Evaluation of deep geothermal exploration drillings in the crystalline basement of the Fennoscandian Shield Border Zone in south Sweden

Geothermal Energy

Science – Society – Technology

Table 3 Compilation of thermal conductivity and density measured on cutting samples from FFC-1 and bedrock samples from Dalby quarry on the Romeleåsen Ridge

Sample	Rock type	Thermal conductivity (W/mK)	Density (kg/dm3)	Specific heat capacity (J/kgK)
FFC-1				At 30 °C/100 °C
2771–2774 m^a	Grey–light red-pinkish, quartz-rich gneiss, with < 5% of mafic rocks	3.85 ± 0.05	2.657 ± 0.02	770/877
2873–2875 m^a	Grey and light red gneiss with < 10% mafic rocks	3.95 ± 0.03	2.656 ± 0.02	765/865
2954–2956 m^a	Banded, grey and light red gneiss with < 15% mafic rocks	3.10 ± 0.03	2.694 ± 0.03	770/877
3098–3100 m^a	Amphibolite/metabasite with < 10% amphibolite gneiss and grey–red gneiss	2.54 ± 0.02	2.994 ± 0.03	778/880
3104–3106 m^a	Metabasite/amphibolite gneiss < 5% grey–red gneiss	2.59 ± 0.02	2.969 ± 0.02	776/879
Dalby quarry, outcrop sample^b	Red orthogneiss, fine, foliated	3.55 ± 0.10	2.617 ± 0.05	n/a
-“-^b	-“-, massive, fine, granitic	3.23 ± 0.10	2.622 ± 0.05	n/a
-“-^b	-“-, medium, foliated, biotitic	3.46 ± 0.10	2.619 ± 0.05	n/a
-“-^b	Light red–grey, orthogneiss, fine	3.58 ± 0.10	2.616 ± 0.05	n/a
-“-^b	Red orthogneiss, medium, weakly foliated	3.52 ± 0.10	2.628 ± 0.05	n/a
-“-^b	Amphibolite	2.38 ± 0.10	2.960 ± 0.05	n/a
-“-^b	Amphibolite	2.16 ± 0.10	2.908 ± 0.05	n/a

Specific heat capacity measured at 30 °C and 100 °C on the cuttings from FFC-1 is also presented
^aCuttings sample analysed by Klitzsch and Ahrensmeier (2021)
^bRock sample from outcrop analysed by the Geological Survey of Sweden