Cretaceous–Paleogene boundary Cretaceous–Paleogene boundary The Cretaceous–Paleogene (K–Pg) boundary, formerly known as the Cretaceous–Tertiary (K-T) boundary, is a geological signature, usually a thin band of rock. "K", the first letter of the German word "Kreide" (chalk), is the traditional abbreviation for the Cretaceous Period and "Pg" is the abbreviation for the Paleogene Period. The K–Pg boundary marks the end of the Cretaceous Period, the last period of the Mesozoic Era, and marks the beginning of the Paleogene Period, the first period of the Cenozoic Era. Its age is usually estimated at around 66 Ma (million years ago), with radiometric dating yielding a more
Partridge Island (Nova Scotia) geological period between 208 and 220 million years ago, rivers swollen by intense rains carried coarse sediments (now sedimentary rocks) from nearby highlands into the Fundy Basin. Other deposits came from wind-blown sand dunes. Later, large lakes formed on the central part of the basin depositing finer sediments up to 1,000 metres thick and, as they dried up periodically, they left behind salt and gypsum deposits. The red sedimentary sandstone base of Partridge Island dates from the late Triassic period. The covering layer of dark basalt was formed from magma and lava eruptions in the Jurassic period between 175 and