摘要
磷灰石裂变径迹年代学已经被广泛地应用于山体隆升、限定潜在物源区、沉积盆地后期的抬升时间等方面的研究。通常情况下，无论是基岩隆升，还是碎屑沉积地层的后期抬升，磷灰石裂变径迹年龄出现的“拐点”都具有重要的地质意义。本文从磷灰石裂变径迹的年龄形成机制、径迹封闭温度、径迹退火基本概念入手，总结了碎屑和基岩磷灰石裂变径迹年龄出现的拐点的基本意义，并针对每个具体的应用给出了研究实例。在碎屑磷灰石中，未发生强烈退火的径迹年龄形成的两阶段和单阶段移动峰，可限定物源变化的时间以及约束潜在物源区。完全退火后，新形成的径迹年龄拐点，可限定地层的变形时间。岩体经历快速隆升，在一定高程范围内的径迹年龄彼此接近，与部分退火带相接的部位会出现拐点。
Fission track analysis provides detailed information on the low temperature thermal histories of rocks, and it has been wildly applied to a variety of geological problems, including the exhumation time of the mountains, sedimentary provenance, thermal history modeling of sedimentary basins, etc. In general, the “inflection point” of the apatite fission track ages are not only associated with an bedrock exhumation but also with the uplift of sedimentary strata. Here, we present some essential definitions and concepts regarding the apatite fission track, and how the fission track developed over the geologic time. And then, we have summarized the main types of the “inflection point” of apatite fission track in the detrital and bedrock, respectively. At last, we highlight a few examples of recent studies to make the readers better understanding the “inflection point”. Provided the detrital apatite grains have not experienced strong annealing, the moving peaks coupled the depositional age can be used to constrain the time of provenance changing and potential source areas. However, when the grains have undergone post-depositional annealing, the minimum age can be particularly useful to determine the timing of structural deformation for the host sediment. In the case of the bedrock, the “inflection point” could appear between the partial annealing zone and rapid cooling belt which the ages were close to each other.
出处
《第四纪研究》
CAS
CSCD
北大核心
2017年第3期570-580,共11页
Quaternary Sciences
关键词
磷灰石
裂变径迹
年龄拐点
apatite, fission track, inflection point
