On mass transport in porosity waves

Jordan, Jacob S.; Hesse, M. A.; Rudge, John F.

doi:10.1016/j.epsl.2017.12.024

Cited by 24 publications

(29 citation statements)

References 57 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In geodynamic settings such as mid-ocean ridges, hotspots, subduction zones, or orogenic belts partial melts are generated within the asthenosphere or lower continental crust and ascend by fluid migration within deforming rocks (e.g., Sparks and Parmentier, 1991;Katz, 2008;Keller et al, 2017;Schmeling et al, 2019). Inherent tectonic or rock heterogeneities in such systems may result in spatially varying melt fractions on length scales varying over several orders of magnitudes.…”

Section: Introductionmentioning

confidence: 99%

Magma ascent mechanisms in the transition regime from solitary porosity waves to diapirism

Dohmen

Schmeling

2021

Solid Earth

View full text Add to dashboard Cite

Abstract. In partially molten regions inside the Earth, melt buoyancy may trigger upwelling of both solid and fluid phases, i.e., diapirism. If the melt is allowed to move separately with respect to the matrix, melt perturbations may evolve into solitary porosity waves. While diapirs may form on a wide range of scales, porosity waves are restricted to sizes of a few times the compaction length. Thus, the size of a partially molten perturbation in terms of compaction length controls whether material is dominantly transported by porosity waves or by diapirism. We study the transition from diapiric rise to solitary porosity waves by solving the two-phase flow equations of conservation of mass and momentum in 2D with porosity-dependent matrix viscosity. We systematically vary the initial size of a porosity perturbation from 1.8 to 120 times the compaction length. If the perturbation is of the order of a few compaction lengths, a single solitary wave will emerge, either with a positive or negative vertical matrix flux. If melt is not allowed to move separately to the matrix a diapir will emerge. In between these end members we observe a regime where the partially molten perturbation will split up into numerous solitary waves, whose phase velocity is so low compared to the Stokes velocity that the whole swarm of waves will ascend jointly as a diapir, just slowly elongating due to a higher amplitude main solitary wave. Only if the melt is not allowed to move separately to the matrix will no solitary waves build up, but as soon as two-phase flow is enabled solitary waves will eventually emerge. The required time to build them up increases nonlinearly with the perturbation radius in terms of compaction length and might be too long to allow for them in nature in many cases.

show abstract

Section: Introductionmentioning

confidence: 99%

Magma ascent mechanisms in the transition regime from solitary porosity waves to diapirism

Dohmen

Schmeling

2021

Solid Earth

View full text Add to dashboard Cite

show abstract

“…Melt derived from fertile domains could promote channelization (e.g., Katz & Weatherley, ; Lundstrom et al, ; Weatherley & Katz, ) or magmatic waves. Jordan et al () has shown that solitary magmatic waves may be able to trap and transport geochemical signals in isolation from surrounding melts. Hence, it seems likely that a comprehensive explanation for geochemical variations in erupted basalts should account for both source and transport heterogeneity, and their interaction.…”

Section: Discussionmentioning

confidence: 99%

“…Channels are hypothesized to transport deep, low-degree, enriched melts to the surface without aggregating the depleted melts that are produced at shallower depths (Spiegelman & Kelemen, 2003). Magmatic solitary waves may also be capable of transporting deep, enriched melts in isolation from those produced shallower (Jordan et al, 2018).…”

Section: Introductionmentioning

confidence: 99%

The Melting Column as a Filter of Mantle Trace‐Element Heterogeneity

Katz

Shorttle

et al. 2018

Geochem Geophys Geosyst

Self Cite

View full text Add to dashboard Cite

The observed variability of trace‐element concentration in basaltic lavas and melt inclusions carries information about heterogeneity in the mantle. The difficulty is to disentangle the contributions of source heterogeneity (i.e., spatial variability of mantle composition before melting) and process heterogeneity (i.e., spatial and temporal variability in melt transport). Here we investigate the end‐member hypothesis that variability arises due to source heterogeneity alone. We model the attenuation of trace‐element variability introduced into the bottom of a one‐dimensional, steady‐state melting column. Our results show that the melting column can be considered to be a filter that attenuates variability according to the wavelength of heterogeneity, the partition coefficient of the trace element, melt productivity, and the efficiency of melt segregation. We further show that while the model can be fit to the observations, this requires assumptions inconsistent with constraints on the timescales of magma assembly. Hence, we falsify the end‐member hypothesis and, instead, conclude that observed variability requires heterogeneity of melt transport. This might take the form of channels or waves and would almost certainly interact with source heterogeneity.

show abstract

“…Porosity waves were suggested to be a fast and efficient fluid transport mechanism forming various focused fluid flow structures (Appold & Nunn, 2002; Barcilon & Richter, 1986; Cai & Bercovici, 2013; Connolly & Podladchikov, 2015; Jordan et al, 2018; Mckenzie, 1984; Räss et al, 2014; Richard et al, 2012; Scott & Stevenson, 1984; Yarushina, Podladchikov, et al, 2015). Most of the previous models ignored the influence of deviatoric stresses on wave propagation, assuming that there is no shear or deviatoric stresses in the rock.…”

Section: Porosity Waves In the Presence Of Shearmentioning

confidence: 99%

Section: Porosity Waves In the Presence Of Shearmentioning

confidence: 99%

Model for (De)Compaction and Porosity Waves in Porous Rocks Under Shear Stresses

2020

View full text Add to dashboard Cite

An understanding of instantaneous and long‐term compaction of porous rocks is important for reservoir engineering and Earth sciences. Experience from laboratory triaxial compression tests and from subsurface operations indicates that shear and volumetric deformations are interdependent. Their mutual dependence results in shear‐enhanced compaction and shear‐induced dilation under short‐term and long‐term loading. Using a classical averaging approach, we consider the evolution of a single fluid‐filled pore in a solid elastoplastic or viscoplastic matrix under combined pressure and shear loading to introduce a new failure envelope and 3‐D constitutive relations for both rate‐dependent and rate‐independent deformation of porous rocks. Our model provides a simple description of rock behavior under a wide range of strain rates. The model predictions agree well with experimental data from triaxial instantaneous and creep tests. Analytical and numerical solutions for solitary porosity wave propagation in viscoplastic rocks in the presence of shear were obtained. New solutions show that new rheological laws have serious implications for porosity waves. Plasticity onset leads to compaction‐decompaction asymmetry and the formation of elongated channel‐like porosity waves. Shear‐induced dilation facilitates porosity wave propagation at fluid pressures below the lithostatic stress. This makes porosity waves a viable mechanism in the formation of focused fluid flow structures in crustal rocks.

show abstract

On mass transport in porosity waves

Cited by 24 publications

References 57 publications

Magma ascent mechanisms in the transition regime from solitary porosity waves to diapirism

Magma ascent mechanisms in the transition regime from solitary porosity waves to diapirism

The Melting Column as a Filter of Mantle Trace‐Element Heterogeneity

Model for (De)Compaction and Porosity Waves in Porous Rocks Under Shear Stresses

Contact Info

Product

Resources

About