Venus tessera terrain contains the oldest rocks preserved on the surface of the planet. The composition of the tesserae is unknown, but recent observations of near‐infrared emissivity from orbit suggest that they are silica rich. This contrasts with previous interpretation that silica‐rich rheologies are too weak to produce tessera folds. We examine the range of compositions consistent with the observed folds in the tessera. We map folds in Tellus Regio tessera using the highest resolution Magellan radar images (∼100 m) and stereo topography (∼1 km). We use fold spacings as input into a buckling analysis that simulates power law rheology using contemporary dry‐mineral flow laws and modeled igneous rock compositions, consistent with a predicted dry lithosphere for Venus in the recent era. The folds have dominant wavelengths of 6–19 km with amplitudes of 500–1,000 m, consistent with low strains (1%–12%). We confirm that observed folds require heat flows of ≥40 K/km and strain rates faster than 10⁻¹⁶s⁻¹, higher than today. These low strain folds are unlikely to have significantly modified the preexisting tessera surface, thus older impact craters must have been removed by an earlier geologic process. We demonstrate that the folds can form in dry crust with a SiO₂ content ranging from 48% to 72%. Dry felsic rheologies could explain low emissivity signatures of tesserae that are attributed to a low Fe²⁺. If felsic, tessera materials may have formed in a prior era via partial melting of hydrous materials derived from recycling of surface waters into the Venus mantle.

中文翻译：

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岩石圈变形模型允许的金星上的Felsic Tesserae

维纳斯·泰塞拉（Venus tessera）地形包含保存在地球表面的最古老的岩石。镶嵌的成分尚不清楚，但是最近从轨道上观察到的近红外发射率表明它们富含二氧化硅。这与以前的解释相反，后者认为富含二氧化硅的流变性太弱，无法产生海藻褶皱。我们检查了与在tessera中观察到的褶皱一致的组成范围。我们使用最高分辨率的麦哲伦雷达图像（〜100 m）和立体地形（〜1 km）在特鲁斯雷西奥·泰塞拉地区绘制褶皱图。我们使用倍距作为屈曲分析的输入，屈曲分析使用当代的干矿物流定律和模拟火成岩成分模拟幂律流变学，与最近时期金星的预测干岩石圈一致。褶皱的主波长为6–19 km，振幅为500–1,000 m，与低应变（1％–12％）一致。我们确认观察到的褶皱要求热流≥40 K / km，应变速率快于10^-16 s ^-1，比今天高。这些低应变褶皱不可能显着改变先前存在的tessera表面，因此必须通过较早的地质过程清除较旧的撞击坑。我们证明褶皱可以在干燥的地壳中形成，SiO ₂含量在48％到72％之间。干燥的长英质流变学可以解释tesserae的低发射率特征，这归因于Fe ²⁺的含量低。如果是长英质，则在以前的时代可能会通过将地表水再循环到金星地幔中而产生的含水材料的部分熔融来形成泰斯拉藻材料。