[DOC] [TLE] How Volcanoes Work - Earth's Internal Heat, Energy, and Interior ... [PAR] This internal heat energy was much greater in the early stages of the Earth than it 
is ... of the Earth's interior, and (3) the radioactive decay of unstable isotopes. ... 
Most scientists believe that our solar system evolved from the accretion of ... or 
vaporized, rising beyond the earth's rocky surface to form the early oceans and 
the... [DOC] [TLE] Radioactive decay accounts for half of Earth's heat - physicsworld.com [PAR] Jul 19, 2011 ... It's hot down there, thanks in part to radioactive decay ... by the radioactive decay 
of elements such as uranium and thorium, and ... The most popular model of 
radioactive heating is based on the bulk .... If we view neutrinos as a neutral type 
of radiation we can explain nearly all radioactive decay as well as... [DOC] [TLE] Why do uranium and thorium occur naturally in Earth's crust and ... [PAR] THIS WAS INTENDED TO BE A REPLY TO ANDY MCFARLAND'S COMMENT 
ON GEORGE ... Unstable elements such aspolonium, radium, and radonwhich 
form through the ... In fact most of the heat generated in the core and mantle 
come from the ... Radioactive atoms like Uranium and Thorium; AND OTHER 
STUFF. [DOC] [TLE] Geothermal gradient - Wikipedia [PAR] Geothermal gradient is the rate of increasing temperature with respect to 
increasing depth in ... Much of the heat is created by decay of naturally 
radioactive elements. ... In Earth's continental crust, the decay of natural 
radioactive isotopes has had .... Thus, if the geothermal heat flow rising through 
an acre of granite terrain... [DOC] [TLE] Earth's internal heat budget - Wikipedia [PAR] The flow of heat from Earth's interior to the surface is estimated at 47 terawatts (
TW) and comes from two main sources in roughly equal amounts: the radiogenic 
heat produced by the radioactive decay of isotopes in the mantle and crust, and 
the primordial heat ... The radioactive decay of elements in the Earth's mantle and 
crust results in... [DOC] [TLE] Some unanswered questions [This Dynamic Earth, USGS] [PAR] May 5, 1999 ... Both the Earth's surface and its interior are in motion. ... Below a depth of about 
700 km, the descending slab begins to soften and flow, losing its form. ... in a 
circular manner somewhat like a pot of thick soup when heated to boiling. ... 
chemical elements -- most notably uranium, thorium, and potassium... [DOC] [TLE] Earth Structure, Materials, Systems, & Cycles - Tulane University [PAR] Aug 31, 2016 ... In the Earth's crust the most abundant elements are as follows: .... This type of 
energy usually is converted to heat. ... Some elements like Uranium, Thorium, 
and Potassium have ... Magmas rising from the underlying asthenosphere intrude 
and erupt .... Into Atmosphere by decay, respiration, & burning. [DOC] [TLE] Earth Differentiation - Indiana University Bloomington [PAR] Jan 17, 2001 ... 1) radioactive decay of U, Th, and 40K produced a buildup of heat in the Earth 
interior (probably the most important contributor). The figure at ... risen to the 
surface in molten form, giving rise to ... Uranium and Thorium are very heavy 
elements, and we should therefore expect them to be enriched in the core. [DOC] [TLE] Why is the earth's core so hot? And how do scientists measure its ... [PAR] This occurs through both "convective" transport of heat within the earth's ... 
bringing small bodies together to form the proto-earth, is large: on the order ... 
elements (primarily potassium, uranium and thorium) are is poorly known in the 
deep earth. ... are quite similar to those seen in of iron at high pressures and 
temperatures,... [DOC] [TLE] Where does Earth get its heat? - Martian Chronicles - AGU ... [PAR] Jan 24, 2013 ... Others assume that radioactive decay causes the heat, but with the advent of 
nuclear plants ... In particular, potassium, uranium, and thorium. [DOC] [TLE] The Engine that Drives Earth : Oceanus Magazine [PAR] Jan 30, 2004 ... The

Question: Heat rising from within the Earth is mostly from this type of decay of elements like uranium & thorium
Answer: radioactive decay