Concepción Shelf Sedimentation Analysis

📊

Average Rate

2.8 mm/yr

Holocene average across shelf

🏞️

Terrigenous Input

75%

River and coastal erosion

🦠

Biogenic Input

25%

Marine productivity

⚡

Seasonal Variation

±40%

Winter vs summer rates

Sedimentation Rate vs Depth Profile

Depth Zone Analysis

Inner Shelf (0-30m)

High energy, coarse sediments

4.2 mm/yr

Mid Shelf (30-70m)

Moderate energy, mixed sediments

2.8 mm/yr

Outer Shelf (70-100m)

Low energy, fine sediments

1.5 mm/yr

Controlling Oceanographic Processes

🌊 Current-Driven Transport

• Peru-Chile Current: Northward transport
• Coastal undercurrent: Southward transport
• Cross-shelf exchange
• Tidal resuspension cycles

💨 Wind-Wave Effects

• Wave-induced bottom stress
• Seasonal storm resuspension
• Upwelling-driven circulation
• Ekman transport patterns

🏔️ Terrestrial Inputs

• Biobío River discharge
• Coastal cliff erosion
• Seasonal flood events
• Anthropogenic contributions

🦠 Biological Processes

• Upwelling-driven productivity
• Diatom blooms and settling
• Bioturbation effects
• Organic matter preservation

🌡️ Seasonal Cycles

• Winter storm intensification
• Summer upwelling maxima
• River discharge variability
• Temperature stratification

🌀 Climate Variability

• ENSO impact on sedimentation
• PDO long-term modulation
• Extreme event contributions
• Anthropocene acceleration

Sediment Source Contributions

Source Parameters

Biobío River Discharge (m³/s)

200 1100 2000

Coastal Erosion Rate (mm/yr)

0.5 2.75 5.0

Marine Productivity (gC/m²/day)

0.5 1.75 3.0

Terrigenous Sources

Biobío River

45%

Suspended sediment load: 2.1 Mt/yr

Coastal Erosion

30%

Cliff retreat: 2.1 mm/yr

Atmospheric Input

5%

Dust and volcanic ash

Biogenic Sources

Diatom Production

15%

Upwelling-driven blooms

Carbonate Production

3%

Foraminifera and mollusks

Organic Matter

2%

Marine and terrestrial

Grain Size Distribution

Clay (<4μm): 25%

Silt (4-63μm): 45%

Fine Sand (63-250μm): 22%

Medium Sand (250-500μm): 6%

Coarse Sand (>500μm): 2%

Seasonal Source Variability

Transport Mechanisms

Current Velocity (cm/s)

5 27.5 50

Wave Height (m)

0.5 3.25 6.0

Bottom Roughness (cm)

0.1 2.55 5.0

Transport Capacity

Suspended Load

1.2 kg/m³

Fine particles in water column

Bedload Transport

0.08 kg/m/s

Bottom sediment movement

Critical Shear Stress

0.15 N/m²

Threshold for erosion

Current-Driven Transport

Wave-Induced Transport

Transport Process Analysis

Advection

65%

Current-driven transport

Diffusion

20%

Turbulent mixing

Settling

12%

Gravitational deposition

Resuspension

3%

Wave-induced erosion

Spatial Deposition Patterns

Deposition Controls

Water Depth (m)

10 55 100

Distance from Shore (km)

1 8 15

Bottom Slope (degrees)

0.1 2.55 5.0

Deposition Rates by Zone

Nearshore (0-20m): 5.2 mm/yr

Inner Shelf (20-50m): 3.1 mm/yr

Mid Shelf (50-80m): 1.8 mm/yr

Outer Shelf (80-100m): 0.9 mm/yr

Sediment Accumulation

Total Accumulation

2.8 mm/yr

Shelf-wide average

Net Deposition

2.1 mm/yr

After erosion losses

Preservation Efficiency

Burial Efficiency

75%

Sediment preservation

Reworking Index

0.25

Sediment mobility

Temporal Deposition Variability

Sedimentation Rate Calculator

Sediment Supply (kg/m²/yr)

Bulk Density (g/cm³)

Porosity (%)

Compaction Factor

Erosion Rate (%/yr)

Bioturbation Depth (cm)

Calculation Results

Gross Sedimentation Rate

3.2 mm/yr

Before erosion and compaction

Net Sedimentation Rate

2.7 mm/yr

After erosion losses

Compacted Rate

2.3 mm/yr

Final burial rate

Mass Accumulation Rate

3.7 g/cm²/kyr

Dry weight basis

Sensitivity Analysis

Parameter Influence

Sediment Supply: 45%

Erosion Rate: 25%

Bulk Density: 15%

Porosity: 10%

Compaction: 5%

Uncertainty Analysis

Model Uncertainty

±15%

Parameter variability

Measurement Error

±8%

Analytical precision

Spatial Variability

±25%

Across shelf variation

Temporal Variability

±40%

Seasonal/interannual

3D Sediment Distribution Model

🏔️

3D Shelf Model

Interactive sediment thickness visualization

Model Parameters

Time Period (years)

Resolution (m)

Climate Scenario

Sediment Thickness

Maximum Thickness

28 m

Inner shelf depocenters

Average Thickness

12 m

Shelf-wide mean

Total Volume

2.1 km³

Holocene accumulation

Isopach Analysis

Model Statistics

Grid Points: 15,000

Time Steps: 10,000

Model R²: 0.87

RMSE (mm/yr): 0.3

Cross-Shelf Sediment Profile

Model Validation

Core Data Comparison

Good Agreement

15 sediment cores analyzed

Radiometric Dating

¹⁴C & ²¹⁰Pb Validated

Age model constraints

Seismic Stratigraphy

Reflector Correlation

Sub-bottom profiling

Future Projections

Sea Level Rise Impact

+15% Rate by 2100

Accommodation space increase

Climate Change Effects

±25% Variability

Precipitation changes

Human Impact

+30% Anthropocene

Land use intensification