TY - JOUR
T1 - Radioactive elements on Mercury's surface from MESSENGER
T2 - Implications for the planet's formation and evolution
AU - Peplowski, Patrick N.
AU - Evans, Larry G.
AU - Hauck, Steven A.
AU - McCoy, Timothy J.
AU - Boynton, William V.
AU - Gillis-Davis, Jeffery J.
AU - Ebel, Denton S.
AU - Goldsten, John O.
AU - Hamara, David K.
AU - Lawrence, David J.
AU - McNutt, Ralph L.
AU - Nittler, Larry R.
AU - Solomon, Sean C.
AU - Rhodes, Edgar A.
AU - Sprague, Ann L.
AU - Starr, Richard D.
AU - Stockstill-Cahill, Karen R.
PY - 2011/9/30
Y1 - 2011/9/30
N2 - The MESSENGER Gamma-Ray Spectrometer measured the average surface abundances of the radioactive elements potassium (K, 1150 ± 220 parts per million), thorium (Th, 220 ± 60 parts per billion), and uranium (U, 90 ± 20 parts per billion) in Mercury's northern hemisphere. The abundance of the moderately volatile element K, relative to Th and U, is inconsistent with physical models for the formation of Mercury requiring extreme heating of the planet or its precursor materials, and supports formation from volatile-containing material comparable to chondritic meteorites. Abundances of K, Th, and U indicate that internal heat production has declined substantially since Mercury's formation, consistent with widespread volcanism shortly after the end of late heavy bombardment 3.8 billion years ago and limited, isolated volcanic activity since.
AB - The MESSENGER Gamma-Ray Spectrometer measured the average surface abundances of the radioactive elements potassium (K, 1150 ± 220 parts per million), thorium (Th, 220 ± 60 parts per billion), and uranium (U, 90 ± 20 parts per billion) in Mercury's northern hemisphere. The abundance of the moderately volatile element K, relative to Th and U, is inconsistent with physical models for the formation of Mercury requiring extreme heating of the planet or its precursor materials, and supports formation from volatile-containing material comparable to chondritic meteorites. Abundances of K, Th, and U indicate that internal heat production has declined substantially since Mercury's formation, consistent with widespread volcanism shortly after the end of late heavy bombardment 3.8 billion years ago and limited, isolated volcanic activity since.
UR - http://www.scopus.com/inward/record.url?scp=80053363602&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=80053363602&partnerID=8YFLogxK
U2 - 10.1126/science.1211576
DO - 10.1126/science.1211576
M3 - Article
C2 - 21960624
AN - SCOPUS:80053363602
SN - 0036-8075
VL - 333
SP - 1850
EP - 1852
JO - Science
JF - Science
IS - 6051
ER -