High-resolution Sequence Stratigraphy and Implications For Cretaceous Glacioeustasy of the Late Cretaceous Gallup System, New Mexico, U.S.A.
High-resolution Sequence Stratigraphy and Implications For Cretaceous Glacioeustasy of the Late Cretaceous Gallup System, New Mexico, U.S.A.
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美国新墨西哥州晚白垩世盖洛普系统的高分辨率层序地层学及其对白垩纪冰川平衡的影响
DOI：
10.2110/jsr.2019.32
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发表时间：
2019
影响因子：
2
通讯作者：
Andrew Stockford
中科院分区：
文献类型：
--
作者：
Wen Lin;J. Bhattacharya;Andrew Stockford
正确理解传统岩石地层学与层序地层学的关系是正确认识时间地层关系和盆地演化的关键。样本间距不足和基准面缺乏都是层序地层对比的难题，样本间距不足会导致“混叠”。高分辨率层序地层学分析的白垩纪盖洛普组，沉积在晚Turonian早期Coniacian，文件的高频沉积旋回性使用详细的相分析在广泛暴露的露头在新墨西哥州，美国。沿着沉积倾向露头带测量了71个沉积剖面，测量剖面之间的平均距离小于1公里。横向广泛的膨润土层，沉积在几乎水平的海床上，提供了年代控制，并作为基准，以最小的地层失真进行准确的对比。通过关键界面与详细相分析相结合，识别出12个层序，其中26个准层序组由61个准层序组成。四类海岸线轨迹量化：上升回归与加速和减速率，下降回归，海侵。各准层序组的最大岸线海进和海退分别达60 km和48 km。估计各准层序组的最大相对海平面下降和上升分别为34 m和38 m。准层序组表现为加积-加积、退积、加积-加积和退积叠加模式。这些可容纳空间序列有助于确定体系域。结果表明，已填图的砂岩舌相当于高频层序组。年代地层学分析表明，迪尔科段具有穿时性，并与不同的层序相对应。托里维奥段河流相砂岩可能为穿时沉积，部分可能为盖洛普时代。相对海平面福尔斯和上升幅度的匹配，以及缺乏构造作用的证据，表明海平面升降控制。自生过程可能在沉积过程中起作用，但不是主要的控制因素。层序、准层序组和准层序的沉积时间分别为10万年、46.2万年和19.7万年，表明米兰科维奇旋回主导的冰川-古生物旋回可能是温室时代盖洛普体系高频层序地层的关键控制因素。
Deciphering the relationships between traditional lithostratigraphy and sequence stratigraphy is the key to correctly understanding time-stratigraphic relationships and basin evolution. Both insufficient sample spacing, which induces ‘‘aliasing,’’ and lack of datums are problematic issues for sequence stratigraphic correlation. Highresolution sequence stratigraphic analysis of the Cretaceous Gallup Formation, deposited during the late Turonian to early Coniacian, documents the high-frequency depositional cyclicity using detailed facies analysis in extensively exposed outcrops in northwestern New Mexico, USA. Seventy-one sedimentological sections were measured along the depositional-dip-oriented outcrop belt, with less than 1 km average distance between measured sections. Laterally extensive bentonite layers, deposited on nearly horizontal seabeds, provide chronological control and are used as datums for accurate correlations with minimal stratigraphic distortion. Based on the integration of key bounding surfaces with detailed facies analysis, twelve stratigraphic sequences, consisting of twenty-six parasequence sets composed of sixty-one parasequences, were identified. Four classes of shoreline trajectory are quantified: ascending regressive with accelerating and decelerating rates, descending regressive, and transgressive. The maximum shoreline transgression and regression of individual parasequence sets are up to 60 km and 48 km respectively. The maximum estimated relative sea-level fall and rise of individual parasequence sets are 34 m and 38 m. Parasequence sets show aggradational–progradational, retrogradational, progradational–aggradational, and degradational stacking patterns. These accommodation successions help to define systems tracts. The results show that the previously mapped sandstone tongues are equivalent to high-frequency sequence sets. Chronostratigraphic analysis shows that the Dilco Member is diachronous and correlated to different sequences. The Torrivio Member fluvial sandstone was probably deposited diachronously, and part of it may be Gallup age. The matching magnitudes of relative sea-level falls and rises, and an absence of evidence of tectonism, suggest a eustatic control. Autogenic processes may have operated during deposition but were not the dominant controls. The estimated depositional durations of sequence, parasequence set, and parasequence are 100 kyr, 46.2 kyr, and 19.7 kyr, respectively, implying that Milankovitchcycle-dominated glacio-eustasy may be the key control on the high-frequency sequence stratigraphy of the Gallup system in greenhouse age.