Regional geothermal aquifer architecture of the fluvial Lower Cretaceous Nieuwerkerk Formation – a palynological analysis

The primary challenge for efficient geothermal doublet design and deployment is the adequate prediction of the size, shape, lateral extent and thickness (or aquifer architecture) of aquifers. In the West Netherlands Basin, fluvial Lower Cretaceous sandstone-rich successions form the main aquifers for geothermal heat exploitation. Large variations in the thickness of these successions are recognised in currently active doublet systems that cannot be explained. This creates an uncertainty in aquifer thickness prediction, which increases the uncertainty in doublet lifetime prediction as it has an impact on net aquifer volume. The goal of this study was to improve our understanding of the thickness variations and regional aquifer architecture of the Nieuwerkerk Formation geothermal aquifers. For this purpose, new palynological data were evaluated to correlate aquifers in currently active doublet systems based on their chronostratigraphic position and regional Maximum Flooding Surfaces. Based on the palynological cuttings analysis, the fluvial interval of the Nieuwerkerk Formation was subdivided into two successions: a Late Ryazanian to Early Valanginian succession and a Valanginian succession. Within these successions trends were identified in sandstone content. In combination with seismic interpretation, maps were constructed that predict aquifer thickness and their lateral extent in the basin. The study emphasises the value of palynological analyses to reduce the uncertainty of fluvial hot sedimentary aquifer exploitation

A large Late Miocene cetotheriid (Cetacea, Mysticeti) from the Netherlands clarifies the status of Tranatocetidae

Cetotheriidae are a group of small baleen whales (Mysticeti) that evolved alongside modern rorquals. They once enjoyed a nearly global distribution, but then largely went extinct during the Plio-Pleistocene. After languishing as a wastebasket taxon for more than a century, the concept of Cetotheriidae is now well established. Nevertheless, the clade remains notable for its variability, and its scope remains in flux. In particular, the recent referral of several traditional cetotheriids to a new and seemingly unrelated family, Tranatocetidae, has created major phylogenetic uncertainty. Here, we describe a new species of Tranatocetus, the type of Tranatocetidae, from the Late Miocene of the Netherlands. Tranatocetus maregermanicum sp. nov. clarifies several of the traits previously ascribed to this genus, and reveals distinctive auditory and mandibular morphologies suggesting cetotheriid affinities. This interpretation is supported by a large phylogenetic analysis, which mingles cetotheriids and tranatocetids within a unified clade. As a result, we suggest that both groups should be reintegrated into the single family Cetotheriidae

La découverte d’un Balaenomorpha (<i>Persufflatius renefraaijeni</i> n. gen., n. sp.) du Miocène supérieur des Pays-Bas apporte un éclairage nouveau sur l’anatomie crânienne de parents anciens des rorquals

Un Balaenomorpha (Cetacea, Mysticeti) basal, Persufflatius renefraaijeni n. gen., n. sp., est décrit à partir de matériel crânien découvert dans des dépôts du Miocène supérieur à Liessel (Pays-Bas). Grâce à l’analyse palynologique d’un échantillon de sédiment associé au spécimen, celui-ci est plus précisément daté du Tortonien supérieur (Dinozone SNS M14: c. 8.2-7.6 Ma). Dans notre analyse phylogénétique, le nouveau taxon se positionne à la base du clade diversifié menant aux rorquals modernes. Malgré son état fragmentaire (seule la partie droite du basicrâne est préservée), l’holotype améliore notre connaissance de l’anatomie crânienne de ces parents anciens des rorquals actuels, qui sont relativement mal représentés dans le registre fossile. Plusieurs régions du crâne (le processus post-glénoïde du squamosal, la base du processus zygomatique du squamosal, la portion antéromédioventrale du squamosal, et l’exoccipital) montrent un renflement inhabituel (pachyostose) qui donne à l’ensemble de la partie latérale du basicrâne un aspect boursouflé. Dataset GBIFA basal member of Balaenomorpha (Cetacea, Mysticeti), Persufflatius renefraaijeni, n. gen., n. sp., is described based on cranial material discovered in upper Miocene deposits of Liessel (the Netherlands). Thanks to the palynological analysis of an associated sediment sample, the specimen is dated from the late Tortonian (Dinozone SNS M14: c. 8.2-7.6 Ma). Our phylogenetic analysis recovers the new taxon at the base of the successful crown mysticete clade leading to modern rorquals. Though the holotype is only partially preserved (it consists of the partial right side of the neurocranium), it provides new data on the cranial anatomy of these early relatives of extant rorquals, which are poorly represented in the global fossil record. Several skull parts (postglenoid process of the squamosal, base of the zygomatic process of the squamosal, the anteromedioventral portion of the squamosal bone, and the exoccipital) show unusual swelling due to pachyostosis, giving the whole lateral basicranial region an inflated aspect. GBIF dataset</p

Organic proxies and tetraether lipids fractional abundances of Hank core

The Pliocene is often regarded as a suitable analogue for future climate, due to an overall warmer climate (2-3 °C) coupled with atmospheric CO2 concentrations largely similar to present values (∼400 ppmv). Numerous Pliocene sea surface temperature (SST) records are available, however, little is known about climate in the terrestrial realm. Here we generated a Pliocene continental temperature record for Northwestern Europe based on branched glycerol dialkyl glycerol tetraether (brGDGT) membrane lipids stored in a marine sedimentary record from the western Netherlands. The total organic carbon (TOC) content of the sediments and its stable carbon isotopic composition (δ ^13^C~org~) indicate a strong transition from primarily marine derived organic matter (OM) during the Pliocene, to predominantly terrestrially derived OM after the transition into the Pleistocene. This trend is supported by the ratio of branched and isoprenoid tetraethers (BIT index). The marine-terrestrial transition indicates a likely change in brGDGT sources in the core, which may complicate the applicability of the brGDGT paleotemperature proxy in this setting. Currently, the application of the brGDGT-based paleothermometer on coastal marine sediments has been hampered by a marine overprint. Here, we propose a method to disentangle terrestrial and marine sources based on the degree of cyclization of tetramethylated brGDGTs (#rings) using a linear mixing model based on the global soil calibration set and a newly developed coastal marine temperature transfer function. Application of this method on our brGDGT record resulted in a 'corrected' terrestrial temperature record (MATterr). This latter record indicates that continental temperatures were ∼12-14 °C during the Early Pliocene, and 10.5-12 °C during the Mid Pliocene, confirming other Pliocene pollen based terrestrial temperature estimates from Northern and Central Europe. Furthermore, two colder (Δ 5-7 °C) periods in the Pliocene MATterr record show that the influence of Pliocene glacials reached well into NW Europe

Dinoflagellate cysts abundance and events of ODP Hole 189-1168A sediments

Palynomorphs were studied in samples from Ocean Drilling Program (ODP) Leg 189, Hole 1168A (slope of the western margin of Tasmania; 2463 m water depth). Besides organic-walled dinoflagellate cysts (dinocysts), broad categories of other palynomorphs were quantified in terms of relative abundance. In this contribution, we provide an overview of the early late Eocene-Quaternary dinocyst distribution and illustrate main trends in palynomorph distribution. Dinocyst species throughout Hole 1168A are largely cosmopolitan with important contributions of typical low-latitude taxa and virtual absence of endemic Antarctic taxa. Dinocyst stratigraphic distribution broadly matches that known from the Northern Hemisphere and equatorial regions, although significant differences are noted. Selected potentially biochronostratigraphically useful events are summarized. The distribution of dinocysts in the middle-upper Miocene interval is rather patchy, probably due to prolonged exposure to oxygen. An important general aspect in the dinocyst assemblages is the near absence of Antarctic endemic species and the apparent influence of relatively warm waters throughout the succession at Site 1168. General palynomorph distribution indicates continued deepening from an initial shallow, even restricted, marine setting from late Eocene-Quaternary times. A curious massive influx of small skolochorate acritarchs is recorded throughout the late early-early middle Miocene; the significance of this signal is not yet understood. A general long-term oligotrophic nature of the surface waters influencing Site 1168 is suggested from the low abundance of (proto) peridinioid, presumably heterotrophic, species. The overall dinocyst distribution pattern corresponds to the long-term existence of a Leeuwin-like current influencing the region, including Site 1168, confirming results of earlier studies on other microfossil groups. The occasional influence of colder surface water conditions is, however, also apparent, notably during the late Pliocene-Quaternary, indicating the potential of high-resolution dinocyst analysis for future paleoceanographic studies