Assessing the Geochemical Signatures and Reservoir Quality of Laterite-Cap Sediments in a Tropical Climate for Climate-Resilient Groundwater Resources

Project Abstract

This study investigates the geochemical signatures and reservoir quality of laterite-cap sediments within tropical climates to evaluate their potential for climate-resilient groundwater resources. The research integrates field sampling, laboratory geochemical analyses, and hydrogeological modeling to characterize mineralogical composition, pore-fluid chemistry, weathering intensity, and petrophysical properties that govern groundwater storage and transmissivity. We targeted profile sections within a tropical belt, combining lateritic caps with underlying saprolite and fractured bedrock to determine how altitudinal, lithological, and rainfall gradients influence geochemical evolution and aquifer heterogeneity. Primary data include X-ray diffraction for mineral phases, inductively coupled plasma mass spectrometry for major and trace elements, stable isotope analyses (oxygen, hydrogen, and strontium) to decipher weathering processes and groundwater sources, as well as pore-water extraction to assess salinity, redox state, and organic content. Geophysical logging and aquifer tests (pumping and slug tests) provide estimates of hydraulic conductivity, storativity, and effective porosity, while mercury intrusion porosimetry and micro-CT imaging delineate pore throat distributions and connectivity within laterite-cap materials. The study employs geochemical mass-balance models and reaction-transport simulations to quantify weathering reactants and product fluxes, with emphasis on kaolinite and iron-oxide mineral stability, secondary clays, and cementation effects that modulate porosity and permeability. A multidisciplinary framework is applied to assess reservoir quality under climate-induced stressors such as extreme rainfall variability, prolonged drought, and rising groundwater extraction. Findings are expected to reveal distinct geochemical zonations across the laterite-cap sequence, with enriched oxy-hydroxide minerals driving high cation exchange capacity and sorption potential, while residual porosity and fracturing control transmissivity. Isotopic signatures will help discriminate recharge sources, evapotranspiration effects, and groundwater–surface-water interactions, informing sustainable yield estimates and vulnerability assessments for climate resilience. The research also evaluates the impact of land-use changes, vegetation cover, and hydro-chemical evolution on aquifer recharge efficacy and contaminant mobility. By integrating mineralogy, pore structure, and hydraulic behavior, the study aims to develop a robust framework for predicting groundwater availability in tropical regions with laterite-dominated sediments, providing actionable insights for water resource managers, policymakers, and rural communities dependent on groundwater security. The outcomes will include a proposed typology of laterite-cap aquifers, criteria for selecting sites suitable for managed aquifer recharge, and recommendations for monitoring networks that track geochemical and hydraulic responses to climatic perturbations. Limitations include spatial heterogeneity, access challenges in rugged terrains, and seasonal fluctuations in recharge that may influence data representativeness. Future work will focus on scaling the models to regional basins and integrating climate projections to forecast long-term groundwater resilience.

Project Overview

What This Project Is About

---

A plain-language overview of the topic and what the project investigates.

---

---

The Problem It Addresses

---

What problem or gap this project tackles and why it matters to the field or society.

---

---

Objectives of the Project

---

1. Identify geochemical signatures that indicate groundwater suitability in tropical laterite-cap sediments.
2. Assess how laterite layers affect reservoir quality for groundwater storage and flow.
3. Evaluate temporal changes in rock-water interactions under tropical climate conditions.

---

---

What You Will Do Step by Step

---

Step 1: Review background literature on laterite-cap sediments and groundwater resources.

Step 2: Map study area and collect soil/sediment samples from selected sites.

Step 3: Analyze chemical and mineralogical composition of samples (geochemical tests).

Step 4: Characterize porosity and permeability indicators to gauge reservoir quality.

Step 5: Interpret data to relate geochemistry to groundwater potential and climate factors.

Step 6: Discuss implications for sustainable groundwater management in the tropics.

---

---

Expected Outcome

Clear findings on how laterite-cap sediments influence groundwater availability and quality, with practical recommendations for water resource planning in tropical regions.