U th he dating of apatite a potential thermochronometer dating com and ua
The Sanshandao Au deposit is a typical fault-controlled one, and two interesting features make it attractive for thermochronology studies: (i) previous fluid inclusion thermobarometric results suggested pervasive denudation (, but the exact timing and mechanism of the exhumation has not been previously studied; and (ii) hydrothermal alteration envelops both the hanging wall and footwall, but orebodies have only been discovered in the footwall.Determining the fault offset direction and quantifying the offset magnitude will assist exploration and impact reserve estimation. AUTHORS:20121120-132902967 Full text is not posted in this repository. Use this Persistent URL to link to this item: AUTHORS:20121120-132902967Apatite (U–Th)/He apparent ages will generally reflect residence for extended periods at temperatures where helium is neither quantitatively retained nor lost by diffusion.He ages within the partial retention zone ultimately achieve a balance between He production and loss, yielding a steady state age.1500 tons, however little is known about the history of exhumation, and the magnitude of displacement on the ore-hosting fault.
The results illustrate the sensitivity of He ages to various geologic histories and are useful for understanding He age–elevation relationships and for testing time–temperature paths derived from apatite fission track length distributions. suggested that the NE-trending Jiaojia-Xincheng fault (JXF) experienced normal faulting from 135 Ma to 120 Ma, and a sinistral slip from 120–110 Ma, which was followed by normal displacement at ca. From 80–60 Ma, the fault acted as a normal fault, followed by a dextral reactivation at ca. Maps showing the location (a) and general geology (b) of Jiaodong; Geologic maps showing the Sanshandao-Cangshang belt (c) and sampling localities (d); CN: China, NK: North Korea, SK: South Korea, SCF: Sanshandao-Cangshang fault, JXF: Jiaojia-Xincheng fault, ZPF: Zhaoyuan-Pingdu fault, UHP: ultra-high pressure; the paleostress directions in Fig. Numbers in the parentheses after the sample number represent sampling depth. The Sanshandao Au deposit is hosted by the Sanshandao-Cangshang fault (SCF), and to its south are two mining camps (Xinli and Cangshang) (Fig. To its north, the fault extends into Bohai Bay, and recent exploration drilling discovered large orebodies with 470 tons Au resource in the undersea region. The ore bodies are commonly several meters thick and localized only in the footwall rocks.Figure 1a was made with data from Google Maps (https:// and was reproduced using Corel DRAW × 6 ( They comprise disseminated-style sulfides enclosed by envelopes of strong silicification proximal to the fault, trending to sericitization and potassic alteration with increasing distance from the fault.Exhumation magnitude estimates suggest that the deposit have been denudated .
Understanding the timing of exhumation and exposure of hypogenic Au deposits is of particular interest to the exploration community given the implications for preservation of ore deposits and the host terrain, respectively, spanning the low temperature history of a hydrothermal Au deposit, and providing important insights on these processes.Despite of intra-sample dispersions, (U-Th)/He ages from two sub-vertical profiles show decreasing trends from the surface down to −3560 m (zircon: 123 Ma to 55 Ma; apatite 103 Ma to 0.3 Ma).