Element abundances, loss on ignition, total analyzed abundances, CIA values, and Al-oxide/Ti-oxide ratios of sediment core CRP-2A (Table1)

• Main Authors: Krissek, Lawrence A, Kyle, Philip R
• Format: Dataset
• Language: English
• Published: PANGAEA 2000
• Subjects: 14.2 km at 096° true from Cape Roberts; Aluminium/Titanium ratio; Aluminium oxide; Antimony; Arsenic; Barium; Caesium; Calcium oxide; Calculated; Calculated from weight loss after ignition at 450 °C; Cape Roberts Project; Cerium; Chemical index of alteration; Chloride; Chromium; Copper; Core wireline system; CRP; CRP-2; CRP-2A; CWS; DEPTH; sediment/rock; Europium; Gallium; Hafnium; Instrumental neutron activation analysis (INAA) (Reimann et al.; 1998); Iron oxide; Fe2O3; Lanthanum; Lead; Loss on ignition; Lutetium; Magnesium oxide; Manganese oxide; Nickel; Niobium; off Cape Roberts; Ross Sea; Antarctica; Phosphorus oxide; Potassium oxide; Rubidium; Samarium; Sampling/drilling from ice; Scandium; see comment; Silicon dioxide; Sodium oxide; Cape Roberts; McMurdo Sound; Antarc*
• Online Access: https://doi.pangaea.de/10.1594/PANGAEA.144432; https://doi.org/10.1594/PANGAEA.144432

The CRP-2/2A core, drilled in western McMurdo Sound in October and November 1998, penetrated 624 m of Quaternary. Pliocene, lower Miocene, and Oligocene glacigenic sediments. The palaeoclimatic record of CRP-2/2A is examined using major element analyses of bulk core samples of fine grained sediments (mudstones and siltstones) and the Chemical Index of Alteration (CIA) of Nesbitt & Young (1982). The CIA is calculated from the relative abundances of AI, K, Ca, and Na oxides, and its magnitude increases as the effects of chemical weathering increase. However, changes in sediment provenance can also affect the CIA, and provenance changes are recorded by shifts in the Al2O3/TiO2 ratios and the Nb contents of these CRP-2/2A mudstones. Relatively low CIA values (40-50) occur throughout the CRP-2/2A sequence, whereas the Al2O3/TiO2 ratio decreases upsection. The major provenance change is an abrupt onset of McMurdo Volcanic Group detritus at ~300 mbsf and is best characterized by a rapid increase in Nb content in the sediments. This provenance shift is not evident in the CIA record, suggesting that a contribution from the Ferrar Dolerite to the older sediments was replaced by an input of McMurdo Volcanic Group material in the younger sediments. If this is true, then the relatively uniform CIA values indicate relatively consistent palaeoweathering intensities throughout the Oligocene and early Miocene in the areas that supplied sediment to CRP-2/2A.