Earth's climate may be stabilized over millennia by solubilization of atmospheric carbon dioxide (CO2) as minerals weather, but the temperature sensitivity this thermostat is poorly understood. We discovered that dependence weathering expressed an activation energy increases from laboratory to watershed transport, clay precipitation, disaggregation, and fracturing increasingly couple dissolution. A simple upscaling global system indicates decreases ~22 kilojoules per mole because (i) lack...

The base of the Critical Zone includes mantle altered soil and rock—regolith—that changes in response to chemical, physical, biological processes occurring at Earth's surface. These are recorded chemistry regolith, this long-term record can often be deciphered. For example, on eroding ridgetops where flows generally downward for water upward earth material, element concentrations vary with depth constitute depletion, addition, depletion-enrichment, biogenic profiles. Models used explore...

Abstract It has been hypothesized that many soil profiles reach a steady‐state thickness. In this work, such were simulated using one‐dimensional model of reaction with advective and diffusive solute transport. A ‘rock’ is considered, consisting albite weathers to kaolinite in the presence chemically inert quartz. The yields three different regimes weathering. At lowest erosion rates, local‐equilibrium regime established where completely depleted weathering zone. This equivalent...

ABSTRACT Weathering disaggregates rock into regolith – the fractured or granular earth material that sustains life on continental land surface. Here, we investigate what controls depth of formed ridges two compositions with similar initial porosities in Virginia (USA). A priori , predicted diabase would be thicker than granite because dominant mineral (feldspar) weathers faster its granitic counterpart. However, weathering advanced 20× deeper diabase. The 20 × ‐thicker is attributed mainly...

ABSTRACT Landscape curvature evolves in response to physical, chemical, and biological influences that cannot yet be quantified models. Nonetheless, the simplest models predict existence of equilibrium hillslope profiles. Here, we develop a model describing steady‐state regolith production caused by mineral dissolution on hillslopes which have attained an parabolic profile. When lowers at constant rate, rate chemical weathering is highest ridgetop where ridge develops thickest regolith. This...

Abstract We explore the contribution of fractures (joints) in controlling rate weathering advance for a low‐porosity rock by using methods homogenization to create averaged equations. The front can be expressed as same observed non‐fractured media (or an individual block) divided volume fraction blocks fractured parent material. In model, has that are filled with more porous material contains only inert or completely weathered weathers reaction‐transport processes. As field systems, model...

Abstract Weathering of bedrock creates and occludes permeability, affecting subsurface water flow. Often, weathering intensifies above the table. On contrary, can also commence below To explore relationships between table, a simplified model for an eroding hillslope was formulated that takes into account both saturated unsaturated flow (but does not fully changes in dissolved gas chemistry). The phreatic line calculated using solutions to mathematical treatments zones. In model, infiltration...

Abstract Knowing little about how porosity and permeability are distributed at depth, we commonly develop models of groundwater by treating the subsurface as a homogeneous black box even though vary with depth. One reason for this depth variation is that infiltrating meteoric water reacts minerals to affect in localized zones called reaction fronts. We beginning learn map model these fronts beneath headwater catchments show they distributed. The landscapes defined lie subparallel soil‐air...

Bifurcation analysis is introduced to a prototype Liesegang ring (LR) model explain pattern formation as an instability of propagating plane reaction front. A theoretical criterion for the onset patterning derived and numerically tested. The uneven spacing law LR bands explained consequence time varying velocity moving Suggestions controlling are provided.

ABSTRACT We present a model of chemical reaction within hills to explore how evolving porosity (and by inference, permeability) affects flow pathways and weathering. The consists hydrologic reactive‐transport equations that describe alteration ferrous minerals feldspar. These reactions were chosen because previous work emphasized oxygen‐ acid‐driven weathering differently in felsic mafic rocks. A parameter controlling the order fronts is presented. In absence erosion, two move at different...

Microchemical devices exhibit a wide spectrum of length and time scales. In this paper, we discuss hierarchical multiscale simulation structured microreactors with square posts. Semiempirical models are used in conjunction density functional theory to develop quantitative microkinetic models. Sensitivity Analysis (SA) posteriori zero-order asymptotics employed derive one-step reaction rate expression that enables efficient computational fluid dynamics (CFD) simulations. The effects catalyst...

Abstract In this paper we clarify that our weathering model from 2013 did not explicitly describe of soil moving downhill along hillslopes. addition, re‐analyze the role term neglected describes loss regolith mass through mineral dissolution. We derive an equation for by including lateral flow water inside hill. For revised hill model, define a dimensionless parameter allows estimation effect on steady‐state hillslope. This is equal to ratio averaged advective flux dissolved species out rate...

A model for the spontaneous formation of patterned deposits in porous media, reminiscent Liesegang rings (LR) gels, is presented. Simulations show that under certain conditions frontal deposition a continuous solid film changes to quasi-periodic pattern bands. Bifurcation analysis simpler, skeleton explains LR as instability uniformly propagating plane reaction front time periodic solution. theoretical stability criterion developed suggests key parameters are critical concentration...

Despite its importance, only a few researchers have incorporated the effects of fracturing into models reactive transport for rock weathering. Here we explore 2D simulations that describe weathering under conditions diffusive and advective within heterogeneous media consisting rocky blocks fractures. In our simulations, Darcy velocities vary in space time depend on processes matrix. We with saturated unsaturated flow bedrock consists separated by inert or weathered material. The show...