Thermal Evolution History and Its Genesis of the Ailao Shan-Red River Fault Zone in the Ailao Shan and Day Nui Con Voi Massif during Oligocene-Early Miocene
Gong Wei
Jiang Xiaodian
Abstract：In spite of much research focused on thermal evolution history-tectonic activity of the Ailao Shan-Red River fault zone (ASRR) during Late Oligocene-Early Miocene,its thermal reconstruction is limited.Moreover,the related thermal disturbance factors are often ignored and the measured ages (cooling ages) are generally irrationally recognized as the timing of tectonic events in the existing studies.Combined with the pressure-temperature-depth paths (P-T-D) and paleogeomorphology reconstruction,the T-t paths of the ASRR are constructed to explore the genesis of T-t paths and the evolutionary characteristics of the fault zone systematically.The cooling process of the metamorphic massif can be divided into two phases:for Day Nui Con Voi is 32-30 Ma and 26-24 Ma,while for the Ailao Shan is 32-22 Ma and 22-20 Ma.In the first phase,the rapid cooling may have been caused by the strata denudation or tectonic denudation,followed by the more rapid cooling of the second phase,in which the intensity weakening of the fault has been more dominant,compared with the denudation and other factors.With the clockwise rotation and extrusion of the Indochina terrane relative to the South China block,the sinistral tensile transformation zone in the south propagated northwards.Additionally,the spatial differences in the tectonic activities induced the varied cooling processes for the southeastern and northwestern part.In phase Ⅰ,the tectonic uplift in the southeastern part presented earlier and stronger than the northwestern one,with the northwestward propagation and weakening of the sinistral tensile transformation.So the cooling process of the southeastern part was much earlier and more rapid,compared with the northwestern process.In phase Ⅱ,the activity of the ASRR which acted as the boundary of the plate extrusion became weak northwards,along with a new period of Tibet uplift in early Miocene.Then the change stimulated another rapid cooling process,showing the northwestward decreasing trend.
Keywords：the Ailao Shan-Red River fault zoneOligoceneMiocenesinistral strike-slipstrata denudationthe fault activitythermochronology
Publication Date：2017-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：17( 223-239 )