四川某石化地块生产区土壤中石油烃污染分布特征研究

文章以四川某石化企业搬迁场地为研究对象,以保护生态环境、保障人体健康为目的,以该行业特征污染物石油烃(C_(10)~C_(40))为例,详述其在该地块土壤中的污染分布特征,为四川省石化行业企业遗留地块污染调查评估提供借鉴。

Discovery of late Paleozoic fossils in tectonic blocks of the Dabao Formation in the South Qinling Orogenic Belt and their significance

The Dabao Formation in the South Qinling Orogenic Belt was previously regarded as Ordovician in age and consists of clastic matrix and blocks of siltstone,limestone,chert,and volcanic rocks.However,some Middle Devonian corals,conodonts,and other fossil fragments within the limestone blocks were discovered in recent field investigations,indicating that the Dabao Formation was formed during late Paleozoic.Combined with other regional geological data,the Dabao Formation in the Southern Qinling Orogenic Belt is considered to be a late Paleozoic or early Mesozoic accretionary complex.

Paleomagnetic data from the Late Carboniferous-Late Permian rocks in eastern Tibet and their implications for tectonic evolution of the northern Qiangtang-Qamdo block

We report paleomagnetic results from the Late Carboniferous-Late Permian strata in eastern Tibet (China), and aim to clarify the tectonic and paleogeographic evolution of the northern Qiangtang-Qamdo block, which is the key to the study of plate boundary between the Gondwanaland and the Eurasia during the late Paleozoic. Two hundred and nineteen samples-including limestone, muddy siltstone, basalt, lava, and tuff-were collected at 24 sites in the Upper Carboniferous and Middle-Upper Permian successions. A systematic study of rock magnetism and paleomagnetism yields three reliable paleomagnetic pole positions. Both hematite and magnetite occurred in the Late Carboniferous limestone samples. The demagnetization curve shows a characteristic double-component, with the remanent magnetization (ChRM) exhibiting a positive polarity (negative inclination). In the Late Permian limestone, tuff, and basalt, magnetic information were recorded primarily in magnetite, although a small fraction of them was found in hematite in basalt. The demagnetization curve illustrates a double or single component, with the ChRM showing a negative polarity (positive inclination), which has passed the classic fold test successfully. The single polarity features of the ChRM directions of the Late Carboniferous and Middle-Late Permian rocks are respectively related to the Kiaman positive and reversed polarities under the stratigraphic coordinates. This, in turn, indicates that both ChRMs directions represent the original remanence directions. By comparison with the previously published paleomagnetic results from the late Paleozoic rocks in the northern Qiangtang Range, we suggest that: (1) Qamdo and northern Qiangtang block were independent of each other during the Late Carboniferous to the Early Permian periods. The north Lancangjiang ocean basin between the two blocks may have closed before the Middle Permian and been involved in the continent-continent collision stage in the Late Permian-Early Triassic periods. (2) The northern Qiangtang-Qamdo Block paleogeographically was situated at low to intermediate latitudes in the Southern Hemisphere in the Late Carboniferous-Late Permian periods, and began to displace northward in the Early Triassic, with an amount of more than 5000 km northward transport from its current location.