Aspects of Cenozoic stratigraphy and paleoceanography of the labrador sea and baffin bay
Aspects of Cenozoic stratigraphy and paleoceanography of the labrador sea and baffin bay
复制标题
拉布拉多海和巴芬湾新生代地层学和古海洋学方面
DOI：
10.1016/0031-0182(80)90061-9
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发表时间：
1980
期刊：
影响因子：
--
通讯作者：
S. P. Srivastava
中科院分区：
文献类型：
--
作者：
F. Gradstein;S. P. Srivastava
古地理重建显示，在坎帕尼亚/马斯特里赫特时期至始新世，拉布拉多海南部和古新世/始新世，拉布拉多海北方有明显的开放。巴芬湾在始新世开放，但那里的运动可能主要是平移的。拉布拉多陆棚威尔斯微古生物研究表明，最新一轮始新世广泛海侵与拉布拉多海的开启阶段相吻合。最深（半深海）的条件发生在始新世。一个广泛的陆架再生发生在渐新世，可能加剧了海平面下降。陆架沉积速率普遍较高，超过10厘米/1000年，因为马斯特里赫特时间，除了局部在第三纪中期，当很少或根本没有沉积发生。拉布拉多大陆架地区和邻近的陆地在新近纪（晚期）经历了新的构造活动，很可能早在Campanian-Maestrichtian时期就形成了连接大西洋和北冰洋的海峡，其表面环流朝向北极。暖温水团浮游有孔虫的主要入侵发生在马斯特里赫特期和始新世早中期。后者与使徒早-中始新世北大西洋气候最佳，并与早-中始新世暖温无脊椎动物和脊椎动物遗骸在加拿大北极的发现。从北极到大西洋的地表环流的恢复发生在中新世晚期-上新世中期，当时拉布拉多寒流沿着加拿大大西洋边缘形成。
Paleogeographic reconstruction show significant opening of the southern Labrador Sea in Campanian/Maestrichtian to Eocene time and of the northern Labrador Sea in Paleocene/Eocene time. Baffin Bay opened in Eocene time, but motion there probably was largely translational. Micropaleontological studies of Labrador Shelf wells show that the latest Cretaceous—Eocene widespread transgression coincides with the opening phase of the Labrador Sea. Deepest (bathyal) conditions occurred in the Eocene. A broad shelf regresion occurred in the Oligocene, probably accentuated by eustatic sea-level lowering. Shelf sedimentation rates were generally high, in excess of 10 cm/1000 yr, since Maestrichtian time, except locally in the mid-Tertiary, when little or no sedimentation took place. The Labrador Shelf region and adjacent land has undergone renewed tectonic activity in (late) Neogene time.It is likely that a sea strait linking the Atlantic and Arctic Oceans became established as early as Campanian—Maestrichtian time, with surface circulation toward the Arctic. Principal incursions of warm-temperature watermass planktonic foraminifers took place in Maestrichtian and Early—Middle Eocene times. The latter correlates with apostulated Early—Middle Eocene North Atlantic Ocean climatic optimum, and with the findings of Early—Middle Eocene warm-temperature invertebrate and vertebrate remains in the Canadian Arctic. Reversal of surface circulation from the Arctic to the Atlantic occurred in the Late Miocene—Middle Pliocene, when the cold Labrador current became established along the Canadian Atlantic margin.