Reply to discussion on ‘Spectral analysis of aeromagnetic data for geothermal energy investigation of Ikogosi Warm Spring - Ekiti State, southwestern Nigeria’

Ema Michael Abraham,Kehinde Ayofe Murana,Kolawole Muideen Lawal,Amobi Chigozie Ekwe,Aminu Ahmed Lawal,Owens Alile

doi:10.1186/s40517-014-0018-9

Ema Michael Abraham, Kehinde Ayofe Murana + Show 4 more

Open Access

https://doi.org/10.1186/s40517-014-0018-9

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Abstract

In reply to Geothermal Energy 2:11 comments about possible errors in our recent paper Geothermal Energy 2:6, 1-21 with title ‘Spectral analysis of aeromagnetic data for geothermal energy investigation of Ikogosi Warm Spring - Ekiti State, southwestern Nigeria’, we show that there are no errors in the published paper. Our choice of 55 × 55 km block dimension slide across the magnetic anomaly map is consistent with the derived Curie point depths. This choice was adopted because of complexity of the geology in the area and the need to sample more data points while preserving the spectral peak. All depth estimates were carefully and thoroughly performed and assessed using tectonic framework, geological and geophysical evidence, heat flow, seismicity, and other independent information.

Highlights

The method used for basal or Curie point depth (CPD) calculations is very subjective, needs great caution, and has to be constrained by independent information for a particular region
We scrutinize the assertion that given our data window of 55 × 55 km, the computed CPD was marked with errors
Aboud et al (2011) used windows of size 100 × 100 km to map the Curie depth isotherm surface for Sinai Peninsula, Egypt based on the spectral analysis of ground magnetic data

Summary

Introduction

The method used for basal or Curie point depth (CPD) calculations is very subjective, needs great caution, and has to be constrained by independent information for a particular region. One obtains a linear slope approximately twice the maximum depths to the various magnetic sources (Rabeh et al 2008; Trifonova et al 2009; Bansal et al 2011; Abraham et al 2014). The depths obtained for the bottom of the magnetized crust are assumed to correspond to the CPD where the magnetic layer loses its magnetization (Aboud et al 2011; Abraham et al 2014). The results may not delineate local shallow or deep CPD anomaly (Aboud et al 2011; Abraham et al 2014). In this debate, we scrutinize the assertion that given our data window of 55 × 55 km, the computed CPD was marked with errors. We shall prove that re-computing our depths is not necessary as our assumed CPD is adequate for the window and method chosen

Discussion

Conclusion