Physical weathering of carbonate host-rock by precipitation of soluble salts in caves: A case study in El Orón-Arco Cave (Region of Murcia, SE Spain)
Physical weathering of carbonate host-rock by precipitation of soluble salts in caves: A case study in El Orón-Arco Cave (Region of Murcia, SE Spain)
复制标题
洞穴中可溶盐沉淀对碳酸盐主岩的物理风化：El Orón-Arco 洞穴（西班牙东南部穆尔西亚地区）的案例研究
DOI：
10.1016/j.chemgeo.2019.05.010
复制
发表时间：
2019
期刊：
影响因子：
3.9
通讯作者：
Gázquez F
中科院分区：
文献类型：
--
作者：
Gázquez F
在潜水或渗流条件下，碳酸盐岩母岩被淡水溶解是洞穴形成的最常见机制;然而，盐溶液通过碳酸盐物质的循环和可溶性盐的沉淀也可能发挥重要作用。本文研究了西班牙东南部卡塔赫纳El Orón-Arco洞穴石膏洞穴中流体包裹体的稳定同位素组成（硫酸盐的δ 18 O和δ 34 S，构造结合石膏水化水的δ 18 O和δD以及87 Sr/86 Sr）和盐度。我们认为，碳酸盐岩的物理风化是由可溶性海盐（主要是石膏和岩盐）的沉淀驱动的，这个过程控制了洞穴的近期地貌演化。三叠纪碳酸盐岩主岩显示出盐风化的明显证据，包括基岩裂缝中的石膏/岩盐填充物、碳酸盐的机械剥落以及岩石碎片的分离，这些岩石碎片导致形成洞穴空隙和未分类碎石堆的原位堆积。石膏硫酸盐的硫、氧同位素（3.0‰ < δ 18 O < 11.6‰和16.7‰ < δ 34 S < 20.7‰）普遍低于现代海水硫酸盐，表明其来源于贫34 S源（即黄铁矿氧化）。与纯海水蒸发至石膏饱和度的预期值相比，石膏水化水的δ 18 O和δD相对较低，这表明石膏沉淀涉及次生硫酸钙来源或来自前几个阶段的石膏再循环，沿着海水和大气降水渗入洞穴的混合。石膏中的87 Sr/86 Sr值介于现代海水和三叠纪碳酸盐岩之间，这是由于溶液与基岩之间的相互作用。洞穴积土形成溶液的盐度相对较高（13.2 ± 3.2 wt% eq. NaCl）与由蒸发的微咸溶液形成的石膏（即约4-8重量%当量）相比，NaCl），并表明在二次石膏沉淀之前，早期碳酸盐岩的溶解。这种与盐水循环和碳酸盐矿物沉淀有关的成洞机制可能在其他沿海洞穴中很常见。
The dissolution of carbonate host-rock by freshwater in phreatic or vadose conditions is the most common mechanism for the formation of caves; however, circulation of saline solutions through carbonate materials and precipitation of soluble salts may also play an important role. We studied the stable isotope composition (δ18O and δ34S of sulfate, δ18O and δD of structurally-bound gypsum hydration water and87Sr/86Sr) and salinity of fluid inclusions in gypsum speleothems found in El Orón-Arco Cave (Cartagena, SE Spain). We suggest that physical weathering of carbonate host-rock was driven by precipitation of soluble sea-salts (mostly gypsum and halite), and this process controlled the recent geomorphological evolution of the cave. The Triassic carbonate host-rock shows clear evidence for salt weathering, including gypsum/halite infillings in cracks of the bedrock, mechanical spalling of the carbonate, and detachment of rock fragments that lead to the formation cave voids and in-situ accumulations of piles of unsorted rubble. Sulfur and oxygen isotopes of gypsum sulfate (3.0‰ < δ18O < 11.6‰ and 16.7‰ < δ34S < 20.7‰) are generally lower than modern seawater sulfate and suggest contributions from a34S-depleted source (i.e. oxidation of pyrite). The δ18O and δD of gypsum hydration water are relatively low compared to expected values for the evaporation of pure seawater to gypsum saturation, suggesting that gypsum precipitation involved a secondary calcium-sulfate source or recycling of gypsum from previous stages, along with mixing of seawater and meteoric water seepage to the cave. The87Sr/86Sr in gypsum shows intermediate values between modern seawater and Triassic carbonate values because of interaction between the solution and the bedrock. The salinities of the speleothem-forming solutions are relatively high (13.2 ± 3.2 wt% eq. NaCl) compared to gypsum formed from evaporated brackish solutions (i.e. ~4–8 wt% eq. NaCl) and indicate dissolution of earlier evaporites before secondary gypsum precipitation. This cave-forming mechanism, which is related to saline water circulation and precipitation of evaporitic minerals, may be common in other coastal caves.
登录
查看更多内容
稀溶液中石膏成岩作用的同位素记录：天然盐沼的观察和实验
影响因子：
3.9
作者：
C. Pierre
通讯作者：
C. Pierre
南极洲维多利亚地泰勒干谷的洞穴风化
影响因子：
64.8
作者：
M. Prebble
通讯作者：
M. Prebble
用于 XRD 分析的振动样品架，只需最少的样品制备
DOI：
--
发表时间：
2005
期刊：
影响因子：
--
作者：
P. Sarrazin;S. Chipera;D. Bish;D. Blake;D. Vaniman
通讯作者：
D. Vaniman
石膏洞穴中的洞穴矿物和洞穴矿物
DOI：
--
发表时间：
1996
期刊：
影响因子：
--
作者：
P. Forti
通讯作者：
P. Forti
影响因子：
5
作者：
Gazquez, Fernando;Evans, Nicholas P.;Hodell, David A.
通讯作者：
Hodell, David A.