The basin tectonic model: it is intermont basin during late Jurassic to early Cretaceous, developed into faulted-lacustrine basin in Eogene, and evolved into depression in Neogene and Quaternary.
“盆
”构造发育模式为:从晚侏罗世到

末期发育的山间“盆
”开始、发展到早第三
断陷湖盆的发育、再演化为晚第三
及第

陷发育阶段。


在中新世中
到大量其化石的时候。
第四

第四


