Prolonged high relief in the northern Cordilleran orogenic front during middle and late Eocene extension based on stable isotope paleoaltimetry
Prolonged high relief in the northern Cordilleran orogenic front during middle and late Eocene extension based on stable isotope paleoaltimetry
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基于稳定同位素古测温的中、晚始新世伸展过程中北科迪勒拉造山锋的长期高地势
DOI：
10.1016/j.epsl.2016.10.038
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发表时间：
2017
影响因子：
5.3
通讯作者：
Dettman, David L.
中科院分区：
文献类型：
--
作者：
Fan, Majie;Constenius, Kurt N.;Dettman, David L.
白垩纪晚期-古近纪收缩和随后的伸展构造期间北美科迪勒拉造山带的古海拔和大小仍然是个谜。我们利用基谢恩盆地未改变的软体动物化石和古土壤碳酸盐的氧同位素组成，对始新世中晚期北科迪勒拉造山锋的古地貌进行了新的估计。基谢恩盆地东部以几座山脉为界，是始新世中期至中新世早期科迪勒拉造山带塌陷期间形成的半地堑。这些软体动物类群包括三个同域类群，它们与潮湿的热带、半干旱的亚热带和温带环境有亲缘关系。我们重建的始新世中晚期地表水δ18O值在-19.8‰和-6.3‰（VSMOW）之间变化。古环境和地表水δ18O值的巨大差异表明Kishenehn盆地的流域处于不同的海拔高度。根据瑞利凝结模型和利用同位素全球气候模型对始新世降水同位素值的预测，估计盆地与周围山脉之间的古地势约为 4 公里，盆地底部高度 <1.5 公里。这种高地势和高浮雕古地理表明，科迪勒拉造山锋在始新世重力塌陷之前海拔至少达到了4公里，地壳厚度可能已达到55公里以上。我们将始新世高地貌的维持归因于继承的厚地壳、地幔上升引起的热隆起以及下部岩石圈或大洋板块去除引起的均衡隆起的组合。
The paleoelevation and size of the North America Cordilleran orogen during the late Cretaceous–Paleogene contractional and subsequent extensional tectonics remain enigmatic. We present new estimates of paleorelief of the northern Cordilleran orogenic front during the middle and late Eocene using oxygen isotope compositions of unaltered molluscan fossils and paleosol carbonates in the Kishenehn basin. Bounded by several mountains ranges to the east, the Kishenehn basin was a half graben developed during middle Eocene to early Miocene collapse of the Cordilleran orogen. These mollusk taxa include three sympatric groups with affinities to wet tropical, semi-arid subtropical, and temperate environments. Our reconstructed surface waterδ18O values vary between −19.8‰ and −6.3‰ (VSMOW) during the middle and late Eocene. The large differences in paleoenvironments and surface waterδ18O values suggest that the catchment of the Kishenehn basin was at variable elevation. The estimated paleorelief between the basin and the surrounding mountains, based on both Rayleigh condensation model and predictions of Eocene precipitation isotope values using an isotope-enabled global climate model, is ∼4 km, and the basin floor was <1.5 km high. This high topography and high relief paleogeography suggest that the Cordilleran orogenic front reached an elevation of at least 4 km, and the crust thickness may have reached more than 55 km before Eocene gravitational collapse. We attribute the maintenance of high Eocene topography to the combination of an inherited thick crust, thermal uplift caused by mantle upwelling, and isostatic uplift caused by removing lower lithosphere or oceanic slab.
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影响因子：
5.8
作者：
K. Snell;B. Thrasher;J. Eiler;P. Koch;L. Sloan;N. Tabor
通讯作者：
K. Snell;B. Thrasher;J. Eiler;P. Koch;L. Sloan;N. Tabor
蒙大拿州中福克弗拉特黑德河始新世 Kishenehn 地层的陆地和水生软体动物
DOI：
--
发表时间：
2014
期刊：
影响因子：
--
作者：
H. G. Pierce;K. Constenius
通讯作者：
K. Constenius
美国蒙大拿州西北部科迪勒拉前陆盆地系统的演化
DOI：
--
发表时间：
2011
期刊：
影响因子：
--
作者：
F. Fuentes;P. DeCelles;K. Constenius;G. Gehrels
通讯作者：
G. Gehrels
以及服务中新生代伸展的北美科迪勒拉构造岩浆演化
DOI：
--
发表时间：
2007
期刊：
影响因子：
--
作者：
B. Wernicke;R. L. Christiansen;P. England;L. J. Sonder
通讯作者：
L. J. Sonder
DOI：
--
发表时间：
2002
期刊：
影响因子：
--
作者：
P. Haeussler;D. Bradley;R. Wells;Martin L. Miller
通讯作者：
Martin L. Miller