Claritas rise, Mars: Pre-Tharsis magmatism?

Ancient heat flow and crustal thickness at Warrego rise, Thaumasia highlands, Mars: Implications for a stratified crust

“…These estimations were performed without taking into account the presence of radioactive heat sources in the crust. However, the use of crustal heat sources in this kind of calculation increases the obtained surface heat flows and potentially places constraints on the thickness and differentiation state of the crust (Ruiz et al, 2006a(Ruiz et al, ,b, 2008Dohm et al, 2009), which is the aim of this paper. Thus, we use estimated faulting depths beneath the western and eastern scarps in order to calculate heat flows (valid for the time when the faults were formed) by taking into account crustal heat sources, following the procedure described in Ruiz et al (2008).…”

“…Calculations of ancient heat flows on Mars based on geological and/or geophysical proxies (e.g., the depth to the brittle-ductile transition or the effective elastic thickness of the lithosphere) have been used, along with information of crustal radioactive heating rates, to obtain constraints on both the thickness and the geochemical stratification, of the martian crust (Ruiz et al, 2006a(Ruiz et al, ,b, 2008Dohm et al, 2009). For example, Ruiz et al (2008) found a crustal thickness of 43-74 km for the Amenthes region (at least for the Late Noachian/Early Hesperian time, the time when the large-scale topography and tectonic features used as indicators were formed), by simultaneously considering the brittle-ductile transition depth, the effective elastic thickness, and a reasonable range of values for crustal density, strain rate, and radioactive heating rate.…”

“…The effective elastic thickness can be used in the same way if this thickness is sufficiently low to preclude lithosphere mantle contributions to the total strength of the lithosphere (Dohm et al, 2009). In this work, we analyze the Warrego rise region, a prominent part of the Thaumasia highlands mountain range on Mars (Fig.…”

The thermal evolution of Mars as constrained by paleo-heat flows

“…Previous works estimated surface heat flows for diverse regions and epochs of Mars from the effective elastic thickness of the lith osphere (Solomon and Head, 1990;Anderson and Grimm, 1998;Zuber et al, 2000;Nimmo, 2002;Kiefer, 2004;McGovern et al, 2002McGovern et al, , 2004Grott et aI., 2005;Ruiz et aI., 2006aRuiz et aI., ,b, 2008Ruiz et aI., , 2010Kronberg et al, 2007;Ruiz, 2009;Dohm et al, 2009a;Ritzer and Hauck, 2009) or from the depth to the brittle-ductile transition (BDT) beneath large thrust faults ( Schultz and Watters, 2001;Grott et al, 2007;Ruiz et al, 2008Ruiz et al, , 2009; such heat flow estimates cor respond to the time when the lithosphere was loaded or faulted.…”

The present-day thermal state of Mars

“…Knowledge ofthe surface heat flow is very important for understanding the thermal and geologic evolution of a planetary body. There are not direct measurements for Mars, but heat flows have been deduced for diverse martian regions from the effective elastic thickness of the lithosphere (Solomon and Head, 1990;Anderson and Grimm, 1998;Zuber et al, 2000;Nimmo, 2002;Kiefer, 2004;McGovern et al, 2002McGovern et al, , 2004Grott et al, 2005;Ruiz et al, 2006Ruiz et al, , 2008Kronberg et al, 2007;Ruiz, 2009;Dohm et al, 2009a;Ritzer and Hauck, 2009 ) or from the depth to the brittle-ductile transition beneath large thrust faults (Schultz and Watters, 2001;Grott et al, 2007;Ruiz et al, 2008Ruiz et al, , 2009. So deduced heat flows are valid for the time when the lithosphere was loaded or faulted, permitting us to delinea te, in a tirst approximation, the thermal evolution Given the lack of large scale tectonic activity at the present time, the possibility of using effective elastic thicknesses for estimating the present-day thermal state of this planet seems restricted to the polar regions, where loading by ice caps is a recent phenomenon, estimated to be a few million years old (Laskar et al, 2002;Phillips et al, 2008 ).…”