(1) The George Washington University, 20052 Washington, DC, USA;(2) U.S. Naval Research Laboratory, 20375 Washington, DC, USA;(3) Geocenters Inc, 20749 Ft. Washington, MD, USA
Abstract:
High-resolution powder X-ray diffraction measurements were carried out on gas hydrates in the angle-dispersive mode using a synchrotron radiation source. In contrast to the structural studies of laboratory-grown gas hydrates, this study has been performed on naturally grown clathrate hydrates obtained from the sea floor at different geographic locations. While the hydrate samples of the Cascadia Margin exhibit a preponderance of structure I, those from the Gulf of Mexico consist of mixed structures, namely structure II, structure I and structure H. Ice in structure Ih is inherently present in all the clathrate hydrate samples. PACS 61.10.Nz; 61.50.Ah; 61.66.Fn; 91.50.-r