Changes in Timor Strait hydrology and thermocline structure during the past 130 ka

Cappelli, Elena Lo Giudice; Holbourn, Ann; Kuhnt, Wolfgang; Regenberg, Marcus

doi:10.1016/j.palaeo.2016.09.010

Cited by 18 publications

(8 citation statements)

References 80 publications

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“…Zr is enriched in heavy minerals (zircon) and associated with a coarser grained fraction, whereas Rb is enriched in light clay minerals and characteristic of fine grain sizes (Dypvik & Harris, 2001;Kylander et al, 2011;Schneider et al, 1997). Thus, the normalized Zr/Rb as an estimate of coarse and fine-grained detritus in the sediment can serve as a proxy of current energy (Liu et al, 2002;Lo Giudice Cappelli et al, 2016;Schulte & Speijer, 2009). We used the log ratio of potassium (K) and titanium (Ti) as a proxy of riverine sediment discharge (Kujau et al, Paleoceanography 10.1002/2016PA003030 2010), based on the assumption that K dominates in the fine-grained fluvial sediment discharge from the Mahakam River, since K weight percentages in surface samples from the Mahakam River reach relatively high values of 2.4-2.6% in the clay fraction (<2 μm) (Liu et al, 2012).…”

Section: X-ray Fluorescence Core Scanningmentioning

confidence: 99%

Variability of Indonesian Throughflow and Borneo Runoff During the Last 14 kyr

2017

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We present a high‐resolution (~20 to 100 years temporal resolution) reconstruction of hydrological changes in the Makassar Strait over the last 14 kyr from Core SO217‐18517 retrieved off the Mahakam Delta (1°32.198′S, 117°33.756′E; 698 m water depth) during the SO217 Makassar‐Java Cruise. Sea surface temperatures, based on Mg/Ca of Globigerinoides ruber and alkenone UK′37, and seawater δ18O reconstructions, based on G. ruber δ18O and Mg/Ca, in combination with sortable silt grain size measurements and X‐ray fluorescence (XRF) core scanner derived elemental data provide evidence for increased precipitation during the Bølling‐Allerød (BA) and early Holocene and for warmer and more saline surface waters and a decrease in the intensity of the Indonesian Throughflow (ITF) during the Younger Dryas (YD). XRF derived Log (Zr/Rb) records, sortable silt data and increased sedimentation rates indicate decreased winnowing, interpreted as a slowdown of the ITF thermocline flow during the YD. We attribute this decline in ITF intensity to slowdown of the Atlantic meridional overturning circulation during the YD. We suggest that changes in Makassar Strait surface hydrology during this interval of Northern Hemisphere cooling and Southern Hemisphere warming were related to a southward displacement of the Intertropical Convergence Zone.

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Section: X-ray Fluorescence Core Scanningmentioning

confidence: 99%

Variability of Indonesian Throughflow and Borneo Runoff During the Last 14 kyr

2017

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“…On the obliquity band, Core U1483 δ 18 O sw-c may not be simply driven by the lateral advection of ITF water masses, due to the absence of obliquity band variance in the δ 18 O sw-c from Cores MD06-3067 (Bolliet et al, 2011), MD01-2386 (Jian et al, 2020), and SO18540 (Zhang et al, 2021) situated within the inflow areas and the main path of the ITF (Figure 1 and Figures S2b-S2d in Supporting Information S1). However, the δ 18 O sw-c of these water masses may be additionally modified by intense vertical mixing in the Banda Sea, unlike the δ 18 O sw-c from Core SO18471 (Lo Giudice Cappelli et al, 2016), located within the ITF outflow upstream of Core U1483 (Figure 1). The lack of obliquity band variance in the δ 18 O sw-c of Core SO18471 further implies that the strong obliquity signal in Core U1483 δ 18 O sw-c may not be simply attributed to ITF advection (Figure S2e in Supporting Information S1).…”

Section: Figurementioning

confidence: 99%

“…Golden star marks Core U1483 (this study). Colored filled circles mark Jingyuan Loess Section (Sun et al., 2019), Xifeng Loess Section (Li et al., 2017), Core MD06‐3067 (Bolliet et al., 2011), Core SO18540 (Zhang et al., 2021), Core MD01‐2378 (Xu et al., 2006, 2008; Zuraida et al., 2009), Core SO18471 (Lo Giudice Cappelli et al., 2016), Core MD01‐2386 (Jian et al., 2020), and Core SO18548 (Pei, Kuhnt, Holbourn, Jöhnck, et al., 2021), respectively. Approximate extension of the Fitzroy and Ord Rivers on the northwestern Australian shelf are indicated by blue dashed lines.…”

Section: Introductionmentioning

confidence: 99%

Obliquity Induced Latitudinal Migration of the Intertropical Convergence Zone During the Past ∼410 kyr

Zhang

Holbourn

et al. 2022

Geophysical Research Letters

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Obliquity influences the latitudinal position of the Intertropical Convergence Zone (ITCZ). However, the specific forcing mechanism remains unclear due to scarcity of long‐term and high‐resolution precipitation records from the Indo‐Pacific region. Here, we present a new, extended, high‐resolution (∼2 kyr) precipitation record covering the past ∼410 kyr from a marine sedimentary sequence collected at the southern margin of the ITCZ's latitudinal displacement within the Indo‐Pacific region. By integrating this new precipitation record with the published precipitation records at the northern margin of the ITCZ's latitudinal displacement, we found that precipitation in the Northern and Southern Hemispheres varied in anti‐phase on the obliquity band, indicating that the latitudinal migration of the ITCZ was dominated by obliquity. The obliquity forcing on the latitudinal migrations of the ITCZ could be imparted by variations in the North Atlantic sea ice cover, resulting from Agulhas leakage induced changes in the ventilation strength of the Atlantic meridional overturning circulation.

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“…The increase of paleoproductivity in the ITF outflow region during this period Copyright held(s) by author(s), publishing rights belongs to publisher, pp. 167-178, DOI: 10.17794/rgn.2023.1.14 could be related to the increase in terrestrial input due to the exposure of the Sahul Shelf (Holbourn et al, 2005;Lo Giudice Cappelli et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

Ea Surface Paleoproductivity Reconstruction Based on Foraminiferal Accumulation Rate in the Western Savu Strait Since the Last Glacial Maximum (~23 Ka Bp)

Ardi

Aswan

Maryunani

et al. 2023

MGPB

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Despite its importance, sea surface paleoproductivity of the western Savu Strait is not well studied. Results from previous studies at the nearby Southwest Sumba and Sumba Strait might not be applicable due to the oceanographic difference. Foraminiferal proxies from gravity core ST10 were applied to generate sea surface paleoproductivity and thermocline depth reconstruction. Foraminiferal Accumulation Rate and Benthic Foraminiferal Accumulation Rate were used as paleoproductivity proxies while the thermocline dwellers’ relative abundance was applied as the thermocline depth proxy. This study suggested paleoproductivity increase during the Last Glacial Maximum (LGM)–~16 ka BP and Holocene (after ~11.65 ka BP) in the western Savu Strait. Thermocline depth was relatively shallower during the LGM–Last Deglaciation and became deeper afterwards. Paleoproductivity increase at LGM–~16 ka BP was caused by the Australian-Indonesian winter monsoon (AIWM)-like condition, characterized by intense coastal upwelling while the Holocene paleoproductivity increase was related to the abrupt rainfall increase which enhanced terrestrial/riverine input. Thermocline depth variability in the western Savu Strait is in-phase with thermocline depth variability in the Java upwelling region, characterized by a shallower thermocline during the LGM–Last Deglaciation (before ~11.65 ka BP) and a deeper thermocline during the Holocene (after ~11.65 ka BP). This thermocline depth shifting indicates a strong Australian-Indonesian Monsoon (AIM) influence on the paleoceanography of the western Savu Strait since LGM.

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Changes in Timor Strait hydrology and thermocline structure during the past 130 ka

Cited by 18 publications

References 80 publications

Variability of Indonesian Throughflow and Borneo Runoff During the Last 14 kyr

Variability of Indonesian Throughflow and Borneo Runoff During the Last 14 kyr

Obliquity Induced Latitudinal Migration of the Intertropical Convergence Zone During the Past ∼410 kyr

Ea Surface Paleoproductivity Reconstruction Based on Foraminiferal Accumulation Rate in the Western Savu Strait Since the Last Glacial Maximum (~23 Ka Bp)

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