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首页> 外文学位 >Aspects of the thermal history of the eastern margin of Canada based on apatite fission track and (uranium-thorium)/helium thermochronology.
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Aspects of the thermal history of the eastern margin of Canada based on apatite fission track and (uranium-thorium)/helium thermochronology.

机译：基于磷灰石裂变径迹和（铀-or）/氦热年代学的加拿大东缘热史方面。

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摘要

Apatite fission track (FT) and (U-Th)/He thermochronology and vitrinite reflectance (Ro) are used to study cooling and inferred denudation in 3 areas; (1) the Triassic-Early Jurassic Fundy Basin, a failed rift subsequently exhumed as part of the onshore southern Canadian Atlantic margin; (2) the Late Paleozoic-Mesozoic Sverdrup Basin, an inverted intracratonic failed rift that developed following the Ellesmerian Orogeny in the Canadian Arctic Archipelago; and (3) the Sverdrup Basin sediment source region around Nares Strait-Kane Basin-Smith Sound, an area affected by the Paleogene Eurekan Orogeny.; A limitation of the Laslett et al. (1987) FT annealing model is elucidated, and I demonstrate that low-temperature estimates from that model are inconsistent with measured (U-Th)/He ages. An initial model track length of 15 mum eliminates unrealistic late-stage FT model cooling and produces temperature histories compatible with (U-Th)/He data. The importance of measuring 147Sm in (U-Th)/He-dated samples is also demonstrated. Up to 20% of the radiogenic 4He in my samples was 147Sm-derived. Failure to consider this 4He source would cause considerable overestimation of (U-Th)/He ages.; (U-Th)/He data and FT models for the southern Canadian Atlantic margin demonstrate that following the onset of Atlantic rifting, the region experienced rapid Jurassic exhumational cooling. FT and Ro data from the Sverdrup Basin demonstrate substantial cooling from inversion during the Eurekan Orogeny. Many thrust faults drilled during hydrocarbon exploration in the basin in the 1970's were active during the Eurekan Orogeny, which post-dates primary hydrocarbon maturation and migration, and are therefore poor targets. (U-Th)/He data and FT models for the Kane Basin-Smith Sound region suggest the complex thermal history results from at least 3 tectonic influences; (1) Late Paleozoic-Early Mesozoic regional exhumation related to Sverdrup Basin development; (2) Late Cretaceous cooling of rift flanks following the onset of Labrador Sea-Baffin Bay rifting; and (3) Paleocene inversion related to Eurekan convergence between Ellesmere Island and Greenland. FT ages related to the orogeny from fault-bounded basins near Nares Strait are older than ages from thrust fault hanging walls in central Ellesmere Island, suggesting cooling progressed east-west.
机译：磷灰石裂变径迹（FT）和（U-Th）/ He热年代学和镜质反射率（Ro）用于研究3个区域的冷却和推断剥蚀。 （1）三叠纪-早侏罗纪底盆盆地，一个破裂的裂谷随后被挖掘出，作为加拿大南部大西洋沿岸边缘的一部分； （2）晚古生代-中生代斯维尔德鲁普盆地，是一个反向克拉通破裂的裂谷，是在加拿大北极群岛的埃尔斯梅里造山运动之后发展而来的； （3）受古近纪尤里坎造山带影响的纳雷斯海峡-凯恩盆地-史密斯湾附近的斯维尔德鲁普盆地沉积物源区。 Laslett等人的局限性。 （1987）阐明了FT退火模型，我证明了该模型的低温估算值与实测（U-Th）/ He年龄不一致。初始模型轨道长度为15毫米，消除了不切实际的后期FT模型冷却，并产生了与（U-Th）/ He数据兼容的温度历史记录。还证明了在（U-Th）/ He约会样品中测量147Sm的重要性。在我的样本中，多达20％的放射源4He来自147Sm。不考虑这4He辐射源将导致（U-Th）/ He年龄的高估。 （U-Th）/ He数据和加拿大南部大西洋边缘的FT模型表明，随着大西洋裂谷的爆发，该地区经历了侏罗纪的快速尸体降温。来自Sverdrup盆地的FT和Ro数据表明，在Eurekan造山运动中，反转产生了明显的降温作用。在1970年代该盆地的油气勘探期间钻出的许多逆冲断层在尤里坎造山运动期间是活跃的，该时期早于原始油气成熟和运移，因此是较差的目标。凯恩盆地-史密斯声音地区的（U-Th）/ He数据和FT模型表明，复杂的热历史是至少受3个构造影响的结果。 （1）与斯维尔德鲁普盆地发育有关的晚古生代-早中生代区域发掘； （2）拉布拉多海-巴芬湾裂谷开始后，白垩纪裂陷侧面冷却； （3）古新世反演与埃尔斯米尔岛和格陵兰岛的尤里坎汇合有关。与纳雷斯海峡附近断层界定盆地的造山运动有关的FT年龄比埃尔斯米尔岛中部逆冲断层悬挂壁的年龄大，这表明东西向逐渐冷却。

著录项

  • 作者

    Grist, Alexander Michael.;

  • 作者单位

    Dalhousie University (Canada).;

  • 授予单位 Dalhousie University (Canada).;
  • 学科 Geology.
  • 学位 Ph.D.
  • 年度 2004
  • 页码 418 p.
  • 总页数 418
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 地质学;
  • 关键词

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