The Cavezzo meteorite, which fell on January 1, 2020, is the first meteorite detected and recovered by the Italian PRISMA Fireball Network. Two specimens, weighing 3.12 g (specimen 1) and 52.19 g (specimen 2), were collected 3 days after the bolide was observed, thanks to an effective media campaign that encouraged the involvement of local people. The two specimens of this meteorite have not only completely different lithological characteristics but also a different geochemistry and oxygen isotopic composition as well. Specimen 1 is anomalous both for the textural–structural features, varying seamlessly from chondritic to “achondritic,” and a very unusual modal mineralogy—such as the relatively high amount of olivine (63.1 vol%), plagioclase (18.2 vol%), high-Ca pyroxene (10.3 vol%), and chlorapatite (2.1 vol%); and the unusually low content of low-Ca pyroxene (5.8 vol%), metal (0.1 vol%), and troilite (much lesser than 0.1 vol%)—although the compositional values for olivine (Fa 24.24 mol%) and low-Ca pyroxene (Fs 20.41 mol%) appear to be similar to those of the L chondrite group. Conversely, in specimen 2, not only the texture and the crystal chemistry but also the modal mineralogy (low-Ca pyroxene much more abundant than high-Ca pyroxene and occurrence of metal and sulfides) look like those of an ordinary L chondrite. The differences between the two specimens are also confirmed by geochemistry. The oxygen isotope composition of specimen 1 plots at the boundary between the H and L groups (δ¹⁷O‰ 3.250; δ¹⁸O‰ 4.736; Δ¹⁷O‰ 0.788) whereas specimen 2 plots at the boundary of the L and LL fields (δ¹⁷O‰ 3.737; δ¹⁸O‰ 4.957; Δ¹⁷O‰ 1.159). The bulk chemistry shows a different content of many minor and trace elements (including rare earth elements), such as a strong depletion of siderophile and chalcophile elements in specimen 1. The two specimens then do not contain fragments of each other, thus preventing us from classifying this “double face” meteorite as an ordinary chondrite breccia. In detail, specimen 1 can be considered a “xenolith” in which chondritic structure and igneous texture coexist without discontinuity, and therefore, it represents a previously unsampled portion of the L parent body. In summary, these findings support the classification of Cavezzo as an L5 anomalous chondrite.

中文翻译：

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卡维佐——陨石的双面：一种非常不寻常的球粒陨石的矿物学、岩石学和地球化学

Cavezzo 陨石于 2020 年 1 月 1 日坠落，是意大利 PRISMA 火球网络发现并回收的第一颗陨石。由于鼓励当地人参与的有效媒体宣传活动，在观察到火爆后 3 天收集了两个重 3.12 克（样本 1）和 52.19 克（样本 2）的样本。这块陨石的两个标本不仅具有完全不同的岩性特征，而且地球化学和氧同位素组成也不同。标本 1 的质地结构特征异常，从球粒状到“无球粒状”无缝变化，以及非常不寻常的矿物形态——例如相对大量的橄榄石 (63.1 vol%)、斜长石 (18.2 vol%)、高-Ca辉石（10.3 vol%）和氯磷灰石（2.1 vol%）；以及异常低含量的低钙辉石 (5.8 vol%)、金属 (0.1 vol%) 和硫磷矿（远小于 0.1 vol%）——尽管橄榄石的成分值（Fa 24.24 mol%）和低钙辉石 (Fs 20.41 mol%) 似乎与 L 球粒陨石群相似。相反，在样品 2 中，不仅质地和晶体化学，而且模态矿物学（低 Ca 辉石比高 Ca 辉石丰富得多，金属和硫化物的出现）看起来像普通 L 球粒陨石。地球化学也证实了两个标本之间的差异。试样 1 的氧同位素组成绘制在 H 和 L 基团之间的边界处 (δ 24 mol%) 和低 Ca 辉石 (Fs 20.41 mol%) 似乎与 L 球粒陨石群相似。相反，在样品 2 中，不仅质地和晶体化学，而且模态矿物学（低 Ca 辉石比高 Ca 辉石丰富得多，金属和硫化物的出现）看起来像普通 L 球粒陨石。地球化学也证实了两个标本之间的差异。试样 1 的氧同位素组成绘制在 H 和 L 基团之间的边界处 (δ 24 mol%) 和低 Ca 辉石 (Fs 20.41 mol%) 似乎与 L 球粒陨石群相似。相反，在样品 2 中，不仅质地和晶体化学，而且模态矿物学（低 Ca 辉石比高 Ca 辉石丰富得多，金属和硫化物的出现）看起来像普通 L 球粒陨石。地球化学也证实了两个标本之间的差异。试样 1 的氧同位素组成绘制在 H 和 L 基团之间的边界处 (δ 地球化学也证实了两个标本之间的差异。试样 1 的氧同位素组成绘制在 H 和 L 基团之间的边界处 (δ 地球化学也证实了两个标本之间的差异。试样 1 的氧同位素组成绘制在 H 和 L 基团之间的边界处 (δ¹⁷ O‰ 3.250; δ ¹⁸ O‰ 4.736；Δ ¹⁷ O‰ 0.788) 而样本 2 在 L 和 LL 场的边界处绘图 (δ ¹⁷ O‰ 3.737; δ ¹⁸ O‰ 4.957; Δ ¹⁷O‰ 1.159）。大宗化学显示许多微量元素和微量元素（包括稀土元素）的含量不同，例如样品 1 中亲铁元素和亲硫元素的强烈消耗。然后两个样品不包含彼此的碎片，从而防止我们将这种“双面”陨石归类为普通球粒陨石角砾岩。详细地说，标本 1 可以被认为是一个“捕虏体”，其中球粒状结构和火成岩结构共存而没有间断，因此，它代表了 L 母体的先前未采样部分。总之，这些发现支持将 Cavezzo 归类为 L5 异常球粒陨石。