Previous posts in the series:
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The Grand Canyon, Monument to an Ancient Earth: Can Noah’s Flood Explain the Grand Canyon?
By Gregg Davidson, Joel Duff, David Elliott, Tim Helble, Carol Hill, Stephen Moshier, Wayne Ranney, Ralph Stearley, Bryan Tapp, Roger Wiens, and Ken Wolgemuth.
Part 2 – “How Geology Works” is an impressive primer on basic geology especially as it relates to the Grand Canyon. The section is divided into:
- Chapter 5- Sedimentary Rock Types and How They Form
- Chapter 6- Sedimentary Structures: Clues from the Scene of the Crime
- Chapter 7- Using the Present to Understand the Past
- Chapter 8- Solving Puzzles: Relative Dating and the Geologic Column
- Chapter 9- So Just How Old is That Rock?
- Chapter 10- Missing Time: Gaps in the Rock Record
TECTONICS & STRUCTURE
- Chapter 11- Plate Tectonics: Our Restless Earth
- Chapter 12- Broken and Bent Rock: Fractures, Faults, and Folds
It is 75 pages of photographs, illustration, and laymen-friendly text that will give you a basic understanding of the natural processes that formed the Grand Canyon. Over and over again, flood geologists and young earth creationists assert the “One World-Two Views” theory that they are looking at the same evidence as “secular” scientists only with a different (Biblical) worldview. We “secularists” and “compromisers” are assuming an evolutionary viewpoint therefore we reason circularly to an evolutionary conclusion. But as the reader will see from this section; the only thing assumed is that the laws of physics and chemistry that we observe today have operated the same way in the past. In fact, if one doesn’t make that assumption, one cannot do science.
Chapter 5 begins with; “Sedimentary rocks are emphasized in the next three chapters, in part because they are the rocks that make up the bulk of the Grand Canyon and the Grand Staircase to the north, and also because much of what we know about Earth’s overall history is contained in sedimentary rocks.” Chapter 4 ended with a rhetorical question: “Can anyone know what actually happened in the unobserved past?” The answer to that question for a particular area my take years of study, but the basic tools in a geologist’s toolbox are actually fairly simple; start by observing how sediments form today.
Sediments that make up sedimentary rocks will reflect their source rock, their alteration during transport, the environment where they are deposited, and post-depositional transformation from pressure, heat, and water chemistry or cementation.
Common sediment particles are classified according to their size:
Mud is usually taken to mean water mixed with varying amounts of clay or silt. Mud turned into rock is mudstone, rock composed of sand is sandstone, rock composed of silt is siltstone, rock composed of clay is shale (you thought I was going to say claystone- we geologists are nothing if not prosaic), and rock composed of a mixture of gravel and pebbles with sand and mud is conglomerate.
Limestone is rock formed from accumulation of calcium carbonate shell fragments and limey mud. Lime sediment is accumulating today across the Grand Bahamas Bank, seaward of the Florida Keys and behind them in Florida Bay, along the coast of the Persian Gulf, and anywhere coral reefs are growing.
No limestone has ever been documented to form from floodwater- either in the laboratory, or from field observations- not even in floods as massive as formed the Channeled Scablands in Washington State (discussed in Chapter 16). Quite simply, limestone is one type of rock that takes a long time to be deposited- much longer than the time span of a flood. (Chapter 5, page 61)
The observable fact about flood deposits, especially large turbulent floods is that they lay sediment down in order of the flood’s decreasing energy. The first part of the flood, the highest energy part, doesn’t deposit at all, in fact, it erodes and scours. Then as the flood’s energy decreases the largest sediment particles are laid down, the cobbles, pebbles, and gravels. Then sand is laid down followed by silt, and finally clay. If your home has ever flooded you are all too familiar with the sticky, hard to clean muck that is left after a flood recedes. Now remember, according to the flood geologists all the sediments from the above the Supergroup, not just to the top of canyon rim, but all the way up the Grand Staircase to Bryce Canyon were laid down in Noah’s flood and then eroded all at once after the flood. So we start with the Tapeats Sandstone then the Bright Angel Shale then the Muav and Redwall Limestones. Well, maybe OK, at least we are decreasing energy. But then, wait, we get to the Supai Group and then it is sandstone again in the Esplanade Sandstone. Then alternating shales and siltstones, then the Coconino Sandstone, then the Toroweap and Kaibab limestones again and so on up the Grand Staircase with alternating limestone, sandstones, siltstones and shales. Does that seem like one flood to you? Or is the conventional geologic model of the advancing of seas inland (transgression) and then retreat of the sea level (regression) over time a more reasonable explanation.
To quote from the book (Chapter 5, page 65):
The sedimentary layers found in the Grand Canyon can be easily explained by a succession of rising and falling sea levels. No fantastic or undiscovered natural processes need be invoked to account for what is observed. The flood geology model, on the other hand, requires many fantastic or never-before-seen explanations, including sediments accumulating at phenomenally high rates, unreproducible chemical reactions occurring in deep ocean fissures, mysterious lack of mixing of clay and lime in the same layers, monumental stockpiles of pre-flood sediments awaiting redistribution, and walls of sediment hundreds of feet high moving as a unit across continents. It’s remarkable that such speculations are even necessary, given the total absence of any descriptions of global tsunamis, catastrophic continental upheavals, massive gravity flows, or violations of natural laws in the Genesis account of Noah’s Flood.
Chapter 6– “Sedimentary Structures: Clues from the Scene of the Crime” covers such features as mud cracks, ripple marks, raindrop prints, cross bedding, and various types of animal tracks.
Mudcracks (also known as desiccation cracks or mud cracks) are sedimentary structures formed as muddy sediment dries and contracts. It is impossible for mud cracks to form during a flood obviously. Flood geologists try to explain this by appealing to syneresis cracks which happens when fine grained sediment settles and “dewaters” as it is compressed, or are formed by the contraction of clay in response to changes in the salinity of a liquid surrounding a deposit. Desiccation mudcracks are usually continuous, polygonal, and have U- or V- shaped cross sections that would have been filled in with sediment from above. Syneresis cracks, however, are usually discontinuous, spindle or sinuous in shape, and have U- or V- shaped cross sections that have been filled in with sediment from above or below.
Raindrop prints are made when droplets of pounding rain impact wet mud, silt, or sand, thus creating small depression imprints of those drops in the sediment. This can only happen when moist sediment is exposed to the air, because if the sediment is under water it cannot be impacted by raindrops. Raindrop prints have been found in the Coconino Sandstone at many locations.
Cross-beds are the groups of inclined layers, and the sloping layers are known as cross strata. Cross bedding forms on a sloping surface such as ripple marks and dunes, and allows us to interpret that the depositional environment was water or wind. Speaking of the Coconino Sandstone, the book points out that the maximum angle for loose dry sand is 30-34 degrees. Saturated sand in underwater dunes or ripple marks cannot maintain slopes as steep as dry sand in desert dunes. Coconino cross beds have angles typical of desert dunes with maximum angles of 29-30 degrees. Go back and look at the figure showing the Grand Canyon strata- where is the Coconino? So was there Sahara-level desert conditions in the middle of a world-wide flood? Or does the Coconino Sandstone represent a time when a desert environment was present in this area?
Chapter 7– “Using the Present to Understand the Past” begins with correcting the misrepresentation of uniformitarianism that YECs like to promote. Flood geologists commonly demonize it by making synonymous with materialism or evolutionism. But modern geologists have no problem recognizing that there were many places and times where catastrophic events have shaped the Earth’s various layers. And flood geologists who like to take the example of the 1980 eruption of Mt. St. Helens as a scenario under which the Grand Canyon formed are unwittingly performing an uniformitarian exercise. The eruption delivered dozens of feet of volcanic ash to the valleys below the mountain in the span of a few hours. That ash was subsequently eroded and impressive gorges were carved into the soft ash sediment.
The deposits contain layers and bedding which flood geologists like to say looks like rocks and cliff faces in the Grand Canyon. They totally miss the irony of comparing modern deposits (Mt. St. Helens) to ancient deposits (the Grand Canyon) is a fully uniformitarian exercise.
The book then goes on to describe, that if the present is the key to the past, we should be able to identify landscapes today that are comparable to Grand Canyon landscapes of the past. The book then lists and discusses 5 such landscapes:
- Bare Naked Rock (Crystalline Basement Rock Exposed by Erosion)- the Vishnu Schist
- Muck and Mud (Clay Deposition in a Shallow Near-Shore Sea)- the Bright Angel Shale
- Vacation Destination (Warm Seas and Carbonate Deposition)- the Muav Limestone
- Subterranean Labyrinth (Cave and Sinkhole Formation)- the Redwall Formation
- Hot and Dry (Desert Sands)- the Coconino Sandstone
The major point of discussing these examples is that the Grand Canyon deposits WERE JUST THAT — LANDSCAPES that existed in the ancient past. Each deposit represents an environment that existed at that time and place and we can know that because in the present environments around the world we observe sediments representing those environments being deposited now.
In my Science and the Bible series I made a big deal about paleokarst in the Redwall Limestone because the church class I was teaching lived and worked in middle of the famous southern Indiana karst terrain. They were intimately familiar with what a karst landscape looked like. They understood that a karst landscape, with sinkholes, springs, and caves, could not form in soft sediment in the middle of a flood.