曾经被认为非常均质的海岭玄武岩实际上是很不均质的,其主要原因是上地幔的不均质性以及羽状地幔流的存在。然而,由于海岭玄武岩是在上地幔形成后经历了复杂过程喷发的,所以仅靠海岭玄武岩本身很难确定它在地幔中的变化过程是其不均质性的原因。自1947年利用RV Atlantis号进行海底采样以来,主要在大西洋中央海岭、印度洋中央海岭等地区发现了大量的超镁铁岩(以橄榄岩为主),从而知道了超镁铁岩在洋底广泛存在 Ridge basalts, once thought to be very homogeneous, are in fact very heterogeneous, mainly due to the heterogeneity of the upper mantle and the presence of pinnate mantle flow. However, since Ridge Basalt is experiencing a complicated process of eruption after the formation of the upper mantle, it is difficult to determine by Ridge Basalt alone how its variation in the mantle is its heterogeneity. Since the seabed sampling was carried out using the RV Atlantis in 1947, a large number of ultramafic rocks (dominated by peridotites) have been found, mainly in the central midline of the Atlantic Ocean and the central Indian Ocean Ridge, so that it is known that ultramafic rocks are widely distributed in the ocean floor exist