Environmental Change in the Southwestern Coastal Plain of Taiwan since Late Pleistocene: Using Multiple Proxies of Sedimentary Organic Matter

Abstract

ABSTRACT1 Department of Geosciences, National Taiwan University, Taipei, Taiwan, ROC * Corresponding author address: Prof. Yue-Gau Chen, Department of Geosciences, National Taiwan University, Taipei, Taiwan, ROC; E-mail: ygchen@ntu.edu.tw ) and high C/N ratios (average 9.3) with good correlation indicate that this area underwent a period of relative aridity from early Marine Isotopic Stage (MIS) 2 to the early MIS 1. In MIS 1, the δ 13 C and C/N ratio both vary initially before later steadying, indicating that the environment became progressively more stable, with C3 plants becoming dominant again. The Zai-kang core appears to have come from a shallow lagoon system that potentially preserved the record of δ 15 N from autochthonous primary producers. Regional organic source variation is revealed through the high δ 15 N values and constant C/N ratios in MIS 1 of the Zai-kang core. This may suggest that mangroves and macrophytes were the main aquatic organic matter source in the Zai-kang area during MIS 1.

Normalizing XRF-scanner data: A cautionary note on the interpretation of high-resolution records from organic-rich lakes

“…The calculated ratios then were plotted both raw and smoothed with a 5-point moving average. Analyses of TOC and TN of organic-containing samples followed standard procedures (Chen et al, 2009;Ku et al, 2005). In brief, an aliquot of decalcified sample was wrapped in a tin capsule and then combusted using a ThermoQuest EA1110 elemental analyzer at the Department of Geosciences, National Taiwan University (NTU) to measure the TOC and TN contents, and thus the atom/atom TOC/TN ratio.…”

Causes and implications of Mid- to Late Holocene relative sea-level change in the Gulf of Kachchh, western India

“…Therefore, the autochthonous component contributed by aquatic organisms, algae, and phytoplankton has a C/N ratio ranging from 4 to 10. The allochthonous constituent (mostly coming from terrestrial plants) is more refractory due to their high lignin and cellulose content and has a C/N ratio > 12 (Ku et al, 2005; Nazneen and Raju, 2017).…”