Historia registrada nas rochas | Terra Viva #2

[Music] for [Music] no [Music] [Applause] [Music] [Music] main goal for a geologist uh you know just take the the name the the etimology of the word you know G geology is the study of the earth and so loia logos is the same word that from the Greek means intellect or understanding or um word and reason so so the dialectic component the ability to frame a hypothesis and to express that hypothesis and the intellectual component the ability to create a logical uh framework a logical organized logically your set of observations and data and G the Earth

um is really the context in which you are putting this effort you know within the context of understanding our plan so for a geologist the goal is to make sense to organize to find the common thread to find patterns to find sense to find meaning to find organization to find U design also in uh in what we observe in on planet Earth the earth is made up of rocks uh the core of the earth is made up of one kind of rocks and then there's the mantle and the crust so the entire earth is made

up of a variety of rocks but we think most of the rocks at the surface so a lot of the time geologists are looking just at the different kind of rocks at the surface of the Earth um um and there's different environments for the different rocks to form at the surface of the Earth so one kind is if you have liquid rocks that come up from the interior of the earth they come up to the surface and come out and so everybody knows about those at volcanoes you get lava that comes out so that's one

kind of rocks now if the liquid rock if the magma comes up but it doesn't come all the way to the surface like a volcano and stops underground maybe several kilometers underground then it cools slowly and you can get large crystals and those large crystals you can see in granates in granitic kind of rocks now those volcanic rocks and granitic rocks are called ous rocks another kind of rock is a metamorphic rock and that's where the rocks are hot but they don't get hot enough so they're liquid they're just hot enough so that they're plastic

and they can fold and different minerals can form and so metamorphic rocks are rocks that are formed under high pressures and temperatures one example of that is marble um another example that you might be familiar with is slate which is a rock that has been heated up just a little bit and some of the minerals have changed then the third kind of rock is a sediment Rock a sedimentary rock is probably the kind you're most familiar with and it forms at the surface usually by uh water by the action of water sometimes by wind but

most of the time by water and so if you have water carrying along sediments like sand and the sand is deposited like on a beach and then it gets covered up the sand can turn to Sandstone so that's a very typical sedimentary rock if you have very high energy environments then it can carry Pebbles or Boulders and then you'll get a conglomerate so it conglomerates another kind of sedimentary rock if the water is not moving very fast at all or if it's not moving then you can have the mud in the water will gradually settle

out to the bottom make mud at the bottom and then uh over time that mud can Harden into rock called shale so those are various kind of rocks that um are called clastic rocks that are due to water carrying particles along another kind of rock are chemical rocks where you have um material precipitated out of the water so if you have something like calcium and carbonate precipitated out of the water then you'll get limestones and a limestone is a very common sedimentary rock another kind of chemical sedimentary rock is um what are called evaporites if

you have all of the water evaporate away then whatever left um whatever minerals are left in the Rock uh get precipitated out for example ocean water has salt in it but if all of the water gets evaporated away you're left with the salt and you'd have a salt deposit and so there are various places where you have sedimentary formations that are salt um another one is gypsum that's another kind of chemical [Music] precipitate for [Music] [Music] [Music] comp for [Music] [Music] [Music] metamorph for foran [Music] h [Music] for [Music] for landas [Music] okay so one

thing I do when I'm mapping uh here in eastern Iceland I I use the structure of the lava flows to tell me about their preservation and this this is an interesting place because we see the very contact of the lava flow with the welded tough on top and this contact here as you see this lower part here is is actually the very upper part of a lava flow and you could see it by the vesicles the very upper part of the lava flows has you know vesicles in it and as you get to the very

top of it the vesicles get smaller so this just means that this lava flow uh is perfectly preserved the very top of it is preserved but the next thing that happens is that this tough is deposited on top of the lava flow now I don't have the exact time here but it could be actually that uh these two deposit both the lava flow and the tough um were reped relatively rapidly and in Rapid sequence because there's seemingly not much time here if there was much time um usually weathering uh each each the crust of the

lava flow it is very vulner the top of it is very vulnerable to weathering so it would degrade and form a soil section into the crust but we don't see that here and actually in in most of the lava flows that I've met the lava flows are perfectly preserved suggesting rapid deposition geologists have at least two ways of you know identifying time one is through radiogenic elements that have a half life and they get thousands of and millions of years by looking by by by dating rocks another way is to look at the Rocks themselves

and and and and to see what are the Rocks telling me and what do the processes that form these rocks uh what what do they tell me about time about this sequence of events and and so forth and I personally uh am very interested in this story that the rocks are telling me and and actually how they correlate with then these other clocks that we uh geologies use and and yeah certainly um in my view there is a problem there to be solved because there's not much correlation always between the story the rocks are telling

me and then between these you know radiogenic clocks [Music] [Music] as you study geology you're studying various processes and as you study the processes you need to have a picture of the sequence what happened first what happened next what are the causes what are the effects so you need to know the order of events if you want to study the relative time between rocks uh if the rocks are close to each other you can see how they're related to each other and probably figure out which came first and which came second however if the rocks

are a long ways apart you have some rocks in Europe and you have some rocks in South America how do you figure out what the relation is in time between those rocks and so geologists have developed uh a technique for determining ages for rocks that are a long ways apart and that's radiometric dating that looks at the atoms in the Rocks radioactive atoms uranium is radioactive it decays to lead pottassium is radioactive that decays to argon rubidium is radioactive that decays to strontium and so if you count the number of parent atoms like uranium and

you count the number of daughter atoms like lead you can figure out the ratio between them and figure out how long it's been decaying and so this is one of the most popular techniques that geologists use to find the ages the relative ages between different Rock units and what happened first what happened later what's the cause and what the what what is the effect for [Music] GR fore [Music] El [Music] [Music] [Music] uh [Music] for [Music] for for one of the most critical issues that we have to face as geologists is is the question of

time most geologists are are absolutely certain that the world is as we know it has been here for for billions of years and that life has been on the earth for hundreds of millions of years and that these processes have been going on through all that time when we read the story in the Bible we realize that that is inconsistent with this with what we read there that the Bible is giving a very different picture of life on the earth that it's been here for a few thousand years and not for millions of years and

that this is a consonant part of the whole story of of the Bible then we have to go back and re-evaluate things and when we do that we find out that we overlooked some very important features uh for example we find out that if sediments had accumulated slowly like geologist would want them to they would be accumulating a thousand times slower than they are today and today we don't see anything spectacular going on we just see normal processes but the rate of accumulation is about a thousand times faster than the rates we get if we

use radiometric dates for the accumulation of sediments so how do you explain that well that's one thing you see another thing you see is that the sediments themselves don't appear to have been subjected to time because if you lay down a layer of sediment in the ocean and it has internal structures that you can see and then you leave it there for a day or a week or a month or year and you come back and look you'll find out that animals have burrowed into that sediment and have destroyed all the internal structures so it

doesn't take very long before sediments would no longer talk to us they would no longer have the information that sedimentologists need to understand the sediments And yet when we look at the rocks and we see the layers of rock we can see inside and we can read this the story that they tell we don't see evidence for time what we see is that one layer is deposited and then before it can be disturbed another layers put on top and so on and very seldom do we find any extensive evidence for for a period of time

so this is consistent and explain explainable if we allow that there hasn't been very much time but if we allow that there are millions of years such as uh the data we get from radiometric dating then you can't understand why these sedimentary structures are still there why haven't the burrowing of animals and and other other forces change the internal structure of the layers so this is a big mystery that that our understanding of time offers a solution to that is not explainable in terms of long ages of time and there are other things like that

for example a layer that I study in in Utah it has some supposedly 10 to 30 million years missing between two layers and yet it's perfectly flat there's been no erosion before the layer was put on top and yet they're supposed to be 30 million years well 10 million years is enough time to erode all of North America away to sea level and if you had 10 million years and nothing's happening how do you explain that there is evidence uh that the the material underneath was still soft it was not Consolidated this is evidence because

the overlying material has pushed down into it and this could only happen if it was still mud it wouldn't happen if it had been turned to rock so we can see that there wasn't enough time to for the layer to become hard like rock it was still soft and muddy but if it was soft and muddy for 10 million years Why didn't it erode away and so we have an enigma but if we consider that the time wasn't millions of years but maybe was very quick then we can understand and explain that conventional geologists think

that there are millions of years passing as these layers are deposited one on top of the other uh those of us who take the Bible account seriously we don't see those millions of years being there we don't believe they were that there were there were millions of years we don't believe there was that much time there's still some time that passes it's been thousands of years since creation um and but how do we deal with this difference the thousands of of years compared with millions of years um the what ha one of the things that

happens is if you are a conventional geologist you have come to believe firmly that there were these millions of years you look at the rocks and you automatically interpret them that way as forming very slowly maybe there are catastrophes but lots of time passing in between um but but those of us who take the Bible seriously we see it differently and we will look for things and ask questions that the conventional gist doesn't ask um the Bible actually opens our minds and opens our eyes to see things that other people are not noticing to ask

questions that others are not asking when we do that we discover things that uh a person a conventional galst probably won't even notice we ask questions that they are not likely to ask cuz it wouldn't be mean anything in their point of view if you have a mind that is closed to certain possibilities that are not unreasonable but maybe are outside the purview of whatever discipline you're working in you will not think of certain ways of explaining the world around you one of the advantages I have as a Christian geologist who believes in the biblical

account of Origins is that I can look at things on a broader persp perspective I can consider not only the explanations of standard geologists but I can consider a whole perspective beyond that which involves catastrophic processes on on a global scale and when I do that and I look at the Rock record in those terms I can see explanations that other geologists wouldn't think of [Music] [Music] [Music]