A sequence stratigraphic framework predicts that time averaging and hiatus durations will be long at times of fastest sea-level rise. This prediction does not necessarily apply to environments where carbonate production keeps up with sea-level rise and where undetected hiatuses decouple short-term from long-term sedimentation rates. The taphonomic clock, however, which measures the residence time of skeletal particles in the mixed layer, can estimate the duration of hiatuses if the rate of skeletal alteration is slow and if skeletal particles endure long-term exposure in the mixed layer. Here, time averaging is calibrated by using evidence from alteration of bivalves in a metre-scale Holocene sequence in the Adriatic Sea. In this sequence, transgressive molluscan lags, a maximum-flooding zone shell bed with bivalves, and highstand bryomol assemblages were all deposited under similar long-term sedimentation rates (ca 0.01 to 0.03 cm year⁻¹) and exhibit millennial time averaging. Median ages of valves stained by pyrite and cemented by high-magnesium calcitic micritic envelopes exceeding ca 1000 years indicate that: (i) these authigenic processes are slow in subsurface zones with reducing conditions (with prolonged sulphate reduction and carbonate ions sourced from dissolved shells in the surface zones); and (ii) subsurface micrite precipitation prolongs the disintegration half-lives of valves exhumed to surface zones from decades to millennia. The high abundance of stained valves, valves with micrite envelopes, and valves with composite alteration (encrusters and borers colonizing stained and cemented grains) thus identifies hiatuses and skeletal concentrations time-averaged to >1000 years. The upcore decrease in abundance of valves with composite alteration, coupled with temporally-constant long-term sedimentation rates and time averaging, indicates that a temporal decline in sediment exhumation was compensated by a decline in burial of skeletal carbonate produced by molluscs.

中文翻译：

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推断高频沉积层序地层记录中的时间平均和中断持续时间

序列地层框架预测，在海平面上升最快的时候，时间平均和中断持续时间会很长。这一预测不一定适用于碳酸盐产量与海平面上升保持同步的环境，以及未检测到的中断将短期与长期沉降速率脱钩的环境。然而，测量骨骼颗粒在混合层中的停留时间的埋藏钟可以估计如果骨骼改变的速度很慢并且骨骼颗粒在混合层中长期暴露，则可以估计中断的持续时间。在这里，时间平均是通过使用亚得里亚海米尺度全新世序列中双壳贝类变化的证据来校准的。在这个序列中，海进的软体动物滞后，最大泛滥区的贝壳床有双壳类，ca 0.01 to 0.03 cm year ^-1 ) 并表现出千年时间平均。黄铁矿染色和高镁方解石泥晶包膜胶结的瓣膜的中位年龄超过ca1000 年表明：（i）这些自生过程在具有还原条件的地下区域中是缓慢的（硫酸盐还原时间延长，并且碳酸盐离子来源于表面区域中溶解的壳）；(ii) 地下微晶沉淀将挖掘到地表区域的阀门的分解半衰期从几十年延长到几千年。大量的染色瓣膜、具有微晶包膜的瓣膜和具有复合蚀变的瓣膜（结壳和蛀虫在染色和胶结颗粒上定殖）因此确定了平均时间超过 1000 年的裂孔和骨骼浓度。具有复合改变的瓣膜丰度的上部减少，加上时间恒定的长期沉降速率和时间平均，