Taking the pulse of Mars via dating of a plume-fed volcano

Abstract

Mars hosts the solar system’s largest volcanoes. Although their size and impact crater density indicate continued activity over billions of years, their formation rates are poorly understood. Here we quantify the growth rate of a Martian volcano by 40Ar/39Ar and cosmogenic exposure dating of six nakhlites, meteorites that were ejected from Mars by a single impact event at 10.7 ± 0.8 Ma (2σ). We find that the nakhlites sample a layered volcanic sequence with at least four discrete eruptive events spanning 93 ± 12 Ma (1416 ± 7 Ma to 1322 ± 10 Ma (2σ)). A non-radiogenic trapped 40Ar/36Ar value of 1511 ± 74 (2σ) provides a precise and robust constraint for the mid-Amazonian Martian atmosphere. Our data show that the nakhlite-source volcano grew at a rate of ca. 0.4–0.7 m Ma−1—three orders of magnitude slower than comparable volcanoes on Earth, and necessitating that Mars was far more volcanically active earlier in its history.

Caleta el Cobre 022 Martian meteorite: Increasing nakhlite diversity

“…Nakhlites all share broadly similar textures, whole-rock compositions, and mineralogy. In addition, they all present a crystallization age within the same range from 1.26 to 1.42 Ga, consistent over four different dating techniques 87 Rb/ 86 Sr, 147 Sm/ 144 Nd, 39 Ar/ 40 Ar, and 176 Lu/ 176 Hf (from data compilation of Nyquist et al 2001;Shih et al 2010;Korochantseva et al 2011;Cohen et al 2017;Udry and Day 2018). Lastly, cosmogenic isotopes yield an exposure age of 9-13 Ma, which indicates a single ejection event, strengthening their genetic relationship (Nyquist et al 2001;Herzog and Caffee 2013;Wieler et al 2016;Cohen et al 2017).…”

“…Caleta el Cobre 022's crystallization age of 1.215 AE 0.067 Ga is close to other nakhlites, even though it is slightly younger than Nakhla (Treiman 2005;Cohen et al 2017;Udry and Day 2018). The 2002, and Jambon et al (2016).…”

“…Based on geochemistry and petrography, Balta et al (2017) proposed another model with one body chamber and two separated lobes. Cohen et al (2017) proposed a model of multiple flows using geochronological evidences supporting a layered volcanic sequence with at least four discrete eruptive events. Recently, Udry and Day (2018) proposed in a comprehensive study that nakhlites originated from at least six different lava flows or sills, distributed around one or several volcano vents.…”

Apatite from NWA 10153 and NWA 10645—The Key to Deciphering Magmatic and Fluid Evolution History in Nakhlites

“…The diffraction pattern of phosphate in meteorite NWA 10153 yielded values of 34.4° and 55.6° between adjacent lattice planes (Figure 6c,d). The observed angles correspond to the calculated (0001)/(11-21) angle of 34.27° and a (11-21)/ (11)(12)(13)(14)(15)(16)(17)(18)(19)(20) angle of 55.37°. The values of the angles between adjacent lattice planes in the diffraction pattern of phosphate in meteorite NWA 10645 were approximately 60°, which are consistent with the calculated angle of 30° in the hexagonal system (Figure 7g).…”

“…The age of secondary alterations at low temperatures was proposed to be 633 ± 23 Ma ago [70], whereas the high-temperature alteration possibly occurred shortly after the nakhlites emplacement between 1.26 and 1.42 Ga [14][15][16][17][18]. Considering the presented data, alterations that were considered low-temperature actually occurred at much higher temperatures and much earlier than the proposed aqueous alteration [70].…”