RT Journal Article
T1 Sedimentology and geochemistry of carbonates fromlacustrine sequences in the Madrid Basin, central Spain
A1 Calvo Sorando, José Pedro
A1 Jones, B.F.
A1 Bustillo Revuelta, Manuel
A1 Fort González, Rafael
A1 Alonso Zarza, Ana María
A1 Kendall, C.
AB Lacustrine and alluvial carbonate facies have been investigated in Middle Miocene successions of the western side of the Madrid Basin in order to evaluate paleoenvironments in which carbonates formed. Carbonate facies are varied and include: ( 1) calcrete and dolocrete; (2) pond deposits; (3) lake margin dolostone; (4) mudflat carbonate; and (5) open-lake carbonate facies. The dominant mineralogy of these is dolomite and/or low-Mg calcite. No high-Mg calcite or aragonite have been detected in any sample.  ð18 O- and  ð13 C-values range from - 8.20 to - 1.80‰ PDB and - 10.25 to -0.70‰ PBD, respectively. More negative 8 18 O- and 8 13 C-values correspond to predominantly calcite calcretes and to carbonate deposited in ponds at the foot of arkosic alluvium. Higher  ð18 O-values are from both lacustrine carbonate and dolocrete. This latter lithofacies has strong geochemical similarities to dolostones deposited in a lake margin environment. Mudflat carbonate, deposited on shallow platforms subject to lake water oscillation, shows great heterogeneity in both stable isotope value and trace-element content. The mineralogy of these carbonates is dominated by calcite and the limestones contain molds of gypsum. Occurrence of calcitized dolomite textures in these facies suggests the influence of fresher water during expanding lacustrine cycles or further interaction with less saline groundwater. Trace-element contents are considered to be potential indicators of the different carbonate facies types, thus aiding the paleoenvironmental interpretation. However, discrimination among carbonate facies on the basis of trace-element contents appears to be dependent on the statistical method utilized for treatment of data. More information is needed to ascertain their use as paleoenvironmental indicators.
PB Elsevier Science B.V., Amsterdam.
SN 0009-2541
YR 1995
FD 1995
LK https://hdl.handle.net/20.500.14352/60427
UL https://hdl.handle.net/20.500.14352/60427
LA eng
NO Project PR-84-0078-C02-02.
DS Docta Complutense
RD 20 abr 2025