Clinopyroxene megacrysts occurring in Cenozoic mafic alkaline volcanic rocks from the northern margin of the Bohemian Massif (SW Poland, SE Germany) could be subdivided by colour and Mg# (Mg/(Mg + Fe^tot)) in three groups. Megacryst with the highest Mg# = 90.0–91.5 (“high Mg#”, HMg#) is transparent and strongly Light Rare Earth Element (LREE) depleted and contains abundant orthopyroxene lamellae. The clinopyroxene megacrysts with “medium Mg#” (MMg#) values (76.8–83.4) are transparent to light grey and are all LREE-enriched. The group with the lowest Mg# (LMg#; 62.2–74.6) is intensively coloured (from grey to green) and may enclose apatite, Ti-magnetite or pseudomorphs after amphibole. The “low Mg#” (LMg#) clinopyroxenes are LREE-enriched, and some display positive Zr–Hf anomalies.

The single HMg# megacryst records pressures ~1GPa and temperature of 1280 °C, pointing to its mantle origin. It is the first megacryst described in European lavas and possibly worldwide, which shows affinity to Depleted MORB Mantle (DMM). The MMg# megacrysts formed from fractionating mafic magmas at variable pressures and temperatures – from those corresponding to mantle depths (>1 GPa, 1230–1350 °C) to lower/middle crustal values (0.5–0.9 GPa, 1120–1150 °C). The parental melts for this group are isotopically related to the Cenozic volcanic rocks from the study area. The LMg# megacrysts crystallized from strongly alkaline melts, mostly at lower- to middle-crustal pressures (0.4–1.0 GPa). Their parental melts were also related to Cenozoic volcanism, but their strongly evolved nature resulted in local, but significant enrichment in Zr and Hf. The LMg# megacrysts from three localities in Poland are the first evidence of strongly alkaline magmatism in the north-easternmost part of Cenozoic European Volcanic Province.

来自波希米亚地块北缘（波兰西南，德国）的新生代镁铁质碱性火山岩中出现的斜辉石大晶体可以按颜色和Mg＃（Mg /（Mg + Fe ^tot））细分为三类。Mg＃= 90.0–91.5的超晶（“ Mg＃高”，HMg＃）是透明的，并且已被消耗的轻稀土元素（LREE）强烈，并且含有丰富的邻苯二甲撑薄片。具有“ Mg＃中号”（MMg＃）值（76.8–83.4）的斜辉石大晶透明至浅灰色，并且全部富含LREE。Mg＃（LMg＃; 62.2–74.6）最低的组着色强烈（从灰色到绿色），并且在闪石后可能包含磷灰石，钛磁铁矿或假晶。“低Mg＃”（LMg＃）斜环茂铁富含LREE，并且有些Zr-Hf呈正异常。

单个HMg＃巨晶记录了约1GPa的压力和1280°C的温度，指向其地幔起源。它是欧洲熔岩中乃至世界范围内描述的第一种超大结晶，显示出与贫化MORB幔（DMM）的亲和力。MMg＃巨晶是由在不同压力和温度下分离铁镁质岩浆形成的-从对应于地幔深度（> 1 GPa，1230–1350°C）到较低/中地壳值（0.5–0.9 GPa，1120–1150°C）形成。该组的母体熔体与研究区的新生代火山岩同位素相关。LMg＃巨晶是从强碱性熔体中结晶的，大部分处于中低地壳压力（0.4-1.0 GPa）下。它们的亲本熔体也与新生代火山作用有关，但是它们的强烈演化性质导致了Zr和Hf的局部富集。