TY - JOUR
T1 - 40Ar 39Ar dating of combustion metamorphism ("Mottled Zone", Israel)
AU - Gur, D.
AU - Steinitz, G.
AU - Kolodny, Y.
AU - Starinsky, A.
AU - McWilliams, M.
PY - 1995/5/30
Y1 - 1995/5/30
N2 - Tertiary surface combustion of Cretaceous bituminous sediments in Israel produced high-T, low-P metamorphic assemblages, which were dated by conventional KAr and 40Ar 39Ar techniques. Meaningful ages were obtained from samples of high metamorphic grade and K content higher than 0.8%, containing sanidine, anorthite, gehlenite and zeolites. In these minerals the KAr system has been reset, and equilibrated with atmospheric Ar, yielding a mean age of 3 ± 1 Ma. 40Ar 39Ar plateau and isochron ages for four whole-rock samples range between 2.3 and 4.0 Ma. One gehlenite rock yielded an 40Ar 39Ar age of 16 ± 0.2 Ma (1σ). These results indicate a major combustion metamorphic event around 3 Ma, probably preceded by an event around 16 Ma. The early event took place upon initial exposure of the protolith in the Miocene, whereas the second followed the removal of Neogene sediments and re-exposure of the bituminous rocks.
AB - Tertiary surface combustion of Cretaceous bituminous sediments in Israel produced high-T, low-P metamorphic assemblages, which were dated by conventional KAr and 40Ar 39Ar techniques. Meaningful ages were obtained from samples of high metamorphic grade and K content higher than 0.8%, containing sanidine, anorthite, gehlenite and zeolites. In these minerals the KAr system has been reset, and equilibrated with atmospheric Ar, yielding a mean age of 3 ± 1 Ma. 40Ar 39Ar plateau and isochron ages for four whole-rock samples range between 2.3 and 4.0 Ma. One gehlenite rock yielded an 40Ar 39Ar age of 16 ± 0.2 Ma (1σ). These results indicate a major combustion metamorphic event around 3 Ma, probably preceded by an event around 16 Ma. The early event took place upon initial exposure of the protolith in the Miocene, whereas the second followed the removal of Neogene sediments and re-exposure of the bituminous rocks.
UR - http://www.scopus.com/inward/record.url?scp=0028848760&partnerID=8YFLogxK
U2 - 10.1016/0009-2541(95)00034-J
DO - 10.1016/0009-2541(95)00034-J
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AN - SCOPUS:0028848760
SN - 0009-2541
VL - 122
SP - 171
EP - 184
JO - Chemical Geology
JF - Chemical Geology
IS - 1-4
ER -