构造活动可以改变海洋盆地的体积,因此,修改海平面,冰无关。首先让我们解释左边图片。在白垩纪构造活动是高的。从地幔物质的通量海洋山脊和高原海洋盆地的体积,减少湿草地生产全球高海平面观测地球的不同地区。在坎帕阶和Mastrichtian全球犯罪是公认的在几个地层地球的部分。z Dubicka和d Peryt(2012)研究了地层序列在波兰湿草地还显示Mastrichtian海侵阶段。他们与其他相关地层的时代。>这个海平面上升,记录在波兰东南部,可以>与识别的海侵峰值汉考克(1993);>这对应Craise Graise (¼Vijlen成员)暴露在CPL >采石场Halembaye在比利时,进而对应>低Belemnitella初级区,即,最早的马斯特里赫特统末。>汉考克(1993)指出,全球可能出现这个峰值。 He > correlated it with the Prairie Bluff Chalk on the northern margin of > the Gulf of Mexico and with strata that lie a little above the base of > the Tinton Greensand on the Atlantic coastal plain. The transgressive > peak in the earliest Late Maastrichtian was also documented in the > Sopelana section in the Basque Arc Domain in Spain (Gómez-Alday et > al., 2004), which coincides with the inoceramid extinction, the > informal definition of the Lower/Upper Maastrichtian boundary. > Moreover, a marked transgression in the middle Maastrichtian was > reported from the Southern Hemisphere by Huber and Watkins (1992) who > noted a higher diversity of keeled foraminifera, which they > interpreted as reflecting a possible transgression. Then let's focus in your question about the sea level drop. It is pretty obvious a regression happened, at least at North America. The sea level drop appears to be global too, according to Matsumoto (2002) and associated to a slowing down of global tectonic activity. > Tectono-eustasy may have been the main cause of the phenomena of > transgression-regression, but certain kinds of other tectonic > movements which affected even the so-called stable platforms were also > responsible for the phenomena. The combined effects of various causes > may have been unusual in the Cretaceous, since it was a period of > global tectonic activity. The slowing down of this activity followed > by readjustments may have been the cause of the global regression at > the end of the Cretaceous. --------------- Zofia Dubicka, Danuta Peryt (2012): "Latest Campanian and Maastrichtian palaeoenvironmental changes: Implications from an epicontinental sea (SE Poland and western Ukraine)", Cretaceous Research Volume 37, October 2012, Pages 272-284. https://doi.org/10.1016/j.cretres.2012.04.009 T.Matsumoto (2002): "Inter-regional correlation of transgressions and regressions in the Cretaceous period", Palaeogeography, Palaeoclimatology, Palaeoecology. Volume 187, Issues 1–2, 1 November 2002, Pages 35-60 https://doi.org/10.1016/S0031-0182(02)00504-7