XRF-Derived Cyclicity in Pliocene and Pleistocene Sediments from ODP Site 693, Dronning Maud Land, Antarctica

Orbital Forcing of West and East Antarctic Ice Sheets 3.8-3.0 Ma: A Climate Analogue in Weddell Sea ODP Site 697

“…A similar study of Dronning Maud Land ODP Site 693 by Hall, 2015 and True-Alcalá, 2015 find a dominant eccentricity forcing and secondary precession forcing in cores deposited between 4.2 and 3.6 Ma. The absence of paleomagnetics prevents further time constraint of their data.…”

“…Using an orthogonal transformation, it converts positively correlated variables into linearly uncorrelated variables called principal components (Jolliffe, 2002). The first principal component explains the largest amount of variance in the dataset, the second, orthogonal to the first, explains the second largest amount of variance, and so on (Cope, 2009;Hall, 2015). This procedure is commonly used in geophysics to identify traveling and standing waves in datasets (Horel, 1984).…”

“…The elemental count ratios used were Ag/Ti, Ba/Ti, Ca/Ti Cd/Ti, Cl/Ti, Cr/Ti, Cu/Ti, Fe/Ti, K/Ti, Mn/Ti, Mo/Ti, Ni/Ti, P/Ti, Rb/Ti, S/Ti, Sn/Ti, Sr/Ti, Zr/Ti, and Zn/Ti. Datasets were detrended to make cyclical patterns more easily identifiable (Hall, 2015). This was done by creating a second-degree polynomial trendline in each dataset, inserting the meter below sea floor depth at each interval into the equation for the trend line and then subtracting the trend line.…”

“…The dominate Milankovitch forcing and driver of the elemental processes in that wavelet is that which has the most power in the global wavelet. The peaks found in wavelet analysis correspond to lengths of sedimentation as peaks show periods and periods are lengths in the core (Hall, 2015).…”

Diffuse Spectral Reflectance-derived Pliocene and Pleistocene Periodicity from Weddell Sea, Antarctica Sediment Cores

“…Figure 3.8 shows the rates calculated from the various components plotted against each other for comparison. The Milankovitch cycle assignments, peak lengths, and sedimentation rates are shown in Table 3.2(a) (2R) and 3.2(b) (8R) along with the rates generated from 3 other datasets analyzed by Hall (2015).…”