How Much Did the Moon Heat Young Earth?

Tidal heating may have raised the surface temperature of early Earth and triggered global volcanism, a new study says.

How Extreme Apparitions of the Volcanic and Anthropogenic South East Asian Aerosol Plume Trigger and Sustain El Niño events using data from the Last Millennium Ensemble, Large Ensemble, MERRA-2 Reanalysis, four Satellites and the Global Volcanism P

<p>Volcanic aerosols over south east Asia have always been the trigger and sustaining cause of ENSO events. In recent decades this natural plume has been augmented by the anthropogenic plume which has intensified ENSO events especially in SON. Data from the Last Millennium Ensemble (13,872 months), and Large Ensemble (3,012 months) demonstrate this connection with three ENSO indices and aerosol data derived from the same datasets correlating at 1.00 (LME), 0.97 and 0.99 magnitude (segmented and averaged). ENSO events are the dominant mode of variability in the global climate responsible for Australian, Indian and Indonesian droughts, American floods and increased global temperatures. Understanding the mechanism which enables aerosols over SE Asia and only over SE Asia to create ENSO events is crucial to understanding the global climate. I show that the South East Asian aerosol Plume causes ENSO events by: reflecting/absorbing solar radiation which warms the upper troposphere; and reducing surface radiation which cools the surface under the plume. This inversion reduces convection in the region thereby suppressing the Walker Circulation and the Trade Winds which causes the SST to rise in the central Pacific Ocean and creates convection there. This further weakens/reverses the Walker Circulation driving the climate into an ENSO state which is maintained until the aerosols dissipate and the climate system relaxes into a non-ENSO state. Measured aerosol data from four NASA satellites, estimates of volcanic tephra from the Global Volcanism Program (GVP) for over 100 years and the NASA MERRA-2 reanalysis dataset all confirm this analysis.</p>

Usability of velocities of GNSS campaign measurements on volcano monitoring depending distance between station and volcano

<p>GNSS campaign measurements are often used for also volcano monitoring. The most important reason for this is that the permanent stations near the volcano are costly and likely to be damaged after the eruption. Often, even campaign measurements are risky near an active volcano. On the other hand, it would be low risky and low costly to make campaign measurements distant from volcano activities and eruptions. In this study, in order to expound the analysis results, we constituted our global test area using five IGS stations around five active volcano eruptions over 2019 via the Smithsonian Institute Global Volcanism Program. The data archives of the International GNSS service (IGS) and the time series of the Jet Propulsion Laboratory (JPL) were used for the purpose. And then we decimated the continuous data down to monthly and four monthly sampled GPS campaign time series. We also generated random values of ±3 mm for possible antenna setup errors. We tested whether the velocities obtained from monthly and four monthly solutions differ significantly from the velocities derived from daily solutions. As a result, we concluded on monthly velocities that horizontal components are compatible completely and 80% of the vertical components are compatible. We also concluded on four monthly velocities that 65% of the horizontal components are compatible and vertical components are compatible completely. We explained the utilization of campaign measurements in volcano monitoring by examining the effect of the distance between the stations and volcanoes on the results obtained.</p><p><strong>Keywords:</strong> Volcano Monitoring, GNSS Campaign Measurements.</p>

Heat Pipes and Vertical Tectonics in Terrestrial Planets

<p>Terrestrial planet mantles cannot transport the very high heat production in their early stages through subsolidus convection and instead produce voluminous melt that makes its way to the surface to transport the heat. This heat-pipe mode of heat transport implies a very different tectonics than either the rigid or mobile-lid tectonics driven by subsolidus convection. Although  similar to rigid-lid convection in that there is relatively little horizontal motion, heat-pipe lithospheres are by no means stagnant. Vertical transport through the continuous eruption of new material on the surface reaches rates of several mm/year (with significant spatial and temporal variations). This strongly impacts the shape of the geotherm, producing a cold and strong lid (despite the high heat flow). In addition, this vertical transport produces global compressional stresses as old surfaces are buried and forced downward to smaller radii. The horizontal variations in burial rates will lead to stress concentrations and ultimately plastic failure and thrusting (see Io’s numerous tectonic uplifts as an example). The transition from the advectively dominated heat-pipe lithosphere to a thin conductive lithosphere reverses this process, resulting in a period of global extension (again with large horizontal variations) as global volcanism wanes. An additional aspect of vertical transport in the heat-pipe lithosphere is the cycling of water and other volatiles into the lithosphere and mantle as surface materials are buried. This material is available for metamorphic reactions and will interact with rocks at the wet solidus, producing evolved rock compositions and volatile by-products (e.g. methane) that will contribute to the early atmospheres of these planets. Evidence of vertical transport in ancient Earth rocks has generally been attributed to subduction but heat-pipe advection provides a more global opportunity for such cycling.</p>

Global rates of continental volcanism on Earth

<p>Knowledge of the rates of Earth volcanism and their variability is critical in many fields involving global assessments, such as plate tectonics and associated rates of crustal formation and consumption, large-scale volcanic hazards, climate change, etc. Global rates also provide the base rate to which regional or individual volcano data can be compared, in order to quantify differences and similarities providing guidance in the identification of volcanoes with overall analogue behaviors. While global volcanic eruption databases, such as the Smithsonian Global Volcanism Project database or the Large Magnitude Explosive Volcanic Eruptions database at BGS, provide the required basic knowledge, substantial deterioration of the geologic information with age has been a serious obstacle to a comprehensive picture. Recent understanding that global eruption inter-event times are exponentially distributed, that being the essential character of Poisson distributed events, is leading to a general model for the global eruption behavior of the Earth. Exponential distributions are entirely characterized by one single rate parameter. Comparing the rate parameters for different VEI classes of eruptions, as well as analyzing the distribution of individual eruption volumes within and across different VEI classes, reveals that relative frequencies for the explosive eruptions with VEI higher than 2 distribute as a power law. This knowledge is employed a) to quantify the global volcanic hazard, in particular in relation to the occurrence of globally impacting eruptions, comparing with known hazards from many well-known adverse events; and b) within a Monte Carlo simulation of the eruptive history of the Earth, allowing us to quantify the distribution of volcanic eruption rates, both in number and volume, and globally or for each given VEI class or group of VEI classes, over different observational time windows from 1 to 100,000 years.</p>

Ooidal ironstones in the Meso-Cenozoic sequences in western Siberia: assessment of formation processes and relationship with regional and global earth processes

This study investigates the process of formation of ooidal ironstones in the Upper Cretaceous-Paleogene succession in western Siberia. The formation of such carbonate-based ironstones is a continuing problem in sedimentary geology, and in this study, we use a variety of data and proxies assembled from core samples to develop a model to explain how the ooidal ironstones formed. Research on pyrite framboids and geochemical redox proxies reveals three intervals of oceanic hypoxia during the deposition of marine ooidal ironstones in the Late Cretaceous to the Early Paleogene Bakchar ironstone deposit in western Siberia; the absence of pyrite indicates oxic conditions for the remaining sequence. While goethite formed in oxic depositional condition, chamosite, pyrite and siderite represented hypoxic seawater. Euhedral pyrite crystals form through a series of transition originating from massive aggregate followed by normal and polygonal framboid. Sediments associated with goethite-chamosite ironstones, encompassing hypoxic intervals exhibit positive cerium, negative europium, and negative yttrium anomalies. Mercury anomalies, associated with the initial stages of hypoxia, correlate with global volcanic events. Redox sensitive proxies and ore mineral assemblages of deposits reflect hydrothermal activation. Rifting and global volcanism possibly induced hydrothermal convection in the sedimentary cover of western Siberia, and released iron-rich fluid and methane in coastal and shallow marine environments. This investigation, therefore, reveals a potential geological connection between Large Igneous Provinces (LIPs), marine hypoxia, rifting and the formation of ooidal ironstones in ancient West Siberian Sea.