Rapid Sedimentation
And Rapid Erosion

A Measurement-First Examination of
Geological Process

Purpose

This investigation asks no chronological question. It examines what sediment and rock demonstrably do under measured physical conditions. Where a process can be observed, reproduced, measured or identified structurally, that process is reported without attaching an age to it. The purpose is not to defend or oppose a historical framework. The purpose is to identify the physical work being done.

The organizing principle is pressure. Pressure is not restricted to gravitational loading. Hydraulic flow, compression, confinement, differential loading, tectonic stress, impact, thermal conditions, fluid movement and related physical interactions can all produce pressure capable of moving, sorting, depositing, deforming, compacting, eroding and redistributing material.

The Evidence Retrieved

Controlled hydraulic flume experiments. Sediment-laden flows produced sorting, grading, lamination, vertical organization and distinct deposits within minutes. Organized stratification therefore does not require slow accumulation merely because the resulting deposit is orderly.

Measured climbing-ripple deposition. Hydraulic sedimentation units tens of centimeters thick have been measured or reconstructed as accumulating during individual turbidity-current events lasting tens of minutes. Cross-lamination and ordered bedding can therefore be products of rapid deposition.

The 1929 Grand Banks turbidity current. A historically timed submarine current transported enormous quantities of sediment across extraordinary distances within hours. The event demonstrates that large-scale sediment transport and deposition can occur rapidly over geographic distances far beyond the laboratory.

Mount St. Helens. Direct observation after the 1980 eruption recorded rapid deposition, stratification, erosion, channel development, sediment transport, scour, refill and redeposition. The sequence was witnessed on a human clock and demonstrates that complex sedimentary and erosional architecture can develop rapidly.

Tapeats Sandstone. The physical architecture of the Tapeats records energetic moving water: large cross-beds, channels, cut-and-fill structures, bedload transport, changing flow directions, reactivation surfaces and repeated sediment reworking. The formation therefore preserves extensive hydraulic activity.

Coconino track experiments. Controlled experiments with animals moving across dry, wet and submerged sand demonstrated that important characteristics of Coconino fossil trackways can be reproduced under wet and submerged conditions. The tracks cannot be treated as a simple clock or as an uncomplicated indicator of dry deposition.

Coconino soft-sediment deformation. Presently lithified Coconino Sandstone preserves folds, rotated blocks, ridges and other structures demonstrating that portions of the formation were deformable before final lithification. Present solidity therefore cannot be projected backward automatically to the time when those structures formed.

Muav and Bright Angel relationship. Intertonguing between carbonate and siliciclastic units demonstrates overlapping depositional relationships rather than mechanically isolated, fully completed slabs. The physical boundary records changing depositional conditions across space.

Redwall Limestone. Petrographic evidence records early diagenetic mineral changes occurring at or near the depositional environment. Lithification is therefore a process that can begin early rather than a single late event separated from deposition.

The Great Unconformity. The physical surface records truncation, erosion, relief and subsequent deposition. These are process observations. The geometry of the surface itself records what happened physically; it is not, by itself, a clock.

Regional continuity and elevation change. Laterally persistent stratigraphic units change elevation together across regional structures. This demonstrates that an assembled package of strata subsequently underwent deformation. The geometry establishes sequence: deposition preceded the shared deformation.

Carbon Canyon Tapeats fold. Tapeats beds bend through a major change in orientation while reported petrography shows comparatively little of the pervasive hinge-centered microscopic damage expected from strongly deforming a fully cemented quartz-rich sandstone. Much of the present quartz cement appears compatible with cementation after the principal deformation.

Carbon Canyon fracture distribution. Fractures occur in hinges, limbs and distal control samples rather than showing a simple systematic concentration at the fold hinge. Their mere presence therefore does not identify them as products of the principal folding event. Fracture timing must be established from structural relationships.

Later seismic and brittle damage. A presently lithified formation can acquire fractures after its principal deformation through later fault movement, seismic activity, unloading, weathering, stress release or other events. A crack observed today cannot be assigned automatically to the event that produced an older fold.

Experimental and natural deformation of lithified sandstone. When already cemented quartz-rich sandstone is strongly deformed, strain is ordinarily recorded through systematic microfracturing, grain deformation, pressure solution, cement disruption, crystal-plastic strain, crushing or related mechanisms. Confining pressure can change the mode of deformation, but it does not make strain mechanically invisible.

What the Combined Evidence Says

These lines of evidence were obtained from controlled experiments, historically observed events, field relationships, sedimentary structures and petrographic examination. They converge on a common physical picture. Hydraulic pressure can move large quantities of material rapidly. It can sort that material while it moves. It can produce ordered layers, graded beds, ripples, cross-stratification, channels, scour surfaces and refill structures. Subsequent pressure can erode those deposits, transport them again and redeposit them elsewhere.

The investigation also establishes that present-day lithification cannot be assumed to describe the mechanical state of a formation during an earlier event. Some Grand Canyon strata preserve direct evidence of deformation while sediment was still soft or incompletely lithified. In other cases, the timing of cementation relative to deformation remains a petrographic question that can be tested from the rock fabric itself.

The regional geometry adds another constraint. Where multiple formations maintain their stratigraphic relationships while changing elevation together, the package must have existed before that shared deformation. Whether the material was loose, partly consolidated or fully lithified during the deformation must then be determined independently from its mechanical record rather than assumed from its present condition.

Pressure as the Physical Agent

Pressure provides the common physical language connecting these observations. Hydraulic pressure transports and sorts sediment. Differential pressure drives erosion and scour. Confining and tectonic pressures deform material. Pore-fluid pressure can permit liquefaction and soft-sediment deformation. Compaction and fluid movement participate in cementation and lithification. The same general physical category can therefore produce very different geological consequences according to material, geometry, confinement, temperature, fluid content and magnitude.

This does not make pressure a substitute for detailed mechanism. It makes pressure the governing physical condition whose particular expression must be measured in each case.

Finding

Across laboratory experiments, historically observed events, field structures and petrographic examination, rapid sedimentation and rapid erosion repeatedly emerge as predominant physical features of the evidence examined.

Organized strata can form rapidly. Large sediment volumes can move rapidly. Erosion, scour, transport and redeposition can occur rapidly. Substantial deformation can occur before final lithification. Later lithification does not establish the mechanical condition of material when an earlier structure formed.

Rapid is a description of an observed process, not an assertion of an age.

The investigation therefore terminates where the physical evidence terminates. No chronology is assigned.

The measured and observed processes are allowed to state their own result: rapid sedimentation and rapid erosion are powerful, recurrent and predominant expressions of pressure within the geological evidence examined.

Produced by The Lilborn Equation Team:

Michael Lilborn-Williams

Thomas Jackson Barnard

Audrey Williams