Table A1 LA-ICP-MS zircon U-Pb data of Laoniushan granitoids

The NWW-striking Qinling Orogen formed in the Triassic by collision between the North China and Yangtze Cratons. Triassic granitoid intrusions, mostly middle- to high-K, calc-alkaline in composition, are widespread in this orogen, but contemporaneous intrusions are rare in the southern margin of the North China Craton, an area commonly considered as the hinterland belt of the orogen. In this paper, we report zircon U-Pb ages, elemental geochemistry, and Sr-Nd-Hf isotope data for the Laoniushan granitoid complex that was emplaced in the southern margin of the North China Craton. Zircon U-Pb dating shows that the complex was emplaced in the late Triassic (228±1 to 215±4 Ma), indicating that it is part of the post-collisional magmatism in the Qinling Orogen. The complex consists of, from early to late, biotite monzogranite, quartz diorite, quartz monzonite, and hornblende monzonite, which have a wide compositional range, e.g., SiO2=55.9-70.6 wt%, K2O+Na2O=6.6-10.2 wt%, and Mg# of 24 to 54. Rocks of the biotite monzogranite have high Al2O3(15.5-17.4 wt%), Sr(396-1398 ppm) and Ba(1284-3993 ppm) contents and La/Yb(mostly 14-30) and Sr/Y(mostly 40-97) ratios, but low Yb(mostly 1.3-1.6 ppm) and Y(mostly14-19 ppm) contents, features typical of adakite. The quartz monzonite, hornblende monzonite and quartz diorite have a shoshonitic affinity, with K2O up to 5.58 wt% and K2O/Na2O ratios averaging 1.4. The rocks are characterized by strong LREE/HREE fractionation in chondrite-normalized REE pattern, without obvious Eu anomalies, and show enrichment in large ion lithophile elements but depletion in high field strength elements (Nb, Ta, Ti). The biotite monzogranite (228 Ma) has initial 87Sr/86Sr ratios of 0.7061 to 0.7067, eNd(t) values of -9.2 to -12.6, and ?Hf(t) values of -9.0 to -15.1; whereas the shoshonitic granitoids (mainly 217-215 Ma) have similar initial 87Sr/86Sr ratios (0.7065 to 0.7075) but more radiogenic eNd(t) (-12.4 to -17.0) and eHf(t) (-14.1 to -17.0). The Sr-Nd-Hf isotope data indicate that the rocks were likely generated by partial melting of an ancient lower continental crust with heterogeneous compositions, as partly confirmed by the widespread presence of the early Paleoproterozoic inherited zircons. Mafic microgranular enclaves (MMEs), characterized by fine-grained igneous textures and an abundance of acicular apatites, are common in the Laoniushan complex. Compared with the host rocks, they have lower SiO2 (48.6-53.7 wt.%) and higher Mg# (51-56), Cr (122-393 ppm), and Ni (24-79 ppm), but equivalent Sr-Nd isotope compositions, indicating that the MMEs likely originated from an ancient enriched lithospheric mantle. The abundance of MMEs in the granitoid intrusions suggests that magma mixing plays an important role in the generation of the Laoniushan complex. Collectively, it is suggested that the Laoniushan complex was a product of post-collisional magmatism related to lithospheric extension following slab break-off. Formation of the adakitic and shoshonitic intrusions in the Laoniushan complex indicates that the Qinling Orogen had evolved into a post-collisional setting by about 230-210 Ma.

Benthic foraminifera and sea level analyses from IODP Hole 310-M0005D

The course of sea-level fluctuations during Termination II (TII; the penultimate deglaciation), which is critical for understanding ice-sheet dynamics and suborbital climate variability, has yet to be established. This is partly because most shallow-water sequences encompassing TII were eroded during sea-level lowstands of the last glacial period or were deposited below the present sea level. Here we report a new sequence recording sea-level changes during TII in the Pleistocene sequence at Hole M0005D (water depth: 59.63 m below sea level [mbsl]) off Tahiti, French Polynesia, which was drilled during Integrated Ocean Drilling Program Expedition 310. Lithofacies variations and stratigraphic changes in the taxonomic composition, preservation states, and intraspecific test morphology of large benthic foraminifers indicate a deepening-upward sequence in the interval from Core 310-M0005D-26R (core depth: 134 mbsl) through -16R (core depth: 106 mbsl). Reconstruction of relative sea levels, based on paleodepth estimations using large benthic foraminifers, indicated a rise in sea level of about 90 m during this interval, suggesting its correlation with one of the terminations. Assuming that this rise in sea level corresponds to that during TII, after correcting for subsidence since the time of deposition, a highstand sea-level position would be 2 ± 15 m above present sea level (masl), which is generally consistent with highstand sea-level positions in MIS 5e (4 ± 2 masl). If this rise in sea level corresponds to that during older terminations, the subsidence-corrected highstand sea-level positions (30 ± 15 masl for Termination III and 54 ± 15 masl for Termination IV) are not consistent with reported ranges of interglacial sea-level highstands (-18 to 15 masl). Therefore, the studied interval likely records the rise in sea level and associated environmental changes during TII. In particular, the intervening cored materials between the two episodes of sea-level rise found in the studied interval might record the sea-level reversal event during TII. This conclusion is consistent with U/Th ages of around 133 ka, which were obtained from slightly diagenetically altered (i.e., < 1% calcite) in situ corals in the studied interval (Core 310-M0005D-20R [core depth: 118 mbsl]). This study also suggests that our inverse approach to correlate a stratigraphic interval with an approximate time frame could be useful as an independent check on the accuracy of uranium-series dating, which has been applied extensively to fossil corals in late Quaternary sea-level studies.

Arrecifes de corales de aguas frías como posibles indicadores de emisiones de hidrocarburos en el Golfo de Cádiz

El presente documento trata de exponer la relación existente entre los corales de aguas frías encontrados en el Golfo de Cádiz (Atlántico NE) con los procesos tectónicos y las estructuras relacionadas con la migración y la emisión de fluidos ricos en hidrocarburos (principalmente metano). Para ello, desde el año 2000 hasta la actualidad, se han llevado a cabo diversas campañas oceanográficas en las cuales se han obtenido datos y muestras relacionadas con las emisiones de hidrocarburos al fondo marino. Gracias a los datos y las muestras recogidas durante las campañas se han creado una base de datos, en la que se reúnen todos los datos significativos relacionados con las campañas oceanográficas y con el objeto de este trabajo. Para finalizar, tras la creación de la base de datos, y con las muestras proporcionadas por el IGME recogidas durante la campaña oceanográfica MVSEIS08, se han podido llevar a cabo diversos estudios de laboratorio como la racemización de aminoácidos, análisis de biomarcadores así como la datación de los esqueletos aragoníticos de los corales de aguas frías mediante la técnica de U-Th en un futuro, con el objetivo de esclarecer la relación existente entre estas emisiones de fluidos a través de diversas estructuras y los corales de aguas frías, su edad, y en última instancia determinar los cambios producidos en la composición química de la masa de agua atlántica así como la variación de las corrientes en el Golfo de Cádiz durante el último periodo glaciar. ABSTRACT This project attempts to explain the relationship between cold-water coral found in the Gulf of Cadiz (NE Atlantic) with tectonic processes and structures related to migration and hydrocarbon-rich fluids emissions (mainly methane). Since 2000 until present, have conducted various oceanographic cruises in which data were obtained and samples related to hydrocarbon emissions to the seabed. Thanks to data and samples collected during the cruises, I have created a database in which all gather meaningful data related to oceanographic and the object of this work. Finally, after the creation of the database, and the samples provided by the IGME collected during the oceanographic cruise MVSEIS08 have been able to carry out laboratory studies of racemization of aminoacids, biomarkers analysis and dating of aragonitic skeletons of cold-water corals in a future by U-Th data , in order to clarify the relationship between these fluids emissions through various structures, ages cold-water corals, and ultimately determine changes in the chemical composition of Atlantic water mass and the change of currents in the Gulf of Cadiz during the last glacial period.

Evolución paleoambiental de la Península Ibérica desde hace 1 Ma a partir de los biomarcadores del registro de la Turbera de Padul (Granada)

La Turbera de Padul, en la Provincia de Granada, ofrece unas posibilidades de estudio muy atractivas desde el punto de vista de la reconstrucción paleoambiental. Se trata de una fosa tectónica subsidente de naturaleza detrítica, a cuyo techo aparecen alternantes niveles de turba. El sondeo, de 107 metros, se realizó en un punto donde los estratos de turba aparecen a mayor profundidad, lo que permite obtener un registro geoquímico orgánico con mucho detalle con una antigüedad de hasta 1Ma. Se tomaron muestras cada 20 cm para el análisis de biomarcadores. Estos biomarcadores se obtuvieron mediante extracción Soxhlet, posterior separación de fracciones de diferente polaridad mediante Cromatografía en Columna, con Gel de Sílice y Alúmina, y posteriormente el análisis e identificación por Cromatografía de Gases - Espectrometría de masas, con confirmación de los compuestos químicos identificados por comparación con Bibliotecas de Espectros de Masas. La datación del sondeo se realizó utilizando distintos métodos como datación por 14C, U/Th, y datación por racemización de aminoácidos. Los resultados dataron el muro del sondeo con una antigüedad de 1 millón de años. El estudio de los biomarcadores ha permitido identificar episodios con distintas características en un escenario complejo, como es la Turbera de Padul, donde el aporte de agua por fusión nival complica la interpretación paleoambiental, y es la responsable de la existencia de la lámina de agua en la turbera en periodos secos con temperaturas elevadas. Se han identificado series de n-alcanos, de n-metilcetonas y series de nalcanoles, que han permitido identificar la aportación de materia orgánica de distintas fuentes al sedimento y por tanto la interpretación paleoambiental. La identificación de diterpenoides fenólicos (cis-Totatol, trans-Totarol y Ferruginol) han permitido identificar episodios de clima templado y húmedo con proliferación de cupresáceas, y precipitaciones abundantes. Por otro lado, se han identificado triterpenoides como el Friedelan-3-ona (Friedelin) y el A-norfriedel-8en-10-ona, cuya relación como precursor (Friedelin) y producto (A-norfriedel-8en-10-ona) ha permitido identificar episodios con fluctuaciones del espesor de la lámina de agua y aporte de material vegetal. ABSTRACT The Bog of Padul, in the province of Granada, offers very attractive possibilities for the study of paleoenvironmental reconstruction. It is a subsiding graben of detrital nature, whose upper part appear alternating peat levels. The core of 107 meters, obtained from a borehole drilled in a place where the layers of peat appear deeper, allowing to obtain organic geochemist information along the last 1 million years. Every 20 cm samples for biomarkers analysis were taken. These biomarkers were obtained by Soxhlet extraction, subsequent separation of fractions of different polarity by column chromatography with silica gel and alumina, and then analyzed and identified by gas chromatography - mass spectrometry, with confirmation of the chemicals identified by comparison to mass spectral libraries. The dating of the core was conducted using different methods such as 14C dating, U/Th, and amino acid racemization dating. The results dated the base of the core to be 1 million years old. The study has identified biomarkers episodes with different characteristics in a complex scenario, such as the Bog of Padul, where the contribution of snowmelt water complicates the paleoenvironmental interpretation, and is responsible for the existence of a sheet of water in dry periods with high temperatures. There have been identified series of n-alkanes, n-methyl ketones and series of n-alkanols that have shown the contribution of different organic matter sources to the sediment and therefore allowed to paleo interpretation. The identification of phenolic diterpenoids (cis-Totatol, trans-Totarol and Ferruginol) have identified episodes of mild and humid climate with proliferation of Cupressaceae, and abundant rainfall. In addition, triterpenoids have been identified, as the friedelan-3-one (friedelin) and the A-norfriedel-8en-10-one, whose relationship as precursor (friedelin) and product (A-norfriedel-8en-10-one) has identified episodes with fluctuations on the thickness of the sheet of water and supply of plant material debris.

Oceanic minerals: Their origin, nature of their environment, and significance

The chemical and isotopic compositions of oceanic biogenic and authigenic minerals contain invaluable information on the evolution of seawater, hence on the history of interaction between tectonics, climate, ocean circulation, and the evolution of life. Important advances and greater understanding of (a) key minor and trace element cycles with various residence times, (b) isotopic sources and sinks and fractionation behaviors, and (c) potential diagenetic problems, as well as developments in high-precision instrumentation, recently have been achieved. These advances provided new compelling evidence that neither gradualism nor uniformitarianism can explain many of the new important discoveries obtained from the chemistry and isotopic compositions of oceanic minerals. Presently, the best-developed geochemical proxies in biogenic carbonates are 18O/16O and Sr/Ca ratios (possibly Mg/Ca) for temperature; 87Sr/86Sr for input sources, Cd/Ca and Ba/Ca ratios for phosphate and alkalinity concentrations, respectively, thus also for ocean circulation; 13C/12C for ocean productivity; B isotopes for seawater pH;, U, Th isotopes, and 14C for dating; and Sr and Mn concentrations for diagenesis. The oceanic authigenic minerals most widely used for chemical paleoceanography are barite, evaporite sulfates, and hydrogenous ferromanganese nodules. Marine barite is an effective alternative monitor of seawater 87Sr/86Sr, especially where carbonates are diagenetically altered or absent. It also provides a high-resolution record of seawater sulfate S isotopes, (evaporite sulfates only carry an episodic record), with new insights on factors affecting the S and C cycles and atmospheric oxygen. High-resolution studies of Sr, Nd, and Pb isotopes of well-dated ferromanganese nodules contain invaluable records on climate driven changes in oceanic circulation.

Age and isotopes in bottom sediments from Core VER-99-1-St2, Baikal Lake

A simple, reliable, and efficient method has been elaborated for direct determination of isotopic composition of authigenic uranium in siliceous lacustrine sediments. The method is based on studying kinetics of selective extraction of authigenic uranium from sediments by weak solutions of ammonium hydrocarbonate followed by ICP-MS analysis of nuclides. To estimate contamination of authigenic uranium by terrigenous one contents of 232Th and some other clastogenic elements in the extracts were measured simultaneously. Selectivity of extraction of authigenic uranium from the sediments treated with 1% NH4HCO3 solution appeared to be no worse than 99%. The method was applied to analysis of isotopic composition of authigenic uranium at several key horizons of the earlier dated core from the Baikal Lake. Measurements directly show that 234U/238U values in Baikal water varied depending on climate, which contradicts existing hypotheses. Measured 234U/238U ratios in water of the paleo-Baikal match corresponding values reconstructed from isotopic data for total uranium in the sediments on supposition that U/Th ratio is constant in terrigenous fraction of the sediments. Direct experimental determination of total and authigenic nuclides in sediments enhances potentiality of the method for 234U-230Th dating of non-carbonate lacustrine sediments including those from the Baikal Lake within intervals corresponding to periods of glaciation, when sediments were rich in terrigenous components. Portions of terrigenous and authigenic uranium are well separated and we can study variability of sources of terrigenous matter and refine the earlier model for reconstructing climate humidity in the East Siberia.

Palaeoclimatic implications of the growth history and stable isotope (delta O-18 and delta C-13) geochemistry of a Middle to Late Pleistocene stalagmite from central-western Italy

The age structure and, stable isotope composition of a stalagmite (CC I) from an upland cave in central-western Italy were studied to investigate regional response to global climatic changes. Four growth phases are constrained by 28 thermal ionization and multi-collector inductively coupled plasma mass spectrometry Th-U ages and reveal intermittent deposition through the period between Marine isotope Stage (MIS) 11 and 3 (similar to380 and similar to43 kyr). Most of the growth took place between similar to380 and similar to280 kyr, a period punctuated briefly by a hiatus in deposition through the glacial maximum of MIS 10. Growth was terminated abruptly at 280 kyr just prior to the MIS 8 glacial maximum. With a present-day chamber temperature of 7.5 degreesC, the timing of hiatuses close to these glacial maxima point to freezing conditions at the time. No deposition was recorded through the entirety of MIS 7 and most of MIS 6, whilst two minor growth phases occurred at similar to141-125 and similar to43 kyr. Growth at 141 kyr indicates temperatures >0 degreesC at a time when MIS 6 ice volumes were close to their maximum. High stable carbon isotope (delta(13)C) values (similar to2.8parts per thousand to +3.1parts per thousand) throughout the stalagmite's growth reflect a persistently low input of biogenic CO2, indicating that the steep, barren and alpine-like recharge area of today ha's been in existence for at least the last similar to380 kyr. During MIS 9, the lowest delta(13)C values occur well after maximum interglacial conditions, suggesting a lag in the development of post-glacial soils in this high-altitude karst. The stable oxygen isotope (delta(18)O) trends match the main structural features of the major climate proxy records (SPECMAP, Vostok and Devils Hole), suggesting that the delta(18)O of CC1 has responded to global-scale climate changes, whilst remarkable similarity exists between CC1 delta(18)O and regional sea-surface temperature reconstructions from North Atlantic core ODP980 and southwest Pacific marine core MD97-2120 through the most detailed part of the CC1 record, MIS 9-8. The results suggest that CC1 and other stalagmites from the cave have the potential to capture a long record of regional temperature trends, particularly in regards to the relative severity of Pleistocene glacial stages. (C) 2004 Elsevier B.V. All rights reserved.

Assigning dates to thin gneissic veins in high-grade metamorphic terranes: A cautionary tale from Akilia, southwest Greenland

A granodiorite from Akilia, southwest Greenland, previously suggested to date putative life-bearing rocks to greater than or equal to3.84 Ga, is re-investigated using whole-rock major and trace-element geochemistry, and detailed cathodoluminescence image-guided secondary ion mass spectrometer analyses of zircon U-Th-Pb and rare earth elements. Complex zircon internal structure reveals three episodes of zircon growth and/or recrystallization dated to c. 3.84 Ga, 3.62 Ga and 2.71 Ga. Rare earth element abundances imply a significant role for garnet in zircon generation at 3.62 Ga and 2.71 Ga. The 3.62 Ga event is interpreted as partial melting of a c. 3.84 Ga grey gneiss precursor at granulite facies with residual garnet. Migration of this 3.62 Ga magma (or melt-crystal mush) away from the melt source places a maximum age limit on any intrusive relationship. These early Archaean relationships have been complicated further by isotopic reworking in the 2.71 Ga event, which could have included a further episode of partial melting. This study highlights a general problem associated with dating thin gneissic veins in polyphase metamorphic terranes, where field relationships may be ambiguous and zircon inheritance can be expected.