History of the Cretaceous Osbourn spreading center
History of the Cretaceous Osbourn spreading center
复制标题
DOI：
10.1029/2006jb004550
复制
发表时间：
2007-04-06
影响因子：
3.9
通讯作者：
Cande, Steven C.
中科院分区：
文献类型：
--
作者：
Downey, Nathan J.;Stock, Joann M.;Cande, Steven C.
[ 1]奥斯伯恩海槽是一个化石扩散中心，在白垩纪期间将马尼希基和希库朗吉高原分开。以前的Osbourn扩张中心模型是基于槽轴附近收集的数据，因此只限制了Osbourn扩张中心在过去几个Ma的扩张历史。我们的数据集包括向北收集到的Manihiki高原的多波束数据，使我们能够检查在Osbourn扩张中心的整个活跃时期创建的海底形态，以及几个额外的多波束数据集，这些数据集提供了检查Osbourn古扩张中心和白垩纪太平洋-凤凰海岭之间关系的机会。海槽的轴向重力与其他已灭绝的中慢速扩张速率海脊的重力相似。磁场测量表明，在槽传播停止在Chron C34。深渊山的趋势表明，在奥斯伯恩扩张中心的早期历史中，扩张发生在15度-20度。这种扩张的东西向分量解释了马尼希基和希库朗吉高原的现代东西向偏移。传播旋转到2度- 5度前熄灭。深海山RMS振幅表明，扩张速率从> 7 cm/年下降到2 - 6 cm/年的全扩张速率，与海脊灭绝前2 - 6 Ma相似。我们的数据分析无法确定在减速事件之前Osbourn扩展中心的确切扩展速率。由我们的数据提供的时间限制表明，Osbourn扩展中心停止扩展之前87马或93马，这取决于是否Manihiki和Hikurangi高原裂谷在115马或121马。我们的模型解决了Osbourn传播的区域模型之间的冲突与模型的基础上槽的特点，显示在Osbourn传播中心的传播解耦太平洋凤凰传播。
[ 1] The Osbourn Trough is a fossil spreading center that rifted apart the Manihiki and Hikurangi Plateaus during Cretaceous time. Previous models of the Osbourn spreading center are based on data collected near the trough axis, and therefore only constrain the history of the Osbourn spreading center during the last few Ma of spreading. Our data set includes multibeam data collected northward to the Manihiki Plateau, allowing us to examine seafloor morphology created during the entire active period of the Osbourn spreading center, as well as several additional multibeam data sets that provide the opportunity to examine the relationship between the Osbourn paleospreading center and the Cretaceous Pacific-Phoenix ridge. The axial gravity of the trough is similar to the gravity found at other extinct slow-intermediate spreading rate ridges. Magnetic field measurements indicate that spreading at the trough ceased during Chron C34. Abyssal-hill trends indicate that spreading during the early history of the Osbourn spreading center occurred at 15 degrees- 20 degrees. The east-west component of this spreading explains the modern east-west offset of the Manihiki and Hikurangi Plateaus. Spreading rotated to 2 degrees - 5 degrees prior to extinction. Abyssal-hill RMS amplitudes show that a decrease in spreading rate, from > 7 cm/yr to 2 - 6 cm/yr full-spreading rate, occurred similar to 2 - 6 Ma prior to ridge extinction. Our data analysis is unable to determine the exact spreading rate of the Osbourn spreading center prior to the slowing event. The temporal constraints provided by our data show that the Osbourn spreading center ceased spreading prior to 87 Ma or 93 Ma, depending on whether the Manihiki and Hikurangi Plateaus rifted at 115 Ma or 121 Ma. Our model resolves the conflict between regional models of Osbourn spreading with models based on trough characteristics by showing that spreading at the Osbourn spreading center was decoupled from Pacific-Phoenix spreading.