Browsing by Author "Betzler, Christian"
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- Correction to: A two million year record of low-latitude aridity linked to continental weathering from the MaldivesPublication . Kunkelova, Tereza; Jung, Simon J. A.; de Leau, Erica S.; Odling, Nick; Thomas, Alex L.; Betzler, Christian; Eberli, Gregor P.; Alvarez-Zarikian, Carlos A.; Alonso-Garcia, Montserrat; Bialik, Or M.; Blättler, Clara L.; Guo, Junhua A.; Haffen, Sébastien; Horozal, Senay; Mee, Anna L. H.; Inoue, Mayuri; Jovane, Luigi; Lanci, Luca; Laya, Juan C.; Lüdmann, Thomas; Bejugam, Nagender N.; Nakakuni, Masatoshi; Niino, Kaoru; Petruny, Loren M.; Pratiwi, Santi D.; Reijmer, John J. G.; Reolid, Jesús; Slagle, Angela L.; Sloss, Craig R.; Su, Xiang; Swart, Peter K.; Wright, James D.; Yao, Zhengquan; Young, Jeremy R.; Lindhorst, Sebastian; Stainbank, Stephanie; Rueggeberg, Andres; Spezzaferri, Silvia; Carrasqueira, Igor; Yu, Siyao; Kroon, DickIn the original version of this article (Kunkelova et al. 2018), published on 18 December 2018, there was 1 error in the author name of Dr. Yu.
- Cyclic anoxia and organic rich carbonate sediments within a drowned carbonate platform linked to Antarctic ice volume changes: Late Oligocene-early Miocene MaldivesPublication . Swart, Peter K.; Blattler, Clara L.; Nakakuni, Masatoshi; Mackenzie, Greta J.; Betzler, Christian; Eberli, Gregor P.; Reolid, Jesus; Alonso-Garcia, Montserrat; Slagle, Angela L.; Wright, James D.; Kroon, Dick; Reijmer, John J. G.; Mee, Anna L. Hui; Young, Jeremy R.; Alvarez-Zarikian, Carlos A.; Bialik, Orr M.; Guo, Junhua Adam; Haffen, Sebastian; Horozal, Senay; Inoue, Mayuri; Jovane, Luigi; Lanci, Luca; Laya, Juan Carlos; Luedmann, Thomas; Nath, B. Nagender; Niino, Kaoru; Petruny, Loren M.; Pratiwi, Santi Dwi; Su, Xiang; Sloss, Craig R.; Yao, ZhengquanThis paper reports on the newly discovered occurrence of thick sequences (similar to 100 m) of Late Oligocene and Early Miocene (similar to 24.9 to similar to 20 Ma) interbedded organic-rich sediments (sapropels) and pelagic (organic poor) carbonates at Sites 01466 and U1468 drilled in the Maldives archipelago during the International Ocean Discovery Program (IODP) Expedition 359. This occurrence is unusual in that this sequence is located > 1000 m above the surrounding ocean floor within an inter-atoll basin and not linked to any known global oceanic events. Total organic content reaches as high as 35% in the darker layers, while the interbedded carbonates have concentrations of less than 0.1%. Trace elements characteristic of anoxic waters, such as Mo, V, Cr, U, and Pb, correlate positively with concentrations of organic carbon. Nitrogen isotopic data show no evidence that the intervals of high total organic carbon are related to enhanced productivity driven by upwelling. Instead, high organic carbon is associated with intervals of anoxia. We propose that sea-level fluctuations linked to changes in Antarctic ice volume restricted exchange with the open ocean causing bottom waters of the inter-atoll basin to become anoxic periodically. The architecture of the platform at the end of the Oligocene, combined with the global sea-level highstand, set the stage for orbitally-driven sea-level changes producing cyclic deposition of sapropels. The proposed mechanism may serve as an analogue for other occurrences of organic carbon rich sediments within carbonate platform settings. (C) 2019 Elsevier B.V. All rights reserved.
- Dataset of characteristic remanent magnetization and magnetic properties of early Pliocene sediments from IODP Site U1467 (Maldives platform)Publication . Lanci, Luca; Zanella, Elena; Jovane, Luigi; Galeotti, Simone; Alonso-Garcia, Montserrat; Alvarez-Zarikian, Carlos A.; Bejugam, Nagender Nath; Betzler, Christian; Bialik, Or M.; Blättler, Clara L.; Eberli, Gregor P.; Guo, Junhua Adam; Haffen, Sébastien; Horozal, Senay; Inoue, Mayuri; Kroon, Dick; Laya, Juan Carlos; Hui Mee, Anna Ling; Lüdmann, Thomas; Nakakuni, Masatoshi; Niino, Kaoru; Petruny, Loren M.; Pratiwi, Santi D.; Reijmer, John J.G.; Reolid, Jesús; Slagle, Angela L.; Sloss, Craig R.; Su, Xiang; Swart, Peter K.; Wright, James D.; Yao, Zhengquan; Young, Jeremy R.This data article describes data of magnetic stratigraphy and anisotropy of isothermal remanent magnetization (AIRM) from "Magnetic properties of early Pliocene sediments from IODP Site U1467 (Maldives platform) reveal changes in the monsoon system" [1]. Acquisition of isothermal magnetization on pilot samples and anisotropy of isothermal remanent magnetization are reported as raw data; magnetostratigraphic data are reported as characteristic magnetization (ChRM).
- Magnetic properties of early Pliocene sediments from IODP Site U1467 (Maldives platform) reveal changes in the monsoon systemPublication . Lanci, Luca; Zanella, Elena; Jovane, Luigi; Galeotti, Simone; Alonso-Garcia, Montserrat; Alvarez-Zarikian, Carlos A.; Bejugam, Nagender Nath; Betzler, Christian; Bialik, Or M.; Blattler, Clara L.; Eberlik, Gregor P.; Guo, Junhua Adam; Haffen, Sebastien; Horozal, Senay; Inoue, Mayuri; Kroon, Dick; Laya, Juan Carlos; Mee, Anna Ling Hui; Luedmann, Thomas; Nakakunir, Masatoshi; Niino, Kaoru; Petruny, Loren M.; Pratiwi, Santi D.; Reijmer, John J. G.; Reolid, Jesus; Slagle, Angela L.; Sloss, Craig R.; Su, Xiang; Swart, Peter K.; Wright, James D.; Yao, Zhengquan; Young, Jeremy R.We report a study of the magnetic stratigraphy and the anisotropy of isothermal remanent magnetization of Pliocene sediments from International Ocean Discovery Program (IODP) Site U1467 drilled in the Maldives platform (Indian Ocean) during Exp. 359. Magnetic stratigraphy gives a precise record of geomagnetic reversals of the early Pliocene from approximately 5.3 Ma to 3.1 Ma providing a detailed age model in an interval where the biostratigraphic record is scarce. We use the anisotropy of isothermal remanent magnetization (AIRM) to investigate the statistical orientation of fine magnetic particles and provide data on the strength and direction of bottom currents during the early Pliocene. The strength of bottom currents recorded by the AIRM, shows a prominent increase at the top of Chron C3n.1n (about 4.2 Ma), and the current direction (NE - SW) is consistent with that of modern instrumental measurements. Since bottom currents in the Maldives are driven by the monsoon, we speculate that the 4.2 Ma increase of bottom currents could mark the onset of the present-day setting, probably related to the coeval uplift phase of the Himalayan plateau.
- Ostracod response to monsoon and OMZ variability over the past 1.2 MyrPublication . Alvarez Zarikian, Carlos A.; Nadiri, Chimnaz; Alonso-Garcia, Montserrat; Rodrigues, Teresa; Huang, Huai-Hsuan M.; Lindhorst, Sebastian; Kunkelova, Tereza; Kroon, Dick; Betzler, Christian; Yasuhara, MoriakiWe present the first continuous middle through late Pleistocene record of fossil ostracods from the Maldives in the northern Indian Ocean, derived from sediment cores taken at Site U1467 by Expedition 359 of the International Ocean Discovery Program (IODP). Site U1467 lies at 487 m water depth in the Inner Sea of the Maldives archipelago, an ideal place for studying the effects of the South Asian Monsoon (SAM) system on primary productivity, intermediate depth ocean circulation, and the regional oxygen minimum zone (OMZ). The Inner Sea acts as a natural sediment trap that has undergone continuous sedimentation for millions of years with minor terrestrial influence. Our record spans from Marine Isotope Stage (MIS) 35 to the present, covering the mid Pleistocene transition (1.2-0.6 Ma) and the Mid-Brunhes Event (MBE, at similar to 480 ka) the time when ice age cycles transitioned from occurring every 40,000 years to 100,000 years. The ostracod data is interpreted alongside the existing datasets from the same site of sedimentological (grain-size) and XRF-elemental analyses, and new organic biomarker data also from Site U1467. These datasets support the paleoenvironmental interpretation of the ostracod assemblages. Ostracods are abundant and diverse, displaying a prominent change in faunal composition at the MBE related to the increase in the amplitude of glacial-interglacial cycles, which deeply affected the monsoon system and thereby the past oceanographic conditions of the Maldives Inner Sea. Furthermore, ostracods exhibit distinctly different assemblages across glacial-interglacial cycles, particularly after the MBE, and these changes convincingly correspond to variability of the OMZ. Glacial periods are characterized by ostracod indicators of well-oxygenated bottom water due to the intensification of the winter monsoon and the contraction of the OMZ. Abundant psychrospheric ostracods during glacials suggests that a southern sourced water mass, such as Antarctic Intermediate Water (AAIW) and/or Subantarctic Mode water, bathed the Maldives Inner Sea during glacial periods. In contrast, interglacial stages are characterized by ostracod species and biomarker data that indicate low-oxygen conditions and sluggish bottom water circulation pointing to an expansion of the regional OMZ due to the strengthening of the summer monsoon. Our results highlight the sensitivity of ostracods to oceanographic and climate variability.
- Sea-level and monsoonal control on the Maldives carbonate platform (Indian Ocean) over the last 1.3 million yearsPublication . Alonso-Garcia, Montserrat; Reolid, Jesus; Jimenez-Espejo, Francisco J.; Bialik, Or M.; Alvarez Zarikian, Carlos A.; Laya, Juan Carlos; Carrasquiera, Igor; Jovane, Luigi; Reijmer, John J. G.; Eberli, Gregor P.; Betzler, ChristianThe Maldives Archipelago (Indian Ocean), composed of two rows of atolls that enclose an inner sea, offers an excellent study site to explore the forcings of carbonate production at platforms. Glacial-interglacial sea-level changes have been claimed to be the main factor controlling the carbonate platform factories; however, climatic factors may also have an impact. In this work we used geochemical compositional records, obtained by X-ray fluorescence (XRF) core-scanning from the International Ocean Discovery Program (IODP) Site U1467 in the Maldives Inner Sea, to analyze the orbitally driven fluctuations on the carbonate production and export from the neritic environment into the Maldives Inner Sea over the last 1.3 million years.High Sr aragonite-rich carbonates (HSAC) from neritic settings were deposited in the Maldives Inner Sea during sea-level highstand intervals, increasing the Sr / Ca values. In contrast, low Sr / Ca values are observed coincident with sea-level lowstand periods, suggesting that large areas of the atolls were exposed or unable to grow, and therefore, there was a demise in the carbonate production and sediment export to the Maldives Inner Sea. However, comparison of the Sr / Ca values and the sea-level reconstructions for different interglacial periods before and after the mid-Brunhes event (MBE, similar to 430 ka ) indicates that sea level is not the only factor controlling the production of HSAC during sea-level highstands. The study of monsoon and primary productivity proxies ( Fe -normalized, Fe / K , and Br -normalized records) from the same site suggests that the intensity of the summer monsoon and the Indian Ocean dipole probably modulated the carbonate production at the atolls. Moreover, Marine Isotope Stage 11 stands out as a period with high sea level and extraordinary carbonate production in the Maldives platform. This outstanding carbonate production in the Maldives atolls (and in other low-latitude carbonate platforms) probably contributed to the mid-Brunhes dissolution event through a strong shelf-to-basin fractionation of carbonate deposition.
- The abrupt onset of the modern South Asian Monsoon windsPublication . Betzler, Christian; Eberli, Gregor P.; Kroon, Dick; Wright, James D.; Swart, Peter K.; Nath, Bejugam Nagender; Alvarez-Zarikian, Carlos A.; Alonso-Garcia, Montserrat; Bialik, Or M.; Blattler, Clara L.; Guo, Junhua Adam; Haffen, Sébastien; Horozal, Senay; Inoue, Mayuri; Jovane, Luigi; Lanci, Luca; Laya, Juan Carlos; Mee, Anna Ling Hui; Luedmann, Thomas; Nakakuni, Masatoshi; Niino, Kaoru; Petruny, Loren M.; Pratiwi, Santi D.; Reijmer, John J. G.; Reolid, Jesus; Slagle, Angela L.; Sloss, Craig R.; Su, Xiang; Yao, Zhengquan; Young, Jeremy R.The South Asian Monson (SAM) is one of the most intense climatic elements yet its initiation and variations are not well established. Dating the deposits of SAM wind-driven currents in IODP cores from the Maldives yields an age of 12.9 Ma indicating an abrupt SAM onset, over a short period of 300 kyrs. This coincided with the Indian Ocean Oxygen Minimum Zone expansion as revealed by geochemical tracers and the onset of upwelling reflected by the sediment's content of particulate organic matter. A weaker 'proto-monsoon' existed between 12.9 and 25 Ma, as mirrored by the sedimentary signature of dust influx. Abrupt SAM initiation favors a strong influence of climate in addition to the tectonic control, and we propose that the post Miocene Climate Optimum cooling, together with increased continentalization and establishment of the bipolar ocean circulation, i.e. the beginning of the modern world, shifted the monsoon over a threshold towards the modern system.
- A two million year record of low-latitude aridity linked to continental weathering from the MaldivesPublication . Kunkelova, Tereza; Jung, Simon J. A.; de Leau, Erica S.; Odling, Nick; Thomas, Alex L.; Betzler, Christian; Eberli, Gregor P.; Alvarez-Zarikian, Carlos A.; Alonso-Garcia, Montserrat; Bialik, Or M.; Blättler, Clara L.; Guo, Junhua A.; Haffen, Sébastien; Horozal, Senay; Mee, Anna L. H.; Inoue, Mayuri; Jovane, Luigi; Lanci, Luca; Laya, Juan C.; Lüdmann, Thomas; Bejugam, Nagender N.; Nakakuni, Masatoshi; Niino, Kaoru; Petruny, Loren M.; Pratiwi, Santi D.; Reijmer, John J. G.; Reolid, Jesús; Slagle, Angela L.; Sloss, Craig R.; Su, Xiang; Swart, Peter K.; Wright, James D.; Yao, Zhengquan; Young, Jeremy R.; Lindhorst, Sebastian; Stainbank, Stephanie; Rueggeberg, Andres; Spezzaferri, Silvia; Carrasqueira, Igor; Hu, Siyao; Kroon, DickIndian-Asian monsoon has oscillated between warm/wet interglacial periods and cool/dry glacial periods with periodicities closely linked to variations in Earth’s orbital parameters. However, processes that control wet versus dry, i.e. aridity cyclical periods on the orbital time-scale in the low latitudes of the Indian-Asian continent remain poorly understood because records over millions of years are scarce. The sedimentary record from International Ocean Discovery Program (IODP) Expedition 359 provides a well-preserved, high-resolution, continuous archive of lithogenic input from the Maldives reflecting on low-latitude aridity cycles. Variability within the lithogenic component of sedimentary deposits of the Maldives results from changes in monsoon-controlled sedimentary sources. Here, we present X-ray fluorescence (XRF) core-scanning results from IODP Site U1467 for the past two million years, allowing full investigation of orbital periodicities. We specifically use the Fe/K as a terrestrial climate proxy reflecting on wet versus dry conditions in the source areas of the Indian-Asian landmass, or from further afield. The Fe/K record shows orbitally forced cycles reflecting on changes in the relative importance of aeolian (stronger winter monsoon) during glacial periods versus fluvial supply (stronger summer monsoon) during interglacial periods. For our chronology, we tuned the Fe/K cycles to precessional insolation changes, linking Fe/K maxima/minima to insolation minima/maxima with zero phase lag. Wavelet and spectral analyses of the Fe/K record show increased dominance of the 100 kyr cycles after the Mid Pleistocene Transition (MPT) at 1.25 Ma in tandem with the global ice volume benthic δ18O data (LR04 record). In contrast to the LR04 record, the Fe/K profile resolves 100-kyr-like cycles around the 130 kyr frequency band in the interval from 1.25 to 2 million years. These 100-kyr-like cycles likely form by bundling of two or three obliquity cycles, indicating that low-latitude Indian-Asian climate variability reflects on increased tilt sensitivity to regional eccentricity insolation changes (pacing tilt cycles) prior to the MPT. The implication of appearance of the 100 kyr cycles in the LR04 and the Fe/K records since the MPT suggests strengthening of a climate link between the low and high latitudes during this period of climate transition.