关键词: 碎屑沉积物, 锆石, U-Pb年龄, 地球化学, 黄河口河流, 山东东营

Abstract:

Terrigenous clastic sedimentary rocks (sediments) are natural mixture of their provenance materials, preserving important information of different processes on their provenances, which can usually be used as key clues of processes of basin sedimentation, regional tectonic, crustal growth and evolution, and reconstruction of ancient continent. Zircon U-Pb age studies of river sand from the outfall of the Yellow River in Dongying, Shandong Province, together with grain size analysis of detrital components and constituent of heavy minerals, show that the main size of river sand in the outfall of the Yellow River ranges from 10 to 280 μm. Heavy minerals are composed of hornblende, hematite-limonite, garnet, epidote, magnetite, etc. Detrital zircons in the outfall of the Yellow River are igneous origin with multiple populations of ages. The maximum concordant U-Pb age is~3.65 Ga, which reflects the existence of over 3.6 Ga crustal material in the other areas apart from Anshan, Liaoning Province and eastern Hebei Province. Zircon ages mainly distribute in 206-440 Ma, 843-1,239 Ma, 1,476-2,714 Ma, peakings at ~2.5 Ga, ~1.8 Ga and 400 Ma. The two peaks of around ~2.5 Ga and~1.8 Ga show contribution of the North China Block. The 400 Ma peak and ages between 1,000 and 800 Ma represent input materials that came from the Su-Lu Orogenic Belt. Together with previous studies, 2.5-1.8 Ga should be the main growth stage of continent for the provenance crust of the Yellow River's draining area, and over 60% crust was formed at that time.

Key words: clastic sediment, zircon, U-Pb age, geochemistry, the outfall of the Yellow River, Dongying, Shandong Province