Detrital Zircon U-Pb Age Study of the Paleozoic－Mesozoic Sedimentary Rocks, Southwestern Fujian
Date Issued
2011
Date
2011
Author(s)
Zul, Zugeerbai
Abstract
Abstract
The study is in located in the Southwest of Fujian Province, sandstone samples were collected from the Cambrian to Ordovician metamorphic rocks, and the Devonian to Jurassic sedimentary rocks. Detrital zircons of the Paleozoic-Mesozoic strata rocks were separated from10 samples by LA-ICP-MS measurements for U-Pb dating.
The Southern China region undergo several plate collision, results in many phase tectonic activities, causing the variabilities of sequence stratigraphy, tectonic, and sedimentary environment.
Result from the U-Pb dating, it indicates that the Jinning orogeny, Caledonian orogeny, Indosinian and Yanshanian magmatic detrital zircons re-accumulation of geological sigifcance. The comparison of these tectonic movements Caledonian, Indosinian and Yanshanian seems to slightly change of detrital zircon ages.
The detrital zircon age assemblidge of Caledonian indicates that >2400 Ma (Wutai movement), 1700-1000 Ma, 1000-930 Ma (Sibao movement) higher proportion of about 95%. Some of igneous zircons deposite in the time without tectonic movement (1700-1000Ma). This study suggests that there remain sporadic igneous activity, such as the 750-450 Ma can be found in Fujian province during the sporadic distribution of igneous rocks.
From the Caledonian movement and after, because nearly 40% from this period of igneous detrital zircons , with the result >750 Ma detrital zircons significantly reduced the proportion of the total, but this period is >2400 Ma and 850-750Ma for proportion of detrital zircon and more. The reason is Caledonian movement may cause the early Paleozoic, and Sinian strata exposed, resulting in 750-450 Ma and 850-750 Ma a higher proportion of the old in >2400 Ma detrital zircons more reasons, this study still can’t explain.
Indosinian movement period, >750 Ma detrial zircon tended to decrease, probably a lot of volcanic rocks covering the surface gradually caused. But Indosinian movement 1900-1700 Ma (Luliang movement) the proportion of detrital zircons have a very high proportion of about 18%; Luliang movement is the main formation period the Catashyia, constitute the main base Catashyia, now exposed in Fujian northwest region, knows as Mayuan group.
During the Indosinian movement, South China region the formation of large areas fault and folding result in a large basement area Cathaysia exposed surface, and become the main source.
Subjects
Detrital zircon
Paleozoic to Mesozoic
Type
thesis
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