly affects the pressure-temperature conditions of metamorphic rocks that can be buried >100 km depth and exhume to the surface! This long journey … Read more…