U-Pb dating of single detrital zircon grains from Mesozoic sandstone in the Beipiao Basin in the eastern Yan-Liao Orogenic Belt, China: provenance and correlation of tectonic evolution

摘要

Single grain U-Pb ages of sediments from the Beipiao Basin, Northeast China were conducted to determine the evolution of basin provenance. Zircons from a sandstone in the Upper Triassic Laohugou Formation yield a wide range of ages and, according to their U-Pb ages, fall into four groups: 209.3 +/- 4.0-304.2 +/- 4.9, 1565.5 +/- 71-2154 +/- 50, 2400 35-2499 +/- 9, 2512 +/- 11-2557 +/- 74 Ma. These ages indicate that the zircons were principally derived from Late Archean, Proterozoic and Late Paleozoic plutonic rocks. Intrusions in the Mongolian Accretion Belt and the northern margin of the North China Block (NCB) were probably the main source of the sediments in the basin, but the easterly Liaodong Block also provided minor detrital material, with lower U-Pb ages, during the Late Triassic. Most of the U-Pb ages from zircons collected from a sandstone in the Lower Jurassic Beipiao Formation range from 194.3 +/- 2.9 to 233.8 +/- 4.2 Ma, reflecting the major sediment source during the Early Jurassic. Zircons derived from Late Indosinian plutonic rocks increased, which suggests that the detritus was supplied mainly from the interior of the Yan-Liao Orogenic Belt, especially from the Liaodong Block. Late Indosinian zircons (200-230 Ma) were eroded and deposited in the Lower Jurassic Beipiao Formation, and this implies that intensive tectonic activation and uplift of the Yan-Liao Orogenic Belt in the Mesozoic commenced in the Late Indosinian. (c) 2005 Elsevier Ltd. All rights reserved.