Talmage maintained that Jesus Christ was born on April 6 in the year 1 BC.
Talmage was apparently the first LDS writer to propose this particular date. Mc Conkie, published major studies on the life and ministry of Jesus Christ and proposed that Jesus was born in late 5 BC or early 4 BC. Chadwick, Jerusalem Center Professor of Archaeology and Near Eastern Studies, draws upon many sources--scriptural, historical, archeological, and astronomical--to shed light on the probable date of the Savior's birth.
The age of a sample is determined by analysing several minerals within the sample. If these form a straight line then the samples are consistent, and the age probably reliable.
The slope of the line dictates the age of the sample.
Hence, the Rb/Sr ratio in residual magma may increase over time, resulting in rocks with increasing Rb/Sr ratios with increasing differentiation. Typically, Rb/Sr increases in the order plagioclase, hornblende, K-feldspar, biotite, muscovite.