Estherville meteorite, Emmet County, Iowa, USAi

Regional Level Types
Estherville meteorite	Meteorite Fall Location
Emmet County	County
Iowa	State
USA	Country

Mesosiderite-A3/4 (Stony-Iron)
Fall, 10 May 1879, 320 kg, shower with several 'stones'

Late in the afternoon a terribly loud explosion was heard from high above followed quickly by a number of additional thunderous blasts. Alerted by these sounds witnesses soon found a 4 m wide, 2 m deep crater with a 195 kg mass inside. Another large 65 kg mass and several smaller pieces were subsequently found in the next days and weeks. Estherville has been given considerable attention in the past 130+ years as it is the most massive of only 7 witnessed mesosiderite falls. Mesosiderites are complex stony-irons which have experienced dramatic impacts which have mixed once molten Fe-Ni metal with an assortment of silicate clasts. Several larger mesosiderite finds are known, but weathering creates substantive interpretation problems — especially when trying to determine which sulfides, sulfates and phosphates within an exposed meteoritical mass are pre-terrestrial and by products of exposure to the earth's environment. Estherville's Fe-Ni metal (56 wt%), with prominent nodules and frequent Widmanstätten patterns provide ample Fe-rich material for study. Likewise, Estherville's often clastic silicates (~40 wt%)— compositionally dominated by orthopyroxene with accessory plagioclase and other minor silicates — also provide ample 'stony' material for material. Schreibersite, troilite, chromite and other phases account for <5 wt% of the meteorite. Estherville is the 'Type Locality' for two minor phases, stanfieldite (a phosphate) and tetrataenite (Ni-rich tetragonal metal), discovered several decades ago.

As the research referenced here spans over a century, the reader should be alerted to changing nomenclature conventions used by various authors which are difficult to render with complete consistency. Thus, the 'whitlockite' reported here is referred to as 'merrillite' by other equally competent sources.

Other Regions, Features and Areas containing this locality

References