References for The Earth

• All volcanism begins in the mantle

• How the mantle is heated and rises

• Decompression melting and hydration melting at subduction zones

• Neutral buoyancy causing magma chambers where magma crystallises

Oppenheimer, 2011

• Mantle convection and plate tectonics work together in one system

• Upwelling of magma can create cracks in continents

• Radiometric dating shows magma is formed at different times due to recycling of former crust at subduction zones

• This occurs as slabs of the mantle sink to the core-mantle boundary where they sit in a ‘slab graveyard’ combining with thermal instabilities to form LLSVPs where plumes and mega plumes rise from

Tackley, 2000

• Mantle plume theory proposed in 1970s to explain intraplate hotspot volcanism

• Plumes begin at the core-mantle boundary and form trails as they experience partial melt

• Plumes have heads and tails, they rise due to hotter temperatures and being less dense due to chemical distinctions

• Plumes are unstable and move at different speeds and in different directions to break oceanic lithosphere and cause eruptions

Koppers et al., 2021

• Blobs form in the thermal boundary before destabilising and rising

• Once the plume reaches the Moho it gets trapped

• As the plume rises, latent heat is removed so it cools and becomes less buoyant, this can also occur due to residue below the lithosphere

Manglik & Christensen, 1997

• Plate tectonics link the surface and deep interior to allow for the exchange of elements needed for life on Earth

• The deep Earth stabilises habitability on Earth

• The main source of water on Earth comes from volcanic activities and upwelling making volcanism the main source of life

• Volcanic activity releases elements from the deep Earth that are bio-essential and creates food chains allowing for survival

• These all stop mass extinctions and support the conditions conducive to life on Earth

Wang et al., 2023

• Polymerisation of magma means it does not have a clear melting point, silicate polymers impact viscosity

• The variables of composition, pressure and volatile content combined with polymerisation mean partial melt occurs

• Crystallisation occurs in chambers, they can track changes and influence viscosity

• At subduction zones slabs sink and the water contained in the hydrated oceanic crust is expelled into the rising mantle wedge to lower melting points and promote melting

• Anomalous hotspots lead to mantle plumes up to 300 degrees hotter than the surrounding mantle

Francis & Oppenheimer, 2004

• The Gaia theory sees Earth as a global self-sustaining organism due to the holistic feedback systems regulating temperatures and gases

• AI could save the Gaia theory due to it’s intellectual powers aiding in understanding Earth’s systems and resilience mechanisms

Radford, 2019

• Aims to combine science with indigenous perspectives to allow for better conservation, mitigation and risk assessment

• Mount Ruapehu is seen as the place of Gods and the Life Force, Crate Lake supplies sustenance to the land

• The union of Father Sky and Mother Earth sees the land as the key value within the community and guards all domains of life

• Blending the scientific and indigenous knowledge can reduce social vunerability

Pardo et al., 2015

• Villagers are able to identify precursor events based on past knowledge and experiences

• The summit of the volcano on Ambae Island is seen as a sacred site so visits are forbidden as a form of hazard management

• The villagers live away from the streams to avoid flood risks and the paramount chief makes decisions in times of emergency, yet these are often miscommunicated due to political rivalries

Cronin et al., 2004

• The rights of nature has had the greatest impact in the Global South where Indigenous activism and lack of effective laws provide incentive for experimentation

• Ecuador is an example of a success

• A multi-disciplinary approach is needed to recognise where laws are needed and how they can be meaningful

Epstein et al., 2023

• The combination of sulphur and carbon outgassing from LIPs are key in impacting atmosphere and ocean circulation allowing for the survival of life on Earth

• Sulphur emissions are intense and occur in intervals to have net cooling impacts

• There are swings in climate as warmer carbon modes (the greenhouse effect) are followed by cooler sulphur modes (albedo effect) when sulphur is injected

• The swings impact hydrological cycling, weathering and ocean anoxia

• Sulphur aerosols have a shorter atmospheric residence than carbon so cannot have as longer term impact

Black et al., 2018

• Mt Pinatubo caused the largest perturbation of the century to particulate content in the stratosphere seeing temperatures drop as well as levels of stratospheric ozone

• The introduction of sulphuric acid aerosols increases planetary albedo due to more efficient scattering, they also act as condensation nuclei for clouds to reduce their size and increase secondary scattering efficiency

• Microphysical properties of aerosols determine their absorptivity, the Mt Pinatubo particles were very small so cooling dominated

• Coupling of volcanic chlorine emissions and anthropogenic CFCs caused ozone depletion

• This study allows models to be made more accurate and policy to be amended in the future to ensure greater quality of life

McCormick et al., 1995

• There is a robust link between LIPs and major environmental catastrophes which have been linked to mass extinctions, most effective links are between the Siberian Traps and the end-Permian and the Deccan Traps and the end-Creatceous

• LIPs can have direct and indirect effects through global warming, cooling, anoxia, toxic gas or metal release, acid rain, ocean acidification or oxygenation of the atmosphere

• Global warming is due to the release of isotopically light carbon gases from HVCs as well as methane emissions

• Global cooling is created through SO2 injections to the atmosphere, CO2 drawdown due to weathering of basalts and injections into the stratosphere causing volcanic winters

Ernst & Youbi, 2017

• The strongly acidic rain and global ozone collapse resulting from episodic volcanism and heating of volatile-rich Siberian rocks are possible causes for the end-Permian extinction event 

• The peak timing of marine extinctions lines up with the emplacement of the lava pile from the Siberian Traps, terrestrial extinction timing is less clear but appears to be synchronous

• Acid rain is modelled to have disfigured and stunted growth of plants in the NH as well as damaging marine ecosystems

• In the SH, depleted ozone levels led to higher levels of UV-B flux which can stunt plant growth 

• As the Siberian Traps magmatism was episodic, the fluctuations of pH and UV fluxes would have been rapid and outpace capacity for biological adaptation leading to extinction

Black et al., 2014

• Extratropical eruptions are thought to be less effective at driving large-scale surface cooling than tropical eruptions, but recent minor extratropical eruptions produce measurable impacts

• Since 750 CE extratropical eruptions have produced stronger hemispheric cooling than tropical eruptions due to the hemispheric confinement of aerosols

• There is higher cooling when aerosols are contained within one hemisphere, this overwhelms arguments for shorter lifetimes of stratospheric sulfur

• The aerosols become heavily concentrated in the NH so peak at higher values, faster and with longer term impacts

• This can aid in modelling and reconstructions of past eruptions

Toohey et al., 2019

• The communities become co-volcanic societies as the Filipino communities have become around Mount Mayon

• It has shaped human settlements through lava flows that decimate towns and force relocation, the most famous example is the 1814 eruption causing the survivors from Budiao and Cagsawa to move to Daraga

• Place names reflect the importance of the volcano such as Uson meaning a place of pyroclastic flows

• The volcano also created islands in the lowlands due to flash flooding, the micro-regions began to develop their own dialects and languages forming a sense of identity that exists today

• This also influences myths, rituals and ceremonies such as Mayon as the abode of Gugurang, the legend of Daragang Magayon or the Bugan holy figure warning of the eruption

• The Perdon practice sees women on a procession through the village for seven nights to ward off evil spirits from the volcano seeing it memorialised in ceremony 

Bankoff et al., 2021

• The Ngati Rangi indigenous tribe living on the southern flanks of Mount Ruapehu are familiar with the mood, signs and language of the mountains so have valuable knowledge to contribute to decision making 

• Knowledge has been under-utilised and tribes have not been included in decision making

• There are efforts to better recognise the knowledge, improve communications and work with local governments to improve outcomes for the tribe and local communities

Gabrielsen et al., 2017

• Sulphur emission is critical to producing strong climatic forcing, sulphur rich magmas have low sulphur solubility so very explosive eruptions tend to be silicic rather than basaltic; magmas must also be highly oxidising or highly reducing to have the highest sulphur emissions

• Eruptions must be explosive and intense enough to penetrate the stratosphere in order to stay aloft and have a significant effect on radiation

• The height of the tropopause varies being higher at the tropics meaning a more explosive eruption is needed to reach the stratosphere

• The polar vortex amplifies the global effect of tropical eruptions where atmospheric forcing limits the impact of high-latitude eruptions

• Seasonal variation is also important as a humid atmosphere is preferable to boost plumes higher into the atmosphere; the position of the ITCZ is also key as the proximity of an eruption cloud to the ITCZ can change the dispersal or aerosols, it moves north in NH summer and south in winter 

• El Nino of other climatic oscillations can also play a part

Oppenheimer, 2011

• Often the study of thermal processes within Earth is speculative as it is based on measurements made at or near the surface 

• Solar energy, the gradual deceleration of the Earth’s rotation and energy released by earthquakes are sources of energy but these only make up around 0.002% of the energy budget showing geothermal energy is the most important source

• Geothermal energy is derived in part from heat released during the early stages of the formation of the Earth 

• It is also extracted from the radioactive decay of long-lived isotope such as uranium and potassium in an exponential pattern of decay

Kearey et al., 2009

• Increasing precision of U-Pb dating a larger number of Phanerozoic boundaries making biotic crises can be correlated with LIPs, this provides backing for the use of LIPs as proxies for golden spikes

• LIPs have many impacts on the climate such as warming due to GHGs, cooling due to sulphur emissions and CO2 drawdown as well as ocean anoxia, ocean acidification, sea level changes and toxic metal input

• The precision of correlating LIPs to mass extinctions implies a causal mechanism, Proterozoic LIPs in particularly can be used to define natural boundaries

• The volume of an LIP is not the sole control on its impact, rate of effusion, abundance of pyroclastic material and volatile fluxes reaching the atmosphere are also important 

• Feedbacks play a part in magnifying environmental impacts as well as location as oceanic LIPs have smaller impacts due to the buffer effect of seawater

Ersnt et al., 2020

• Pulses of glaciation can be linked to LIP events, they can start glaciations due to cooling via SO2 injections and CO2 drawdown or end them due to GHG emissions; there is more research needed into this

• Ocean anoxia events see black shales of low or no oxygen in the deep ocean which have been linked with oceanic LIPs

• High CO2 and SO2 in the atmosphere can form acid rain in the form of carbonic and sulphuric acid as well as transferring to oceans to cause ocean acidification with the loss of calcified marine species

• The arrival of mantle plumes beneath the ocean and emplacement of oceanic plateaus causes sea level rise but as it decays sea levels fall again, continental LIPs at first form sea level falls but continental rifting than forms rises; global warming and glaciations can also affect sea water volumes and levels

• Toxic metals such as mercury can bind to clays and organic material to lead to malformation of plants and extinctions, depletion of bioessential elements and nutrients also has this effect 

• LIPs have also been linked to oxygenation of the atmosphere and ocean leading to life such as the Cambrian explosion

Ernst & Youbi, 2017