Residential Buildings Procurement with Labour only Method: Performance Evaluation among Federal Income Earners in Akwa Ibom State

Abstract

Nahuta Clays occurs within the Rop Complex, Jos Plateau, north central Nigeria. The present study focuses on the mineralogical compositions of Nahuta clay with the aim of ascertaining the protoliths and process of clay formation.

The clay samples were studied geochemically using X-Ray Diffraction analyses. The peaks of XRD analyses of representative clay samples indicate four groups of clay minerals and they include:

Serpentinite-Kaolin group (kaolinite, dickite and halloysite); Pyrophyllite-Talc group (talc and pyrophyllite); Mica group (phlogopite, hydrobiotite and illite) and Palygorskite-Sepiolite group (sepiolite).

Based on the mineralogical compositions of Nahuta clay, the other non-clay minerals identified are: quartz, osumilite, tobermorite, albite and hematite.

The presence of kaolinite, illite, quartz and albite indicate felsic rocks as the predominant protoliths of Nahuta clay. Osumilite occurs as grains in volcanic rocks while tobermorite occurs as hydrothermal product in basaltic rocks.

This is suggestive that part of the protoliths of Nahuta clay was derived from hydrothermal alteration of basaltic rocks.

The presence of dickite, osumilite and tobermorite further attest to hydrothermal alteration of the protoliths because dickite, osumilite and tobermorite are restricted to hydrothermal occurrences.

This is indicative that the process of formation of Nahuta clay is through hydrothermal alteration and/or weathering of granitic host rocks with contributions from volcanic rocks.

Introduction

Background Of Study

Nahuta clay occurs in the western part of the Rop Complex, Jos Plateau, north central Nigeria (Fig. 1). The Rop Complex is a roughly triangular area of 360km² of which 105 km² are underlain by the Younger Granite suites.

The Basement Complex rocks are the oldest rocks and they underlie the Rop Complex (Macleod, Turner, & Wright, 1971).

Nahuta area is located within Latitudes 9^o29^l to 9^o 32^l N and Longitudes 8^o51^l to 8^o53^lE on the North East of Topographical Sheet 189 (Kurra).

This area is bounded to the North by Gana Rop and to the west by Rarin Sho village. Most clay minerals form where rocks are in contact with water, air or steam.

These situations include weathering boulders on a hillside, deeply buried sediments containing pore water, and rocks in contact with hydrothermal fluids.

The origin of clays and clay minerals is governed principally by protore rocks, climate, relief and time (Blum & Stillings, 1995; Buggle, Glaser, Hambach, Gerasimenko, & Markovič, 2011).

The primary minerals are replaced by the secondary minerals when there is a change in the prevailing conditions subjected to the rock.

Hydrothermal alteration is a chemical replacement of the original minerals in a rock by new minerals via interaction with hydrothermal fluids.

The hydrothermal fluids cause hydrothermal alteration of rocks by passing hot water fluids through the rocks and changing their composition by adding, removing or redistributing components (Eberl, 1984; Konta, 1995).

In geothermal environments, primary minerals usually tend to alter to hydrothermal alteration minerals that are either stable or at least metastable in these environments.

References

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