Denudation rates of the Southern Espinhaço Range, Minas Gerais, Brazil, determined by in situ-produced cosmogenic beryllium-10
Denudation rates of the Southern Espinhaço Range, Minas Gerais, Brazil, determined by in situ-produced cosmogenic beryllium-10
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巴西米纳斯吉拉斯州埃斯皮尼亚索山脉南部的剥蚀率，由原位产生的宇宙成因铍 10 决定
DOI：
10.1016/j.geomorph.2013.01.021
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发表时间：
2013
期刊：
影响因子：
3.9
通讯作者：
A. Varajão
中科院分区：
文献类型：
--
作者：
H. N. Barreto;C. Varajão;R. Braucher;D. Bourlès;A. Salgado;A. Varajão
为了调查埃斯皮尼亚索山脉南部（巴西中东部）的剥蚀率，并了解这一重要的抗性和残余地势在过去 1.38My 中是如何演变的，在三个主要区域盆地的冲积沉积物中现场测量了宇宙成因 10Be 浓度，这些盆地的底层主要由石英岩组成。将这些测量结果估计的长期剥蚀率（高达 1.38My）与影响西部（圣弗朗西斯科河）和东部（多西河和热基蒂尼奥尼亚河）盆地的剥蚀率进行了比较，这些盆地分别面向西旧金山克拉通和大西洋。对不同规模（6-970km2）流域内采集的 27 个样本进行了剥蚀率测量，并与地貌参数进行了比较。尽管地貌参数值（流域地形和平均坡度）略有不同，但北部地区确定的平均剥蚀率较低，与南部地区相似。对于南部流域，多西河流域和圣弗朗西斯科河流域的值分别为 4.91±1.01mMy−1 和 3.65±1.26mMy−1；对于北部流域来说，热基蒂尼奥尼亚河流域和圣弗朗西斯科河流域分别为 4.40±1.06mMy−1 和 3.96±0.91mMy−1。如果根据流域面积、最大海拔、流域地形、平均地形和平均坡度等地貌参数绘制，这些低剥蚀率值表明没有直接相关性。这些值表明，区域景观演化缓慢，并受到抵抗岩性的强烈控制，三个研究盆地的侵蚀率相似。
To investigate denudation rates in the southern part of the Espinhaço Range (central-eastern Brazil) and to understand how this important resistant and residual relief has evolved in the past 1.38My, cosmogenic10Be concentrations produced in situ were measured in alluvial sediments from the three main regional basins, whose substratum is composed primarily of quartzites. The long-term denudation rates (up to 1.38My) estimated from these measurements were compared with those that affect the western (São Francisco River) and eastern (Doce and Jequitinhonha Rivers) basins, which face the West San Francisco craton and the Atlantic, respectively. Denudation rates were measured in 27 samples collected in catchments of different sizes (6–970km2) and were compared with geomorphic parameters. The mean denudation rates determined in the northern part are low and similar to those determined in the southern part, despite slightly different geomorphic parameter values (catchment relief and mean slope). For the southern catchments, the values are 4.91±1.01mMy−1and 3.65±1.26mMy−1for the Doce and São Francisco River basins, respectively; for the northern catchments, they are 4.40±1.06mMy−1and 3.96±0.91mMy−1for the Jequitinhonha and São Francisco River basins, respectively. These low values of denudation rates suggest no direct correlation if plotted against geomorphic parameters such as the catchment area, maximum elevation, catchment relief, average relief and mean slope gradients. These values show that the regional landscape evolves slowly and is strongly controlled by resistant lithology, with similar erosional rates in the three studied basins.