Punctuated Evolution of a Large Epithermal Province: The Hauraki Goldfield, New Zealand

In the northern province of the goldfield, adularia from Paritu yields a single 40Ar/39Ar plateau date of 16.32 +/- 0.13 Ma, and adularia from Opitonui yields a preferred 40Ar/39Ar age of 13.15 +/- 0.03 Ma. Two Re-Os dates of molybdenite from porphyry-style mineralization at Ohio Creek overlap within error and yield dates of 11.87 +/- 0.06 and 11.97 +/- 0.08 Ma; geologic relationships suggest that this is the likely age of mineralization in the nearby Thames epithermal deposits. In the eastern province, adularia from the Ohui deposit gives a preferred 40Ar/39Ar age of 8.29 +/- 0.25 Ma, adularia from the Broken Hills deposit gives a preferred 40Ar/39Ar age of 7.12 +/- 0.02 Ma, and adularia from the Wharekirauponga prospect yields a preferred Ar-10/39Ar age of 6.32 +/- 0.12 Ma. In the southern province, adularia from quartz veins at the Maratoto deposit provide a preferred 40Ar/39Ar age of 6.41 +/- 0.04 Ma, and adularia from a quartz vein at the Sovereign deposit yields a preferred 40Ar/39Ar age of 6.70 +/- 0.16 Ma. Two dates from vein adularia at the world-class Martha deposit overlap within error, and we interpret a preferred age for the deposit of 6.16 +/- 0.06 Ma. Two samples of molybdenite from veins in the Martha deposit yield discrete Re-Os dates of 6.37 +/- 0.03 and 6.51 +/- 0.03 Ma. Adularia from one quartz vein from the Favona deposit yields a 40Ar/39Ar date of 6.05 +/- 0.04 Ma. Host rock and vein adularia from the Karangahake deposit yield 40Ar/39Ar plateau dates that range from 6.90 +/- 0.20 to 5.71 +/- 0.13 Ma, which may reflect more than one stage of mineralization or protracted fluid flow. Adularia from veins at the Waiorongomai deposit yields,a preferred 40Ar/39Ar age of 5.71. +/- 0.03 Ma, and adularia from a vein at the Eliza deposit yields a preferred age of 4.47 +/- 0.06 Ma. The southernmost deposit in the Hauraki goldfield, Muirs Reef, has adularia in quartz veins that yield 40Ar/39Ar plateaus dates of 2.12 +/- 0.11 to 1.78 +/- 0.16 Ma. In the northern province of the goldfield, adularia from Paritu yields a single 40Ar/39Ar plateau date of 16.32 +/- 0.13 Ma, and adularia from Opitonui yields a preferred 40Ar/39Ar age of 13.15 +/- 0.03 Ma. Two Re-Os dates of molybdenite from porphyry-style mineralization at Ohio Creek overlap within error and yield dates of 11.87 +/- 0.06 and 11.97 +/- 0.08 Ma; geologic relationships suggest that this is the likely age of mineralization in the nearby Thames epithermal deposits. In the eastern province, adularia from the Ohui deposit gives a preferred 40Ar/39Ar age of 8.29 +/- 0.25 Ma, adularia from the Broken Hills deposit gives a preferred 40Ar/39Ar age of 7.12 +/- 0.02 Ma, and adularia from the Wharekirauponga prospect yields a preferred Ar-10/39Ar age of 6.32 +/- 0.12 Ma. In the southern province, adularia from quartz veins at the Maratoto deposit provide a preferred 40Ar/39Ar age of 6.41 +/- 0.04 Ma, and adularia from a quartz vein at the Sovereign deposit yields a preferred 40Ar/39Ar age of 6.70 +/- 0.16 Ma. Two dates from vein adularia at the world-class Martha deposit overlap within error, and we interpret a preferred age for the deposit of 6.16 +/- 0.06 Ma. Two samples of molybdenite from veins in the Martha deposit yield discrete Re-Os dates of 6.37 +/- 0.03 and 6.51 +/- 0.03 Ma. Adularia from one quartz vein from the Favona deposit yields a 40Ar/39Ar date of 6.05 +/- 0.04 Ma. Host rock and vein adularia from the Karangahake deposit yield 40Ar/39Ar plateau dates that range from 6.90 +/- 0.20 to 5.71 +/- 0.13 Ma, which may reflect more than one stage of mineralization or protracted fluid flow. Adularia from veins at the Waiorongomai deposit yields,a preferred 40Ar/39Ar age of 5.71. +/- 0.03 Ma, and adularia from a vein at the Eliza deposit yields a preferred age of 4.47 +/- 0.06 Ma. The southernmost deposit in the Hauraki goldfield, Muirs Reef, has adularia in quartz veins that yield 40Ar/39Ar plateaus dates of 2.12 +/- 0.11 to 1.78 +/- 0.16 Ma. In the northern province of the goldfield, adularia from Paritu yields a single 40Ar/39Ar plateau date of 16.32 +/- 0.13 Ma, and adularia from Opitonui yields a preferred 40Ar/39Ar age of 13.15 +/- 0.03 Ma. Two Re-Os dates of molybdenite from porphyry-style mineralization at Ohio Creek overlap within error and yield dates of 11.87 +/- 0.06 and 11.97 +/- 0.08 Ma; geologic relationships suggest that this is the likely age of mineralization in the nearby Thames epithermal deposits. In the eastern province, adularia from the Ohui deposit gives a preferred 40Ar/39Ar age of 8.29 +/- 0.25 Ma, adularia from the Broken Hills deposit gives a preferred 40Ar/39Ar age of 7.12 +/- 0.02 Ma, and adularia from the Wharekirauponga prospect yields a preferred Ar-10/39Ar age of 6.32 +/- 0.12 Ma. In the southern province, adularia from quartz veins at the Maratoto deposit provide a preferred 40Ar/39Ar age of 6.41 +/- 0.04 Ma, and adularia from a quartz vein at the Sovereign deposit yields a preferred 40Ar/39Ar age of 6.70 +/- 0.16 Ma. Two dates from vein adularia at the world-class Martha deposit overlap within error, and we interpret a preferred age for the deposit of 6.16 +/- 0.06 Ma. Two samples of molybdenite from veins in the Martha deposit yield discrete Re-Os dates of 6.37 +/- 0.03 and 6.51 +/- 0.03 Ma. Adularia from one quartz vein from the Favona deposit yields a 40Ar/39Ar date of 6.05 +/- 0.04 Ma. Host rock and vein adularia from the Karangahake deposit yield 40Ar/39Ar plateau dates that range from 6.90 +/- 0.20 to 5.71 +/- 0.13 Ma, which may reflect more than one stage of mineralization or protracted fluid flow. Adularia from veins at the Waiorongomai deposit yields,a preferred 40Ar/39Ar age of 5.71. +/- 0.03 Ma, and adularia from a vein at the Eliza deposit yields a preferred age of 4.47 +/- 0.06 Ma. The southernmost deposit in the Hauraki goldfield, Muirs Reef, has adularia in quartz veins that yield 40Ar/39Ar plateaus dates of 2.12 +/- 0.11 to 1.78 +/- 0.16 Ma. In the northern province of the goldfield, adularia from Paritu yields a single 40Ar/39Ar plateau date of 16.32 +/- 0.13 Ma, and adularia from Opitonui yields a preferred 40Ar/39Ar age of 13.15 +/- 0.03 Ma. Two Re-Os dates of molybdenite from porphyry-style mineralization at Ohio Creek overlap within error and yield dates of 11.87 +/- 0.06 and 11.97 +/- 0.08 Ma; geologic relationships suggest that this is the likely age of mineralization in the nearby Thames epithermal deposits. In the eastern province, adularia from the Ohui deposit gives a preferred 40Ar/39Ar age of 8.29 +/- 0.25 Ma, adularia from the Broken Hills deposit gives a preferred 40Ar/39Ar age of 7.12 +/- 0.02 Ma, and adularia from the Wharekirauponga prospect yields a preferred Ar-10/39Ar age of 6.32 +/- 0.12 Ma. In the southern province, adularia from quartz veins at the Maratoto deposit provide a preferred 40Ar/39Ar age of 6.41 +/- 0.04 Ma, and adularia from a quartz vein at the Sovereign deposit yields a preferred 40Ar/39Ar age of 6.70 +/- 0.16 Ma. Two dates from vein adularia at the world-class Martha deposit overlap within error, and we interpret a preferred age for the deposit of 6.16 +/- 0.06 Ma. Two samples of molybdenite from veins in the Martha deposit yield discrete Re-Os dates of 6.37 +/- 0.03 and 6.51 +/- 0.03 Ma. Adularia from one quartz vein from the Favona deposit yields a 40Ar/39Ar date of 6.05 +/- 0.04 Ma. Host rock and vein adularia from the Karangahake deposit yield 40Ar/39Ar plateau dates that range from 6.90 +/- 0.20 to 5.71 +/- 0.13 Ma, which may reflect more than one stage of mineralization or protracted fluid flow. Adularia from veins at the Waiorongomai deposit yields,a preferred 40Ar/39Ar age of 5.71. +/- 0.03 Ma, and adularia from a vein at the Eliza deposit yields a preferred age of 4.47 +/- 0.06 Ma. The southernmost deposit in the Hauraki goldfield, Muirs Reef, has adularia in quartz veins that yield 40Ar/39Ar plateaus dates of 2.12 +/- 0.11 to 1.78 +/- 0.16 Ma. In the northern province of the goldfield, adularia from Paritu yields a single 40Ar/39Ar plateau date of 16.32 +/- 0.13 Ma, and adularia from Opitonui yields a preferred 40Ar/39Ar age of 13.15 +/- 0.03 Ma. Two Re-Os dates of molybdenite from porphyry-style mineralization at Ohio Creek overlap within error and yield dates of 11.87 +/- 0.06 and 11.97 +/- 0.08 Ma; geologic relationships suggest that this is the likely age of mineralization in the nearby Thames epithermal deposits. In the eastern province, adularia from the Ohui deposit gives a preferred 40Ar/39Ar age of 8.29 +/- 0.25 Ma, adularia from the Broken Hills deposit gives a preferred 40Ar/39Ar age of 7.12 +/- 0.02 Ma, and adularia from the Wharekirauponga prospect yields a preferred Ar-10/39Ar age of 6.32 +/- 0.12 Ma. In the southern province, adularia from quartz veins at the Maratoto deposit provide a preferred 40Ar/39Ar age of 6.41 +/- 0.04 Ma, and adularia from a quartz vein at the Sovereign deposit yields a preferred 40Ar/39Ar age of 6.70 +/- 0.16 Ma. Two dates from vein adularia at the world-class Martha deposit overlap within error, and we interpret a preferred age for the deposit of 6.16 +/- 0.06 Ma. Two samples of molybdenite from veins in the Martha deposit yield discrete Re-Os dates of 6.37 +/- 0.03 and 6.51 +/- 0.03 Ma. Adularia from one quartz vein from the Favona deposit yields a 40Ar/39Ar date of 6.05 +/- 0.04 Ma. Host rock and vein adularia from the Karangahake deposit yield 40Ar/39Ar plateau dates that range from 6.90 +/- 0.20 to 5.71 +/- 0.13 Ma, which may reflect more than one stage of mineralization or protracted fluid flow. Adularia from veins at the Waiorongomai deposit yields,a preferred 40Ar/39Ar age of 5.71. +/- 0.03 Ma, and adularia from a vein at the Eliza deposit yields a preferred age of 4.47 +/- 0.06 Ma. The southernmost deposit in the Hauraki goldfield, Muirs Reef, has adularia in quartz veins that yield 40Ar/39Ar plateaus dates of 2.12 +/- 0.11 to 1.78 +/- 0.16 Ma.