A Milankovitch scale for Cenomanian time
A Milankovitch scale for Cenomanian time
复制标题
塞诺曼尼时间的米兰科维奇音阶
DOI：
--
复制
发表时间：
1989
期刊：
影响因子：
--
通讯作者：
A. Gale
中科院分区：
文献类型：
--
作者：
A. Gale
在盎格鲁-巴黎盆地北方的赛诺曼阶半远洋白垩层中发现了详细的旋回地层，其对比范围超过100，000平方公里。个别分米尺度的偶联可能代表岁差周期（18或23 kyr的模式），并且可以很容易地分组为平均为5的集合，表明偏心率的短周期（100 kyr）。这里介绍了该盆地的复合旋回地层学，并将其用作Cenomanian时标（20和100千年单位）的基础。由此得到的森诺曼纪的总持续时间（440万年）与最近的400 - 450万年的放射性测年结果相当吻合。的时间尺度是用来估计的长度菊石，inoceramid，和浮游有孔虫区，自生矿物（钙钛矿）的形成率，沉积速率和海侵和缺氧事件的持续时间。
A detailed cyclostratigraphy is present in the rhythmically bedded Cenomanian hemipelagic chalks of the northern Anglo-Paris Basin, which can be correlated over 100,000 km2. Individual decimetre-scale couplets probably represent the precession cycle (modes at 18 or 23 kyr), and can be readily grouped in sets averaging five, indicative of the short cycle of eccentricity (100 kyr). A composite cyclostratigraphy for the basin is presented here, and is used as the basis for a Cenomanian time-scale (20 and 100 kyr units). The total duration of the Cenomanian thus obtained (4.4 Myr) compares well with recent radiometric dates of 4.0–4.5 Myr. The time-scale is used to estimate the length of ammonite, inoceramid, and planktonic foraminiferal zones, the rates of formation of authigenic minerals (glauconite), sedimentation rates and the duration of transgressions and anoxic events.