ORCID Profile
0000-0002-8216-8389
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Publisher: Copernicus GmbH
Date: 25-10-2019
Publisher: Copernicus GmbH
Date: 20-03-2020
Abstract: Abstract. The Earth is currently 180 Myr into a supercontinent cycle that began with the break-up of Pangaea and which will end around 200–250 Myr (million years) in the future, as the next supercontinent forms. As the continents move around the planet they change the geometry of ocean basins, and thereby modify their resonant properties. In doing so, oceans move through tidal resonance, causing the global tides to be profoundly affected. Here, we use a dedicated and established global tidal model to simulate the evolution of tides during four future supercontinent scenarios. We show that the number of tidal resonances on Earth varies between one and five in a supercontinent cycle and that they last for no longer than 20 Myr. They occur in opening basins after about 140–180 Myr, an age equivalent to the present-day Atlantic Ocean, which is near resonance for the dominating semi-diurnal tide. They also occur when an ocean basin is closing, highlighting that within its lifetime, a large ocean basin – its history described by the Wilson cycle – may go through two resonances: one when opening and one when closing. The results further support the existence of a super-tidal cycle associated with the supercontinent cycle and gives a deep-time proxy for global tidal energetics.
Publisher: Copernicus GmbH
Date: 23-03-2020
DOI: 10.5194/EGUSPHERE-EGU2020-5821
Abstract: & & We investigate two possible deep future Earth climate scenarios using a 3-D GCM [1], 200 and 250 million years into the future when the next supercontinent phase is expect to take place. We use knowledge of the evolution of plate tectonics, solar luminosity, and rotation rate over this time period.& & In one scenario, a supercontinent forms at low latitudes. In the other scenario it forms at high northerly latitudes with an Antarctic subcontinent remaining at the south pole.& & The climates differences between these two scenarios are dramatic, with differences in mean surface temperatures approaching 4 degrees. The fractional habitability (where mean surface temperatures are between 0& T& C year round) on land surfaces (as opposed to the ocean) is shown to differ up to 40% between the two simulations. We believe these demonstrate that the community needs to consider alternative boundary conditions when simulating Earth-like exoplanetary climates.& / & & & [1] Way et al. 2017, ApJS, 231, 21.& / &
Publisher: American Geophysical Union (AGU)
Date: 29-07-2021
DOI: 10.1029/2021GC009983
Abstract: We explore two possible Earth climate scenarios, 200 and 250 million years into the future, using projections of the evolution of plate tectonics, solar luminosity, and rotation rate. In one scenario, a supercontinent forms at low latitudes, whereas in the other it forms at high northern latitudes with an Antarctic subcontinent remaining at the south pole. The climates between these two end points are quite stark, with differences in mean surface temperatures approaching several degrees. The main factor in these differences is related to the topographic height of the high latitude supercontinents where higher elevations promote snowfall and subsequent higher planetary albedos. These results demonstrate the need to consider multiple boundary conditions when simulating Earth‐like exoplanetary climates.
Publisher: Copernicus GmbH
Date: 03-03-2021
DOI: 10.5194/EGUSPHERE-EGU21-1582
Abstract: & & Deep time investigations of the Earth have revealed a relationship between plate tectonic motion and the intensity of the tide. Tidal energetics change as continental plates disperse and aggregate in the supercontinent cycle, altering ocean basins around them. The question is, could enhanced tides occur on Earth before plate tectonics started e.g., during the Archean? & & & & & Here we have coupled an established tidal model with an ensemble of potential topographies of the Archean Earth to establish a statistically significant approximation of Archean tidal energetics. Land area is restricted to 5 & #8211 15% with the rest representing primordial ocean & #8211 containing no major plate tectonic features i.e., trenches and ridges. Ocean volume is preserved at close to present-day which means oceans are on average 1 km shallower than present-day oceans. Archean day length is set at 13.1 hours with the semi-diurnal tide occurring every 6.8 hours. Equilibrium tide is around 3.4x the present-day value due to the proximity of the Moon.& & & & The aim of this study is to assess the relationship of the Earth Moon system during this primordial stage to better understand the potential role tides had in the origin of life, and to quantify the tidal state of a primordial rocky planet with a young, nearby moon. Understanding the tidal state of Earth at this early time is important for exoplanetary studies as it broadens our scope of planets which may be hospitable to life.& & & & We found coastal and open ocean resonance in many of the ensemble topographies. Total global dissipation in the ensembles varies from 75 & #8211 150% of present-day dissipation rates due to elevated equilibrium tide and greater area where the tide can dissipate. When regional and open ocean resonance does occur, it can raise total global dissipation to & % of present-day values and can cause regional macrotidal litudes (& m).& &
Publisher: American Geophysical Union (AGU)
Date: 23-04-2018
DOI: 10.1002/2017GL076695
Publisher: Wiley
Date: 18-12-2019
Publisher: Copernicus GmbH
Date: 15-05-2023
DOI: 10.5194/EGUSPHERE-EGU23-8505
Abstract: On Earth, the characteristics of fluvial erosion depends on two main parameters: climate (rain fall) and tectonic history. Mars is a planet that experienced erosion driven by liquid water but its geodynamics are vastly different from Earth& #8217 s. Mars therefore represents a unique opportunity to understand how landscape evolution differs on a planet with a & #8220 stagnant lid& #8221 tectonic regime. The formation of Tharsis dome, a vast volcanic province, during the early history of Mars represented a major magmato-tectonic upheaval for the planet. Over several hundreds of million years, the Tharsis region experienced large scale magmatic intrusions, crustal deformation and effusive volcanism resulting in crustal growth, dynamic uplift and true polar wander (TPW) that accounts for the present location of the Tharsis dome at the equator. This event occurred during a time when Mars had an active water cycle, although the total mass and relative proportion of ice, liquid water and vapor is not well constrained. The uplift and subsequent true polar wander of Mars have affected drainage systems across the planet with many being abandoned or modified due to the variable uplift or subsidence as a lithospheric response to the regional upheaval in the Tharsis region (load on the elastic lithosphere) and TPW. Here we present results from numerical simulations performed using a stream power law algorithm on Mars during the Noachian/Hesperian growth of Tharsis to assess how the patterns of erosion rate are affected by the distribution of atmospheric moisture and flow routing in an attempt to reproduce the observed distribution of valley networks and their geometry. For this, we adapted and used the fully-implicit and O(n)-complexity FastScape algorithm to perform the simulation at the planetary scale. The aims of this work are to quantify the effect of Tharsis dome formation on fluvial systems during the Noachian and early Hesperian, and to establish a first-order erosion rate for this period. This study could help to constrain how much water was cycling on Mars at this time.
Publisher: Copernicus GmbH
Date: 25-10-2019
DOI: 10.5194/ESD-2019-61
Abstract: Abstract. The Earth is currently 180 Ma into a supercontinent cycle that began with the breakup of Pangea, and will end in around 200–250 Ma (Mega-annum) in the future, as the next supercontinent forms. As the continents move around the planet, they change the geometry of ocean basins, and thereby modify their resonant properties. In doing so oceans move through tidal resonance, causing the global tides to be profoundly affected. Here, we use a dedicated and established global tidal model to simulate the evolution of tides during four future supercontinent scenarios. We show that the number of tidal resonances on Earth vary between 1 and 5 in a supercontinent cycle, and that they last for no longer than 20 Ma. They occur in opening basins after about 140–180 Ma, an age equivalent to the Present-Day Atlantic Ocean, which is near resonance for the dominating semi-diurnal tide. They also occur when an ocean basin is closing, highlighting that in its lifetime, a large ocean basin – its history described by the Wilson cycle – may go through two resonances: one when opening and one when closing. The results further support the existence of a super-tidal cycle associated with the supercontinent cycle, and gives a deep-time proxy for global tidal energetics.
Publisher: Wiley
Date: 23-06-2021
Publisher: Copernicus GmbH
Date: 27-03-2022
DOI: 10.5194/EGUSPHERE-EGU22-4019
Abstract: & & The supercontinent cycle and Wilson cycle describe the periodic formation and termination of supercontinents and ocean basins respectively. This cyclicity has occurred since the beginning of the Phanerozoic, however, it may have been active in some form much earlier (i.e., during the Proterozoic). The periodic opening and closing of ocean basins following the Wilson cycle has been found to affect the tides, as oceans grow and shrink over geological time, they occasionally allow open ocean tidal resonance to occur. These resonant periods are relatively short lived (~ 20 Ma) however, they profoundly affect the tidal energy budget of the planet while active. & & & & & We have now investigated the relationship between tides and & #8220 late tectonics& #8221 during the Archean, Paleo-Proterozoic, Cryogenian, Ediacaran, Devonian, and during conceptualised future supercontinent scenarios. We find that periods of open ocean tidal resonance occur much more frequently in our tidal models after ~600 Ma. While earlier periods of Earth history where the Moon was physically closer produce higher relative tides, later periods such as the Ediacaran, Devonian and present day produce higher tides through open ocean resonance. This trend continues into the near future, with open ocean resonance likely occurring multiple times before the formation of the next supercontinent. Notwithstanding, the Cryogenian period represents an outlier in this trend, with very low tidal dissipation rates. We conclude that this is due to the global & #8220 snowball& #8221 glaciations of the time supressing the tide. Despite the Cryogenian outlier, our results are consistent with other deep-time modelling studies.& & & & The result of the Cryogenian, and the disparity in time between periods which we have tidally modelled, show that more work is needed to fully reconstruct the tidal environment of the Earth in deep-time. Filling in the missing periods with tidal modelling efforts and including the effect of other components of the Earth system, (i.e., glacial periods/climate, orbital parameters, and tectonic setting) are all needed to establish a robust record of the tide in deep-time. This can then be further validated with other models and geological data of the tide to help us better understand Lunar orbital evolution, and the Earth system in the past and potentially in the future.& &
Publisher: Copernicus GmbH
Date: 23-03-2020
DOI: 10.5194/EGUSPHERE-EGU2020-10775
Abstract: & & In an era where communicating your science goes hand in hand with doing your science, many scientists devote time to develop tools and learn new skills and strategies for Science Communication. The European Geosciences Union (EGU) has put in place one of those tools: the Divisions& #8217 Blog. Most of the current EGU Divisions has an active blog run mainly by one or more volunteer early-career scientists.& & br& Regularly, both editors, and regular and guest authors write about research in their field, talk about relevant topics discussed within the scientific community, and highlight interesting facts for scientists and the general public. The goal is to provide a platform for enhancing communication among geoscientists in ways that go beyond the means of peer-reviewed publication or scientific conferences. At the same time, we aim at engaging with the general public, by writing in a technically sound, but more accessible form. Each Division& #8217 s blog has its character, like the teams behind it, making the blogs a ersified and exciting digital environment.& & & & Here we show the main numbers, statistics, and feedback from each Division Blog, thus providing a measure of the efforts put in and the impact made so far by the broad Geoscience community. We discuss best practices, blog styles and topics which do work well or not, based on readership statistics. We also show the channels chosen for advertising the blogs, such as social media, and the impact of the choices made. Finally, we show that even though EGU has its base in Europe, we reach an audience beyond Europe thanks to active members based outside Europe and to topics addressing particular geographical areas.& & & & We conclude that, within the increasingly essential role played by Science Communication in every research field, the EGU Divisions& #8217 Blogs are successful at sharing research related to their fields with the broad geoscientific and non-scientific community. This success mainly relies on the time, effort, motivation, and creativity of editors and guest authors.& &
Publisher: Copernicus GmbH
Date: 03-03-2021
DOI: 10.5194/EGUSPHERE-EGU21-1354
Abstract: & & The severe & #8220 Snowball Earth& #8221 glaciations proposed to have existed during the Cryogenian period (720 to 635 million years ago) coincided with the breakup of one supercontinent (Rodinia) and assembly of another (Pannotia). The presence of extensive continental ice sheets should theoretically lead to a tidally energetic Snowball ocean due to the reduced ocean depth, as was the case during the last glaciations, but the theory of the supertidal cycle suggests that the supercontinent paleogeography should lead to weak tides because the surrounding ocean is too large to host tidal resonances. So which theory is correct? Using an established numerical global tidal model and 22 paleogeographic reconstructions spanning 750-600Ma, we show that the Cryogenian ocean hosted diminished tidal litudes and associated energy dissipation rates, reaching 10-50% of today& #8217 s rates, during the Snowball glaciations. In contrast, the tides were more energetic during the ice-free periods, and we propose that the near-absence of Cryogenian tidal processes may have been one contributor to the prolonged glaciations if these were near-global. These results also constrain lunar distance and orbital evolution throughout the Cryogenian and highlight that simulations of past oceans should include explicit tidally driven mixing processes.& &
Publisher: Copernicus GmbH
Date: 23-03-2020
DOI: 10.5194/EGUSPHERE-EGU2020-596
Abstract: & & Recent research of coupled tidal and tectonic modelling has found that during periods in an ocean& #8217 s Wilson cycle, (i.e. during dispersal, and subsequent convergence of oceans due to plate tectonic movement), oceans occasionally become resonant for the semi-diurnal component of the tide (M& sub& & /sub& ). This results in an approximately 20-Million-year long period of enhanced tidal dissipation in the resonant ocean (assuming continental plate drift rates of ~5 cm yr& sup& -1& /sup& ). This resonant & #8220 Super-tide& #8221 has been simulated in numerical tidal models for both past and future tectonic scenarios, and they show that the current tides are among the most energetic found.& & & & Here we use an established tidal model to analyse the conditions required for open ocean tidal resonance. Our conceptual & #8220 Earths& #8221 consist of two or more simplified oceans, which are shaped to represent conceptual versions of oceans of the past, present, and future: triangular (Tethys ocean), circular (Pacific and Arctic oceans), rectangular (Southern and Indian oceans), and rhomboid shaped (North, and South Atlantic Ocean). Each scenario was conducted using ocean bathymetry ranging from a & #8220 bathtub& #8221 ocean (a uniformly deep flat abyssal plane from coast to coast), to a continental shelf with no abyssal bathymetry, to a & #8220 realistic& #8221 ocean with ocean shelves, ridges, and subduction zones. The global ocean land ratio and ocean volume was conserved to present-day in most conceptual scenarios however, to investigate the maximum tidal dissipation possible on Earth, some scenarios deviated from the ocean volume and global coverage. In every scenario, ocean width is progressively increased relative to the predominant ocean boundaries, simulating plate tectonic opening of each ocean.& & & & The aim of the work was to assess the frequency of the occurrence of resonance in the open ocean, and the upper limit for tidal dissipation of the semi-diurnal tide on Earth. We found that super-tides are common in the results with their dissipative strength varying from weaker than present day to five times present day.& & & & The occurrence of tidal resonances in modelled conceptual oceans further confirms the link between tectonics and tidal evolution. These super-tidal periods of markedly increased tidal dissipation alter the ocean& #8217 s energy budget, nutrient dispersal and the carrying capacity of coastal and oceanic ecosystems.& &
Publisher: Elsevier BV
Date: 10-2018
Location: Germany
No related grants have been discovered for Hannah Sophia Davies.