The Mesozoic volcanic rocks around Songliao Basin mainly erupted during J3-K1 coexisting with coal-bearing strata . There is adistance of 1000-2000 km from there to the paleosuture. There is no composition polarity for the volcanic rocks from east to west around Songliao Basin. Main magmatic series is high K-calc-alkali series. Main rocks assemblages are potassic trachybasalt-shoshonite-latite-trachyte-trachydasite-high K-rhyolite. The geochemical property of these volcanic rocks shows the character of an orogenic belt of volcanic rocks. But it differentiates from island arc volcanic rocks of subduction zone in some way. Isotope composition of the volcanic rocks from Pinggang-Weijin Basin shows middle Sr, lower Nd and absence in ocean crust composition. It is recognized that the Mesozoic volcanic rocks around Songliao Basin are the product of supercomposed continental margin active belt during adjusting of lithosphere under the background of extension but not direct product of subduction of the Pacific Plate. These volcanic rocks can be called volcanic rocks assemblage in active belt of spreading type of continental margin.
|Journal||Acta Petrologica Sinica|
|Publication status||Published - 1997|
- Around songliao basin
- Background of extension
- Continental margin
- Rocks assemblages