Mega-monsoon variability during the late Triassic: Re-assessing the role of orbital forcing in the deposition of playa sediments in the Germanic Basin

The formation of the supercontinent Pangaea during the Permo–Triassic gave rise to an extreme monsoonal climate (often termed ‘mega-monsoon’) that has been documented by numerous palaeo-records. However, considerable debate exists about the role of orbital forcing in causing humid intervals in an otherwise arid climate. To shed new light on the forcing of monsoonal variability in subtropical Pangaea, this study focuses on sediment facies and colour variability of playa and alluvial fan deposits in an outcrop from the late Carnian (ca 225 Ma) in the southern Germanic Basin, south-western Germany. The sediments were deposited against a background of increasingly arid conditions following the humid Carnian Pluvial Event (ca 234 to 232 Ma). The ca 2·4 Myr long sedimentary succession studied shows a tripartite long-term evolution, starting with a distal mud-flat facies deposited under arid conditions. This phase was followed by a highly variable playa-lake environment that documents more humid conditions and finally a regression of the playa-lake due to a return of arid conditions. The red–green (a*) and lightness (L*) records show that this long-term variability was overprinted by alternating wet/dry cycles driven by orbital precession and ca 405 kyr eccentricity, without significant influence of obliquity. The absence of obliquity in this record indicates that high-latitude forcing played only a minor role in the southern Germanic Basin during the late Carnian. This is different from the subsequent Norian when high-latitude signals became more pronounced, potentially related to the northward drift of the Germanic Basin. The recurring pattern of pluvial events during the late Triassic demonstrates that orbital forcing, in particular eccentricity, stimulated the occurrence and intensity of wet phases. It also highlights the possibility that the Carnian Pluvial Event, although most likely triggered by enhanced volcanic activity, may also have been modified by an orbital stimulus

Underway surface water data during the Tara Oceans expedition in 2009-2012

The Tara Oceans Expedition (2009-2013) sampled the world oceans on board a 36 m long schooner, collecting environmental data and organisms from viruses to planktonic metazoans for later analyses using modern sequencing and state-of-the-art imaging technologies. Tara Oceans Data are particularly suited to study the genetic, morphological and functional diversity of plankton. During the entire expedition (2009-2013), underway measurements were obtained from a meteorological station (BATOS), a thermosalinograph (TSG, SBE 45), a Fast Repetition Rate Flurometer (FRRF, LIFT-FRR01), and a spectrophotometer (WETLabs AC-S). In 2013 underway measurements were enhanced by adding a Photosynthetically Available Radiation (PAR) sensor (QCP2350, Biospherical Instruments, Inc.), a laser spectrofluorometer (WETLabs ALFA, Chekalyuk et al., 2012) that replaced the FRRF, a spectral backscattering sensor (WETLabs Eco-bb3), a pCO2 sensor (ProOceanus CO2-Pro), a pH sensor (Satlantic, SeaFET) and a particle imaging system triggered by chlorophyll-a fluorescence (a prototype of McLane Research Laboratories' Imaging FlowCytobot, Sosik Lab, WHOI). Discrete measurements of CDOM absorption measurements were made using an Ultrapath (WPI Inc.) to calibrate the in-line AC-S. Hence the AC-S was also used to provide CDOM absorption in addition to particulate matter properties. The present dataset contains surface water data measured during the 2009-2012 campaigns of the Tara Oceans Expedition. Latitude and Longitude were obtained from TSG data. The time stamp of this data set is harmonised with that of other underway data in this collection

Harmonised data from underway navigation, meteorology and surface water measurements during the Tara Oceans expedition in 2009-2013

The Tara Oceans Expedition (2009-2013) sampled the world oceans on board a 36 m long schooner, collecting environmental data and organisms from viruses to planktonic metazoans for later analyses using modern sequencing and state-of-the-art imaging technologies. Tara Oceans Data are particularly suited to study the genetic, morphological and functional diversity of plankton. During the entire expedition (2009-2013), underway measurements were obtained from a meteorological station (BATOS), a thermosalinograph (TSG, SBE 45), a Fast Repetition Rate Flurometer (FRRF, LIFT-FRR01), and a spectrophotometer (WETLabs AC-S). In 2013 underway measurements were enhanced by adding a Photosynthetically Available Radiation (PAR) sensor (QCP2350, Biospherical Instruments, Inc.), a laser spectrofluorometer (WETLabs ALFA, Chekalyuk et al., 2012) that replaced the FRRF, a spectral backscattering sensor (WETLabs Eco-bb3), a pCO2 sensor (ProOceanus CO2-Pro), a pH sensor (Satlantic, SeaFET) and a particle imaging system triggered by chlorophyll-a fluorescence (a prototype of McLane Research Laboratories' Imaging FlowCytobot, Sosik Lab, WHOI). Discrete measurements of CDOM absorption measurements were made using an Ultrapath (WPI Inc.) to calibrate the in-line AC-S. Hence the AC-S was also used to provide CDOM absorption in addition to particulate matter properties. The present collection includes three data sets that are harmonised with a common time stamp. The source data sets given in the reference section