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广东从化恶鸡脑碱性正长岩岩体是广东乃至华南地区唯一已知的中生代含副长石及碱性暗色矿物的碱性正长岩岩体。岩石含有霞石、白榴石及岩浆成因的方钠石。碱性正长岩体侵入到燕山期第三期的佛冈岩体之中，岩体侵位年龄为127.5Ma(角闪石Ar-Ar法)。岩体富大离子亲石元素，贫Sr和Ba,具有明显的铕负异常，富Nb和Zr等高场强元素。εNd(t)为近于零的负值（－0.66～－1.6）,模式年龄tDM较小（0.91～0.99Ga）,钕同位素组成显示出其成岩物质主要源于富集的上地幔源区。造山后准铝质A型花岗岩[(158±17)Ma]-非造山A型花岗岩(～132Ma)-碱性正长岩(127.5Ma)的构造岩浆组合，是侏罗纪中国东南部由挤压造山向拉张伸展转变的产物,表明华南地区岩石圈拉张作用应始于晚侏罗世。具有铕负异常的碱性正长岩的产出,标志着早白垩世造山作用的结束、山根消失及大规模拉张构造事件的开始。
Guangdong Conghua bad chicken brain alkaline syenite is the only known in Guangdong Province and southern China Mesozoic ancillary rocks and alkaline dark minerals alkaline syenite body. Rock contains nepheline, leucite and magma origin of sodalite. Alkaline syenite intrusions intruded into the third phase of the Yanshanian Fogang granite, with an emplacement age of 127.5 Ma (amphibole Ar-Ar method). The rock mass is rich in large ion lithophile elements, depleted in Sr and Ba, has obvious negative anomalies of europium and is rich in field strength elements such as Nb and Zr. εNd (t) is negative near zero (-0.66 ~ -1.6), mode tDM is small (0.91 ~ 0.99Ga), neodymium isotope composition shows that the diagenetic material is mainly derived from the enriched upper mantle source. After orogeny, the quasi-aluminum A-type granites [(158 ± 17) Ma] -structural magmatic assemblages of non-orogenic A-type granites (~ 132Ma) -alkaline syenite (127.5Ma) were formed by squeezing the southeastern part of Jurassic The product of the transformation of extensional extensional tectonics shows that the lithospheric extension in southern China should begin in the Late Jurassic. The production of alkaline anorthosols with negative anomalies of europotential signifies the end of the Early Cretaceous orogeny, the disappearance of the root of a mountain and the start of large-scale tensile structural events.