Editorial to the third issue of “International Journal of Terrestrial Heat Flow and Applications”

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International Journal of Terrestrial Heat Flow and Applied Geothermics
VOL. 3, NO. 1 (2020)
ISSN: 2595-4180 http://ijthfa.com/
III
Editorial to the third issue of “International Journal of Terrestrial Heat
Flow and Applied Geothermics”
Valiya M. Hamza1 and Jorge L.S. Gomes 2
1 Department of Geophysics, National Observatory, Rio de Janeiro, Brazil.
2 Institute of Science Engineering and Technology, Federal University of the Jequitinhonha and Mucuri Valleys, Teófilo
Otoni, Brazil.
The third issue of the International Journal of Terrestrial Heat Flow and Applied Geothermics – IJTHFA has been useful as
a step further in bringing together several important works on geothermal research. It is indication that IJTHFA is a closer to
being recognized as the most convenient and useful forum for dissemination of research results and information within the IHFC
community.
The papers appearing in this third issue are focused on improving our understanding of heat flow variations in parts of the
Earth, vital for promoting international geothermal research. These include Antarctic continent, area of Poland, Norte basin in
Uruguay, Absheron Peninsula in Azerbaijan and Beiras region of Portugal. Also discussed is nature of subsurface thermal signals
generated by recent climate changes in Ajameti, Georgia.
This issue also brings out an updated heat flow data set for Brazil, which has been organized following the traditional scheme
adopted by IHFC for global compilations. However, a multiprong referencing system has been introduced that allow citations of
recent works on improvements in data acquisition, progress obtained in analysis and interpretation techniques and advances in
instrumental techniques.
With publication of the third issue of we expect to inform scholars of recent advances, evolving trends and new ideas being
put forward in our own particular areas of specialty, both for enlivened discussions and for promoting research by next
generations of experts.
The academic world is mostly driven by cross-disciplinary visions and models, but the importance of intra-disciplinary
approach cannot be underestimated. The approach embraced in IJTHFA is expected to provide a broadened and modern
perspective of international geothermal research.
The organizers of the International Journal of Terrestrial Heat Flow and Applied Geothermics (IJTHFA) received seven
manuscripts, which after due review process were accepted for publication. Given below is a brief overview of the accepted
contributions.
Overview of Accepted Contributions
Suzi Guimarães, Fabio Vieira and Valiya Hamza
presents a reappraisal of terrestrial heat flow variations in the
Antarctic continent, based on recent advances in data analysis
and regional assessments. The data considered include those
reported at the website of IHFC and 78 additional sites where
measurements have been made using a variety of techniques.
These include values based on the Method of Magmatic Heat
Budget (MHB) for 41 localities in areas of recent volcanic
activity and estimates that rely on basal temperatures of
glaciers in 372 localities that are known to host subglacial
lakes. The total number of data assembled is 491, which has
been useful in deriving a 10ox10o grid system of homogenized
heat flow values and in deriving a new heat flow map of the
Antarctic continent. The results reveal that the Antarctic
Peninsula and western segment of the Antarctic continent has
distinctly high heat flow relative to the eastern regions. The
general pattern of differences in heat flow between eastern and
western of Antarctic continent is in striking agreement with
results based on seismic velocities.
Jacek Majorowicz and Marek Grad discuss differences
between heat flow Maps of Poland in the light of deep thermo-
seismic and tectonic age constraints. To begin with they note
that the area of Poland is a place of contacts between three
continental scale tectonic units. The Trans-European suture
zone between east European craton and the west European
platform is a deep-seated discontinuity reaching at least down
to a depth of about 200 km. The conjunction of these
continental scale tectonic units is reflected in the complex
tectonic structure of this area. This area is also associated with
pronounced gravity, magnetic and heat flow anomalies.
Significant differences in heat flow of 20 to 30 mWm-2 exist
between heat flow maps of Poland published in recent works.
Examples are differences in heat flow based on thermal
conductivity models using well log interpreted mineral and
porosity content and assigned world averages of rock and fluid
thermal conductivity versus ones based on averaging thermal
conductivity measured using borehole cores only. The
significance of such differences in heat flow between both
methods used are discussed in the context of their relationship
with tectonic age. Also considered are resulting thermal depth
differences of lithosphere – asthenosphere boundary (LAB) vs
seismological constraint. They conclude that higher heat flow
estimates reaching more than 100 mWm-2, based on
conductivity values derived from well-logs, are found to be
quite improbable.
Ethel Morales, Agostina Pedro and Ricardo De León
discuss progress obtained in a partial update of geothermal
gradient and terrestrial heat flow values for the Norte Basin
(Uruguay). It is based on results of temperature measurements
carried out in deep water wells. Most of the wells considered

Hamza and Gomes: Editorial for Third Issue of IJTHFA.
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International Journal of Terrestrial Heat Flow and Applied Geothermics. VOL. 3, NO. 1 (2020).
in their work have intersected the southern part of the Guarani
Aquifer System, at depths varying from 200 to 1500m. The
results indicate that temperature gradients fall in the range of
15 to 45oC/km and the thermal conductivity of basalts have a
mean value of 2.2W/m/K. Analysis of temperature
distributions indicate that heat transfer takes place not only by
conduction but also by upflow of groundwater with velocities
in the range of 10-9 to 10-8 m/s. The representative mean heat
flow values fall in the range of 30 to 85mW/m2. Maps of
spatial distributions of geothermal gradients and heat flow
values have been considered as indicative of the possible
existence of an anomalous geothermal zone in the central-
northwestern part of the Norte Basin. There are indications
that this anomalous geothermal zone extends also to the
eastern parts of adjacent regions in Argentina. There are
indications of relatively low heat flow in the adjacent regions
of Norte Basin.
Aygun Mamadova discuss Geothermal field of the
Pliocene complex in the Absheron peninsula, Azerbaijan on
the basis of temperature distributions in over 50 deep wells.
Data analysis include variations in geothermal gradient and
heat flow within complexes of Absheron formation of upper
Pliocene in age. Geothermal gradients are in the range of 17 to
25oC/km. The heat flow values fall in the range of 50 to
80mW/m2. Estimates have been made of geothermal energy
resources up to depths of 6000 meters. The main productive
strata of hot fluids are of middle Pliocene in age. The results
have allowed identification of geothermal resources with
temperature above the 20°C and at depths less than 110-180
meters. Model simulations point to perspectives for
widespread utilization of geothermal energy in the Absheron
peninsula.
Maria Rosa Duque discuss results of numerical
simulations of heat flow in the Beiras Region, Mainland
Portugal. The procedure adopted is based on results of deep
crustal geophysical surveys and consider that the heat flow
measured at the surface results from the addition of heat
generated in the crust by radioactive sources and that coming
from the mantle. Radioactive heat sources in the region are
heterogeneous and heat flow values at the surface depends on
the thickness of upper crustal layers. The models employed
make use of data derived from geophysical surveys of Moho
depths and detailed results related to seismic velocity
distribution in the crust. In addition, results of radiometric
surveys are employed in deriving heat production values for
upper layers of the crust. The resulting heat flow density
values are similar to those found for areas with similar tectonic
characteristics in Southern Portugal.
Günter Buntebarth, Tamar Jimsheladze, Genadi
Kobzev, George Melikadze discuss daily temperature
variations at the subsurface combined with water level
records, in Ajameti/Georgia. In this work, daily variations are
analyzed for time periods of February/March 2018 and April
2018. Their frequency spectra demonstrate that the diurnal and
semi-diurnal variations are generated by earth tides. The
enhanced amplitude of the diurnal period at depth of 100 m
coincides with the growth phase of vegetation. Frequent
rainfall did not affect the temperature at 100 m or deeper but
raises the water level. Daily surface temperature variations
relate to the temperature variation at the subsurface during the
growth phase of vegetation in April and down to 175 m. No
relation is detected in records obtained during February/March
and at 250 m in both cases. Temperature fluctuations are
translated to vertical water movements in the borehole after
removal of the effects of temperature gradient. The estimated
water flow yields an amplitude of 0.1 m at 250 m but increases
continuously to 0.16 m at 100 m. However, the water level
variation reaches only 0.03 m at the surface. It is likely that the
free surface of the water level has an additional degree of
freedom which causes the lower magnitude of fluctuation.
Valiya Hamza, Fabio Vieira, Jorge Gomes, Suze
Guimaraes, Carlos Alexandrino and Antônio Gomes
presents an updated heat-flow database for Brazil is presented
providing details of measurements carried out at 406 sites. It
has been organized as per the system proposed by IHFC. The
data sets refer to results obtained using methods referred to as
interval temperature logs (ITL), underground mines (UMM),
bottom-hole temperatures (BHT), stable bottom temperatures
(SBT) and pumping wells (AQT). Additional information on
data sources are provided in a separate table. A new heat flow
map of Brazil has been derived based on the updated data set.
Complementary information on references and year of
publication are provided in separate tables.
In addition, a multiprong referencing system has been
employed in citing references. The indexing scheme adopted
for this purpose provides information on not only the primary
work on heat flow determination but also later improvements
in measurements of the main parameters (temperature
gradients, thermal conductivity and radiogenic heat
production) as well as techniques employed in data analysis.
Concluding Remarks
The editors of this journal are indebted to members of the
International Geothermal Community who contributed to
successful publication of this issue.
Special thanks are due to those who took part in reviewing
the manuscripts. The list of distinguished reviewers for this
issue includes Antonio Correa (University of Evora, Portugal),
Jan Safanda (Institute of Geophysics, Academy of Sciences,
Czech Republic), Ladislaus Rybach (Earth Science Institute,
Switzerland), Maria Rosa Duque (University of Evora,
Portugal), Massimo Verdoya (Department of Earth,
Environment and Life Sciences, University of Genova, Italy),
Sven Fuchs (Thermal Petrophysics Lab, Geo Forschung
Zentrum, Potsdam, Germany), Shaopeng Huang (Xi'an
Jiaotong University, China and University of Michigan, USA)
and Vladimir Cermak (Institute of Geophysics, Academy of
Sciences, Czech Republic).
We also thank the editorial staff of IJTHFA in contributing
with suggestions for improving the grammatical structure and
style of writing in the original versions of most manuscripts.
These have been most useful for producing this volume.