A definition for ultrapotassic rocks is introduced using the chemical screens K 2 O> 3 wt.%,
MgO> 3 wt.% and K 2 O/Na 2 O> 2 for whole-rock analyses. On this basis a data base of …

* Maps and text (Introduction and Chapter 10) from AAPG Memoir 43, Evolution of the Arctic-
North Atlantic and the Western Tethys, by Peter A. Ziegler. Adapted here for online …

his book is intended for graduate students of the Earth Sciences who require a T
comprehensive examination of the origins of igneous rocks as recorded by the isotope …

We explore the origins of anorogenic post-breakup magmatism in two areas of the mid-
Atlantic Appalachians: the New England-Quebec Province (ca. 130–120 Ma) and the …

This study reports in-situ determination of major and trace element compositions of calcite
and apatite, and U–Pb ages of apatite for carbonatites and associated okaites and ijolites …

Eight paleomagnetic poles are considered to be reliable Jurassic reference poles for
cratonic North America. These poles form a consistent chronological progression defining …

Rare earth element (REE) ore-bearing carbonatite dikes and a stock at Mountain Pass,
California, are spatially associated with a suite of ultrapotassic plutonic rocks, and it has …

Abstract Initial 87 Sr 86 Sr and 143 Nd 144 Nd ratios of some carbonatites and related
alkalic rocks intruded into the Canadian Shield between 2700 Ma and 110 Ma ago define …

Since the discovery of plate tectonics, the relative importance of driving forces of plate
motion has been debated,. Resolution of this issue has been hindered by uncertainties in …

Although the Early Jurassic initial phases of Atlantic rifting were marked by the tholeiitic
basalt flows and dikes of the Central Atlantic Magmatic Province (CAMP), the Cretaceous …