Geophysical methods for mapping Quaternary sediment thickness: Application to the Saint-Lary basin (French Pyrenees)

IF 2 4区地球科学 Q3 GEOSCIENCES, MULTIDISCIPLINARY

Comptes Rendus Geoscience Pub Date : 2019-08-01 DOI:10.1016/j.crte.2019.07.001

Pierre Bottelin , Grégory Dufréchou , Lucia Seoane , Muriel Llubes , Bernard Monod

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引用次数: 4

Abstract

This study aims at mapping the sediment infill thickness in the Saint-Lary basin (Aure valley, French Pyrenees). For this purpose, we combine passive seismic and gravity surveys. The resonance frequencies of the sediment body are retrieved from seismic ambient measurements, while the gravimetric survey shows negative residual anomaly of about −3 mGal in the basin. Both methods reveal unexpected but consistent bedrock shape. The southern Saint-Lary basin appears deeper than its northern part, with maximal infill thickness of about 300 m and 150 m, respectively. Valley cross sections show regular and smooth “U”-shape in the southern Saint-Lary basin, in contrast to an irregular and asymmetric pattern in the northern basin. This basin shape may be related to Quaternary fluvio-glacial carving processes especially controlled by a regional fault (the Soulan fault), variations in bedrock hardness, and preferential ice flow paths.

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第四纪沉积物厚度测绘的地球物理方法:在圣拉里盆地(法国比利牛斯山脉)的应用

本研究的目的是绘制圣拉里盆地(法国比利牛斯山脉的奥雷河谷)的沉积物填充厚度。为此，我们将被动地震和重力测量结合起来。沉积体的共振频率由地震环境测量得到，而重力测量显示盆地内负残余异常约为- 3 mGal。两种方法都揭示了意想不到但一致的基岩形状。圣拉里盆地南部比北部更深，最大充填厚度分别约为300 m和150 m。圣拉里盆地南部山谷剖面呈规则、光滑的“U”型，而北部则呈不规则、不对称分布。该盆地形状可能与第四纪河流-冰川雕刻作用有关，特别是受区域断裂(苏兰断裂)控制，基岩硬度变化和优先冰流路径。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Comptes Rendus Geoscience 地学-地球科学综合

CiteScore

2.80

自引率

14.30%

发文量

审稿时长

5.9 weeks

期刊介绍： Created in 1835 by physicist François Arago, then Permanent Secretary, the journal Comptes Rendus de l''Académie des sciences allows researchers to quickly make their work known to the international scientific community. It is divided into seven titles covering the range of scientific research fields: Mathematics, Mechanics, Chemistry, Biology, Geoscience, Physics and Palevol. Each series is led by an editor-in-chief assisted by an editorial committee. Submitted articles are reviewed by two scientists with recognized competence in the field concerned. They can be notes, announcing significant new results, as well as review articles, allowing for a fine-tuning, or even proceedings of symposia and other thematic issues, under the direction of invited editors, French or foreign.