Facies stacking patterns and stratigraphic relationships resulting from the interaction of fluvial and wave processes, along with the paleoshoreline orientation and key surfaces, are essential to understand the temporal changes in the rate of change of accommodation space (A) versus sediment supply rate (S). High-frequency sea-level fluctuations in deltaic systems are controlled by changing accommodation and accumulation, which are explained mainly by autocyclic or allocyclic mechanisms. In deltaic systems, changes in the A/S ratio can be showed by significant variations of the internal facies architecture and the external morphology of the delta complex. These criteria have been used to investigate the relationship between autocyclic and allocyclic processes on the architectural evolution of a mixed river- and wave-influenced asymmetrical delta during the Lower-to-Middle Ordovician in the southwest Central Iberian Zone, in Portugal. Relying on the sedimentary and ichnological characteristics, the herein defined Penha Garcia Formation is classified into two main groups of facies associations, which are interpreted as deposited in a mixed asymmetrical delta with a trend of along-strike variations between wave-dominated strandplain (updrift) and river-dominated deltaic settings (downdrift). The vertical stacking arrangements of parasequences led to the identification of five depositional phases (I to V). Detailed analysis of geometry and internal architecture of the depositional phases along depositional strike shows a highly variable number of shallowing-upward cycles and facies thicknesses/heterogeneity on the updrift and downdrift side due to changes in rates of accumulation and hydrodynamic processes. The stratigraphic architectural style of the depositional phases I to V, and the trend of the total regressive ascending shoreline trajectory, are evidences that the deposition of the Penha Garcia Formation likely took place under an increasing rate of accommodation due to long-term relative sea-level rise (allocyclic), and high subsidence rates coupled with an increase in sediment supply, which could have been locally amplified by compaction of the prodelta-related muddy beds (autocyclic). This study suggests that in evaluating the autocyclic mechanisms on deltaic processes in short-time scales, there is a remarkable difference in terms of its impact on the internal variability of the depositional phases, both in the updrift and downdrift regions of mixed-influenced asymmetrical deltas. The most important reasons for the different effects of autocyclic mechanisms can be related to facies-dependent differential compaction or local changes in subsidence pattern, differences in the proximity to the distributary channel system, and differences in the influence of intrinsic processes of storm and wave reworking (wave-sweeping mechanisms).

由河流和波浪过程的相互作用以及古海岸线的方向和关键面的相互作用而产生的相堆积模式和地层关系，对于了解适应空间变化率（A）与沉积物供应率（S）的时间变化是必不可少的。）。三角洲系统中的高频海平面波动是通过改变适应性和累积性来控制的，这主要是通过自循环或同周循环机制来解释的。在三角洲系统中，A / S比的变化可以通过三角洲内部构造和外部形态的显着变化来显示。这些标准已被用来研究葡萄牙西南伊比利亚中南部奥陶纪下，中奥陶纪混合河流和波浪影响的不对称三角洲在建筑演化过程中的自循环过程和同位循环过程之间的关系。根据沉积和岩石学特征，本文定义的Penha Garcia地层被分为两大类：它们被解释为沉积在一个混合的非对称三角洲中，在以波浪为主的平原地区（上升漂流）和以河流为主的三角洲地区（下降漂流）之间存在沿走向变化的趋势。副序列的垂直堆叠排列导致了五个沉积相（Ⅰ至Ⅴ）的识别。沿沉积走向对沉积相的几何结构和内部构造进行的详细分析显示，由于堆积速率和流体动力学过程的变化，浅向上-向上的循环次数和上，下漂移侧的相厚度/非均质性变化很大。沉积阶段I至V的地层建筑风格以及总回归上升海岸线轨迹的趋势，有证据表明，Penha Garcia地层的沉积可能是由于长期相对海平面上升（成环），高沉降率和沉积物供应量增加（可能是局部的）而在适应率增加下发生的。通过压实与prodelta相关的泥床（自循环）而放大。这项研究表明，在短期尺度上评估三角洲过程的自旋机制时，在混合影响的非对称三角洲的上，下漂移区，它对沉积相内部变异性的影响存在显着差异。 。自循环机制作用不同的最重要原因可能与相依赖的压实压实或沉降模式的局部变化有关，