Global map of lithosphere thermal thickness on a 1 deg x 1 deg grid - digitally available

TY - ABST

T1 - Global map of lithosphere thermal thickness on a 1 deg x 1 deg grid - digitally available

AU - Artemieva, Irina

PY - 2014/4

Y1 - 2014/4

N2 - This presentation reports a 1 deg 1 deg global thermal model for the continental lithosphere (TC1). The modelis digitally available from the author’s web-site: www.lithosphere.info.Geotherms for continental terranes of different ages (early Archean to present) are constrained by reliabledata on borehole heat flow measurements (Artemieva and Mooney, 2001), checked with the original publicationsfor data quality, and corrected for paleo-temperature effects where needed. These data are supplemented bycratonic geotherms based on xenolith data.Since heat flow measurements cover not more than half of the continents, the remaining areas (ca. 60% ofthe continents) are filled by the statistical numbers derived from the thermal model constrained by boreholedata. Continental geotherms are statistically analyzed as a function of age and are used to estimate lithospherictemperatures in continental regions with no or low quality heat flow data. This analysis requires knowledge oflithosphere age globally.A compilation of tectono-thermal ages of lithospheric terranes on a 1 deg 1 deg grid forms the basis forthe statistical analysis. It shows that, statistically, lithospheric thermal thickness z (in km) depends on tectonothermalage t (in Ma) as: z=0.04t+93.6. This relationship formed the basis for a global thermal model of thecontinental lithosphere (TC1). Statistical analysis of continental geotherms also reveals that this relationship holdsfor the Archean cratons in general, but not in detail. Particularly, thick (more than 250 km) lithosphere is restrictedsolely to young Archean terranes (3.0–2.6 Ga), while in old Archean cratons (3.6–3.0 Ga) lithospheric roots donot extend deeper than 200–220 km.The TC1 model is presented by a set of maps, which show significant thermal heterogeneity within continentalupper mantle. The strongest lateral temperature variations (as large as 800 deg C) are typical of the shallowmantle (depth less than 100 km). A map of the depth to a 600 deg C isotherm in continental upper mantle ispresented as a proxy to the elastic thickness of the cratonic lithosphere, in which flexural rigidity is dominated byolivine rheology of the mantle. The TC1 model of the lithosphere thickness is used to calculate the growth andpreservation rates of the lithosphere since the Archean.

AB - This presentation reports a 1 deg 1 deg global thermal model for the continental lithosphere (TC1). The modelis digitally available from the author’s web-site: www.lithosphere.info.Geotherms for continental terranes of different ages (early Archean to present) are constrained by reliabledata on borehole heat flow measurements (Artemieva and Mooney, 2001), checked with the original publicationsfor data quality, and corrected for paleo-temperature effects where needed. These data are supplemented bycratonic geotherms based on xenolith data.Since heat flow measurements cover not more than half of the continents, the remaining areas (ca. 60% ofthe continents) are filled by the statistical numbers derived from the thermal model constrained by boreholedata. Continental geotherms are statistically analyzed as a function of age and are used to estimate lithospherictemperatures in continental regions with no or low quality heat flow data. This analysis requires knowledge oflithosphere age globally.A compilation of tectono-thermal ages of lithospheric terranes on a 1 deg 1 deg grid forms the basis forthe statistical analysis. It shows that, statistically, lithospheric thermal thickness z (in km) depends on tectonothermalage t (in Ma) as: z=0.04t+93.6. This relationship formed the basis for a global thermal model of thecontinental lithosphere (TC1). Statistical analysis of continental geotherms also reveals that this relationship holdsfor the Archean cratons in general, but not in detail. Particularly, thick (more than 250 km) lithosphere is restrictedsolely to young Archean terranes (3.0–2.6 Ga), while in old Archean cratons (3.6–3.0 Ga) lithospheric roots donot extend deeper than 200–220 km.The TC1 model is presented by a set of maps, which show significant thermal heterogeneity within continentalupper mantle. The strongest lateral temperature variations (as large as 800 deg C) are typical of the shallowmantle (depth less than 100 km). A map of the depth to a 600 deg C isotherm in continental upper mantle ispresented as a proxy to the elastic thickness of the cratonic lithosphere, in which flexural rigidity is dominated byolivine rheology of the mantle. The TC1 model of the lithosphere thickness is used to calculate the growth andpreservation rates of the lithosphere since the Archean.

M3 - Conference abstract in journal

SN - 1607-7962

VL - 16

JO - Geophysical Research Abstracts

JF - Geophysical Research Abstracts

M1 - 7565

T2 - EGU General Assembly 2014

Y2 - 27 April 2014 through 2 May 2014

ER -