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Lacustrine deposits form most of the sedimentary record accumulated throughout the Miocene in the northern part of the Teruel Graben, a landlocked basin situated in NE Spain. Three main stratigraphic units (Units I-Ill ) spanning Late Vallesian to Late Turolian in age, are distinguished in the area. The two former units comprise mainly carbonate lacustrine deposits that were deposited in a palustrine or a more permanent but shallow lacustrine setting, the latter being related mainly to periods of lake expansion under more humid and cooler climatic conditions. In contrast, deposition of Unit Ill, characterised by gypsiferous lacustrine sediments in central parts of the basin, reflects the influence of source rocks of evaporitic nature (Upper Triassic formations) that were emplaced by diapiric uplift in the eastern margin during the Middle Turolian. Carbonate lake sediments belonging to Units I and 11 consist of four main lithofacies associations: (a) distal-alluvial lake margin deposits; (b) lacustrine carbonates and pedogenically modified lacustrine carbonates; (c) carbonate fill channels; and (d ) organic-rich marlstone and carbonate (marshes).Lithofacies association (a) shows typically a sequential arrangement formed, from bottom to top, of red mudstone, carbonate palaeosols and biomicrite beds (sequence type la). These sequences are interpreted as a result of slow but continuous aggradation of the f100dplain areas and subsequent rise of the water table, probably reflecting equilibrium between subsidence and sedimentation. Lithofacies association (b) consisting of biomicrite beds passing upward into palaeosols (sequence type I b) is thought to be caused by marked pulses of tectonic subsidence that created the accommodation space required for fast development of a carbonate lake. Carbonate fill channels, showing erosive lower surfaces dig out on previous channels, marsh deposits and/or lacustrine carbonates, exhibit well-developed prismatic structure at their bed tops. The sequential arrangement suggests similar tectonic constrains than the envisaged for lithofacies lb. The comparison of depositional styles of the lake systems with the palaeoclimatic evolutionary pattern of the basin throughout the Miocene indicates that the combined effect of tectonism, climate and source rock played a major role in the stratigraphic framework of the basin during this period.

Contents 1. Introduction 103 2. The Sedimentary (Ancient) Record of Palustrine Carbonates 105 2.1. The primary lacustrine mud 105 2.2. Carbonate palustrine facies in the sedimentary record 107 2.3. Genetic aspects of the palustrine carbonate facies 113 3. Wetlands: The Recent Analogues for Ancient Palustrine Environments? 115 4. Environmental Controls on Palustrine Deposition 119 5. Conclusions 125 126 References 126 Ã Corresponding author.

Geochemical signals from speleothems are commonly used in the investigation of palaeoenvironments. In most cases. however. liule aUention is paid to whether or not these signals are primary or altered by diagenesis. The speleothems of the Castañar Cave (Cáceres. Spain). which are initially formed of calcite or aragonite. have undergone a variety of meteoric diagenetic processes such as micritization and neomorphism (inversion Where inversion took place. some secondary calcites after the aragonite show preserved aragonite. whereas others do not. The secondary calcites without aragonite relics show isotopic values slightly higher than those of the primary ca1cite due to the inheritance of the aragonite signa!. Where aragonite relics are preserved. the isotopic signatures are very similar to those of the aragonite micrite. In addition. the stable isotopic values and Sr and Mg contents of the speleothems became also modified by micritization andjor inversion. These diagenetic processes were driven by the changes in composition of the cave waters over time and space. but also. in the case of aragonite. by its initial unstable mineralogy. The present results highlight how important diagenesis is in caves and how the initial features of cave minerals may be lost. These changes alter the geochemical signals shown by speleothems. which may have an impact on the interpretation of the results obtained in palaeoenvironmental studies.

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