At the Galapagos triple junction in the equatorial Pacific Ocean, the Cocos‐Nazca spreading center does not meet the East Pacific Rise (EPR) but, instead, rifts into 0.4 Myr‐old lithosphere on the EPR flank. Westward propagation of Cocos‐Nazca spreading forms the V‐shaped Galapagos gore. Since ~1.4 Ma, opening at the active gore tip has been within the Cocos‐Galapagos microplate spreading regime. In this paper, bathymetry, magnetic, and gravity data collected over the first 400 km east of the gore tip are used to examine rifting of young lithosphere and transition to magmatic spreading segments. From inception, the axis shows structural segmentation consisting of rifted basins whose bounding faults eventually mark the gore edges. Rifting progresses to magmatic spreading over the first three segments (s1–s3), which open between Cocos‐Galapagos microplate at the presently slow rates of ~19–29 mm/year. Segments s4–s9 originated in the faster‐spreading (~48 mm/year) Cocos‐Nazca regime, and well‐defined magnetic anomalies and abyssal hill fabric close to the gore edges show the transition to full magmatic spreading was more rapid than at present time. Magnetic lineations show a 20% increase in the Cocos‐Nazca spreading rate after 1.1 Ma. The near‐axis Mantle Bouguer gravity anomaly decreases eastward and becomes more circular, suggesting mantle upwelling, increasing temperatures, and perhaps progression to a developed melt supply beneath segments. Westward propagation of individual Cocos‐Nazca segments is common with rates ranging between 12 and 54 mm/year. Segment lengths and lateral offsets between segments increase, in general, with distance from the tip of the gore.

中文翻译：

---

在向西传播的科科斯纳斯卡传播中心的尖端，海底传播的演变

在赤道太平洋的加拉帕戈斯三重交界处，科科斯·纳斯卡扩散中心未达到东太平洋上升（EPR），而是在EPR侧缘裂入0.4迈尔古岩石圈。科科斯纳斯卡传播的向西传播形成了V形的加拉帕戈斯戈尔。从约1.4 Ma开始，活跃的孔口尖端一直处于Cocos-Galapagos微孔板撒布范围内。在本文中，使用了在戈尔山顶以东前400公里处收集的测深，磁和重力数据，来检查年轻岩石圈的裂谷和过渡到岩浆扩展段。从一开始，该轴就显示出由裂陷盆地组成的结构分段，这些盆地的边界断层最终标记了戈尔边缘。在前三段（s1-s3），裂谷作用逐渐发展到岩浆扩散，在Cocos-Galapagos微孔板之间以目前每年约19-29 mm的慢速打开。s4–s9段起源于传播速度较快（约48毫米/年）的Cocos-Nazca政权，并且清晰的磁异常和靠近戈尔边缘的深海丘陵构造表明，向全岩浆扩散的过渡比目前更快时间。磁力线显示，在1.1 Ma之后，Cocos-Nazca扩散速率增加了20％。近轴地幔布格重力异常向东递减，并变得更圆，这表明地幔上升流，温度升高，并可能发展为分段下方发达的熔体供应。科科斯纳斯卡各段向西传播的情况很普遍，速率在每年12到54毫米之间。通常，段长度和段之间的横向偏移会增加，