In Situ Radiometric and Exposure Age Dating of the Martian Surface
Authors: Farley K. A. , Malespin C. , Mahaffy P. , Grotzinger J. P. , Vasconcelos P. M. , Milliken R. E. , Malin M. , Edgett K. S. , Pavlov A. A. , Hurowitz J. A. , Grant J. A. , Miller H. B. , Arvidson R. , Beegle L. , Calef F. , Conrad P. G. , Dietrich W. E. , Eigenbrode J. , Gellert R. , Gupta S. , Hamilton V. , Hassler D. M. , Lewis K.W. , McLennan S. M. , Ming D. , Navarro-González R. , Schwenzer S. P. , Steele A. , Stolper E. M. , Sumner D. Y. , Vaniman D. , Vasavada A. , Williford K. , Wimmer-Schweingruber R. F. ,   the MSL Science Team, Blake David F. , Bristow Thomas , DesMarais David , Edwards Laurence , Haberle Robert , Hoehler Tori , Hollingsworth Jeff , Kahre Melinda , Keely Leslie , McKay Christopher , Wilhelm Mary Beth , Bleacher Lora , Brinckerhoff William , Choi David , Dworkin Jason P. , Floyd Melissa , Freissinet Caroline , Garvin James , Glavin Daniel , Harpold Daniel , Martin David K. , McAdam Amy , Raaen Eric , Smith Michael D. , Stern Jennifer , Tan Florence , Trainer Melissa , Meyer Michael , Posner Arik , Voytek Mary , Anderson Robert C. , Aubrey Andrew , Behar Alberto , Blaney Diana , Brinza David , Christensen Lance , Crisp Joy A. , DeFlores Lauren , Feldman Jason , Feldman Sabrina , Flesch Gregory , Hurowitz Joel , Jun Insoo , Keymeulen Didier , Maki Justin , Mischna Michael , Morookian John Michael , Parker Timothy , Pavri Betina , Schoppers Marcel , Sengstacken Aaron , Simmonds John J. , Spanovich Nicole , Juarez Manuel de la Torre , Webster Christopher R. , Yen Albert , Archer Paul Douglas , Cucinotta Francis , Jones John H. , Morris Richard V. , Niles Paul , Rampe Elizabeth , Nolan Thomas , Fisk Martin , Radziemski Leon , Barraclough Bruce , Bender Steve , Berman Daniel , Dobrea Eldar Noe , Tokar Robert , Williams Rebecca M. E. , Yingst Aileen , Leshin Laurie , Cleghorn Timothy , Huntress Wesley , Manhès Gérard , Hudgins Judy , Olson Timothy , Stewart Noel , Sarrazin Philippe , Vicenzi Edward , Wilson Sharon A. , Bullock Mark , Ehresmann Bent , Peterson Joseph , Rafkin Scot , Zeitlin Cary , Fedosov Fedor , Golovin Dmitry , Karpushkina Natalya , Kozyrev Alexander , Litvak Maxim , Malakhov Alexey , Mitrofanov Igor , Mokrousov Maxim , Nikiforov Sergey , Prokhorov Vasily , Sanin Anton , Tretyakov Vladislav , Varenikov Alexey , Vostrukhin Andrey , Kuzmin Ruslan , Clark Benton , Wolff Michael , Botta Oliver , Drake Darrell , Bean Keri , Lemmon Mark , Anderson Ryan B. , Herkenhoff Kenneth , Lee Ella Mae , Sucharski Robert , Hernández Miguel Ángel de Pablo , Ávalos Juan José Blanco , Ramos Miguel , Kim Myung-Hee , Plante Ianik , Muller Jan-Peter , Ewing Ryan , Boynton William , Downs Robert , Fitzgibbon Mike , Harshman Karl , Morrison Shaunna , Kortmann Onno , Palucis Marisa , Williams Amy , Lugmair Günter , Wilson Michael A. , Rubin David , Jakosky Bruce , Balic-Zunic Tonci , Frydenvang Jens , Jensen Jaqueline Kløvgaard , Kinch Kjartan , Koefoed Asmus , Madsen Morten Bo , Stipp Susan Louise Svane , Boyd Nick , Campbell John L. , Perrett Glynis , Pradler Irina , VanBommel Scott , Jacob Samantha , Owen Tobias , Rowland Scott , Savijärvi Hannu , Boehm Eckart , Böttcher Stephan , Burmeister Sönke , Guo Jingnan , Köhler Jan , García César Martín , Mueller-Mellin Reinhold , Bridges John C. , McConnochie Timothy , Benna Mehdi , Franz Heather , Bower Hannah , Brunner Anna , Blau Hannah , Boucher Thomas , Carmosino Marco , Atreya Sushil , Elliott Harvey , Halleaux Douglas , Rennó Nilton , Wong Michael , Pepin Robert , Elliott Beverley , Spray John , Thompson Lucy , Gordon Suzanne , Newsom Horton , Ollila Ann , Williams Joshua , Bentz Jennifer , Nealson Kenneth , Popa Radu , Kah Linda C. , Moersch Jeffrey , Tate Christopher , Day Mackenzie , Kocurek Gary , Hallet Bernard , Sletten Ronald , Francis Raymond , McCullough Emily , Cloutis Ed , ten Kate Inge Loes , Kuzmin Ruslan , Fraeman Abigail , Scholes Daniel , Slavney Susan , Stein Thomas , Ward Jennifer , Berger Jeffrey , Moores John E. 
Published: December 2013

We determined radiogenic and cosmogenic noble gases in a mudstone on the floor of Gale Crater. A K-Ar age of 4.21 ± 0.35 billion years represents a mixture of detrital and authigenic components and confirms the expected antiquity of rocks comprising the crater rim. Cosmic-ray–produced
3
He,
21
Ne, and
36
Ar yield concordant surface exposure ages of 78 ± 30 million years. Surface exposure occurred mainly in the present geomorphic setting rather than during primary erosion and transport. Our observations are consistent with mudstone deposition shortly after the Gale impact or possibly in a later event of rapid erosion and deposition. The mudstone remained buried until recent exposure by wind-driven scarp retreat. Sedimentary rocks exposed by this mechanism may thus offer the best potential for organic biomarker preservation against destruction by cosmic radiation.