Plate tectonics and climate during the Cenozoic period – get along with it?

By Andy May

In this article, I looked at the agents used to compare CO₂ To 66 million years ago (MA) to today's temperature and comment on comparing the quality. Furthermore, we examined the Cenozoic plate tectonic events that affect global climate. Figure 1 compares the deep-sea D18O (Oxygen-18 isotope anomaly, temperature proxy) from Westerhold et al. with D13C (Carbon 13 isotope anomaly), both of which are from the same fossils, so they can be compared directly. One of many temperature/CO problems₂ Graphs are usually from different sources and locations, and they are not directly comparable due to dating errors and time resolutions. Although D13C is not a direct CO₂ It is estimated that it has something to do with CO₂ The deep sea is concentrated. Atmosphere and ocean₂ The concentration estimates were compared with D13C in Figure 2.

The large plate tectonic event is noted in Figure 1, the conversion from D18O to the deep sea temperature to the left. When the deep sea temperature was 12°C higher than today, the highest temperature in the Cenozoic was from the early Eocene (~56-48 mA). With the dramatic decline of Deep Sea Company₂. As mentioned earlier, D13C is not an estimated value for CO₂ concentration, but related to it. Agent Estimates for CO₂ From Rae et al. The D13C estimates of Westerhold in Figure 2 are compared.

The match in Figure 2 is not very good, and both datasets have problems, but the similarities in trends are obvious. CO estimates₂ Concentrations reported by Rae et al. is discontinuous and comes from a number of agents with many authors with many different techniques. It can be clearly seen from the dispersion that assumption₂ This compression time scale is not applicable to even distribution worldwide. Note that in both records, PETM (Paleocene-Eocene Maximum) Carbon isotope offset (CIE) events were significantly displayed in ~56 mA. The larger difference in ratios between carbon-13 and carbon-12 is a prominent global rock record phenomenon and is a reliable geological time marker between 55.6 and 55.4 MA. The possible reasons for CIE and PETM are discussed here. This geological event and the warmest period below are the most dramatic climate events in the Ku comprehensive.

An important event at the beginning of PETM is 56 to 55.6 MA, which is a North Atlantic volcanic province or “Naip” volcanic plant. This is a series of huge volcanic eruptions accompanied by the opening of the North Atlantic Ocean and the placement of 5 km of lava between Greenland and Northern Europe (Stokke et al., 2020). It almost turned the North Sea into a lake. However, regardless of the reasons for the best climate in Petm and early Eocene (Eeco, ~56-48 Ma) periods, they are very evident in the rock record and are easily identifiable in geological parts around the world.

After EECO, the deep sea temperature begins to drop for a long time. initial₂ but at the beginning of the Oligocene it began to decline, and the decline in the mid-Midocene became increasingly dramatic.

During PETM and subsequent warming periods, the mainland is configured as shown in Figure 3.

Note that all oceans are connected by sea channels at the northern and central latitudes and are marked with white lines. India is crossing the Indian Ocean and colliding with Asia. The Arctic may be isolated by land, and the Southern Ocean is blocked by land linking South America and Australia to Antarctica. This is the warmest planetary configuration, and EECO is classified as a “Hothouse” climate by Christopher Scots (Scotese, Song, Song, Mills & Meer, 2021) and Westerhold, among others. Hothouse climate is above 20°C global average temperature (land and ocean), and neither pole has ice all year round.

Arctic sea surface temperature (SST) may have reached 24°C during EECO. Today's estimates of the global average SST vary, but HADSST4 estimates the global average of about 20.5°C and NOAA estimates about 19.7°C, so EECO Arctic SST temperatures may be 4°C higher than today's global average.

The next major event was when India collided with Asia, which occurred between 46 and 44 MA, as shown in Figure 4. The collision started as early as 59 MA, but the ocean fossils in the Himalayan sediments did not disappear until 45 MA (Hu et al., 2016).

Consistent with this collision are some moderate cooling and the increase in CO₂. With the growth of Himalayas following collisions, they begin to cause planetary waves (more specifically gravitational waves of terrain), which may greatly affect weather in the Northern Hemisphere (Trenberth & Chen, 1988) and (Kuchar et al., et al., 2022). Planetary waves affect Arctic vortex, which is the main determinant of winter weather in the Northern Hemisphere.

The next big event is the opening of the Drake Passage, which connects the Southern Oceans across the Antarctic. The event is very gradual, but seems to be done by 34 mA, as shown in Figure 5. Just like most ocean passages open or closed, it is difficult to fix, with estimated opening hours ranging from 49 to 17 mA. Antarctic ice begins to grow about 44 mA, and by 34 MA, the ice sheet is finished. This coincides with a sharp drop in global temperatures and CO drops₂.

As shown in Figure 6, the next major event occurred around 31 ma, when the Mediterranean was cut off from the Indian Ocean. The timing of Mediterranean separation and Indian Ocean separation is often debated and may occur at 14 mA, we prefer an earlier closure, at some point between 31 and 24 mA. Sedimentology shows that the latest possible closing date is 24 mA.

Next, about 17 mA, the North Atlantic Ocean is fully open and connected to the Arctic. Panama may begin closing at this time, limiting the connection between the Atlantic Ocean and the Pacific Ocean, as well as the western part of Spain. The western Mediterranean may have been late for 6 MAs, but it is certainly severely restricted by 17 MAs. These events are consistent with a sharp drop in global temperature and deep-sea CO₂. These events hover in Figure 7. The opening of the North Atlantic Ocean is about 13 mA, and it is not complete until about 3 mA, the complete and permanent closure of Panama is not complete.

These very dramatic events coincide with a sharp drop in temperature and CO₂ The Miocene ended with the best climate. The closing of the Panama isthmus takes a long time, and when it finally closes, it was the subject of many debates (Coates & Stallard, 2013), but the closing is certainly done by 3 MA, as shown in Figure 8.

There are many reasons for long-term climate change, but one of the main factors is plate tectonics and continental drift. The world is colder when continents and oceans are oriented north-south as they are today, which limits western (regional) air flow and encourages north-south (merid) air flow. As shown in Figure 3, the opposite is true when the central to low-latency open ocean connection encourages western flow.

Another major impact on long-term climate change is the Milankovitch cycle (see also here). The impact of plate tectonics on climate change is long-term, with Milankovic cycles working over hundreds of thousands of years. Shorter periods of change are often associated with changes in the sun itself, and these work hours are shorter than thousands of years.

In the Westerhold study plotted in Figure 1, the authors noticed a strong correlation between the astronomy Milankovitch cycle of 21, 41, 41, 100, and 405 millennium (KYR) lengths and patterns in its global deep-sea D18O and D13C data. Since repeated Milankovitch astronomical cycles are more computed, more reliable and more accurate than any other dating technique, they use them to order and date the data plotted in Figure 1. Their description of this work is in Section 5 of its supplementary material (“Astrology”). For records over 20 mA, only longer eccentric periods can be used. The most prominent and most stable cycle is the 405 Kyr eccentric cycle.

Westerhold et al. It was concluded that its chronology accuracy for the Pleistocene and Eocene was ±100 kyr, ±50 kyrs of the Oligocene, and ±10 kyrs of the Miocene and Pleistocene. If true, this accuracy is significant, and given their technology, it seems reasonable.

Comparing known Cenozoic climate change with Scots’ plate tectonic reconstructions shows that over millions of years, major climate change coincides with large geological events. Therefore, it is easy and logical to conclude that geological events cause long-term changes. I found Westerhold and others very encouraging. The Milankovic astronomical cycles in its deep-sea fossil record can be clearly and clearly “see” so that they can be used for dating. One of the biggest problems with comparing CO₂ The temperature record is CO₂ Records are made using different samples and must be separated from the temperature agent sample date. This gives me greater confidence in the D13C data in Figures 1 and 2 compared to Rae et al. The data shown in Figure 2. Further highlighted gaps in Rae et al. company₂ The data gives you too much imagination.

Westerhold's Deep Sea D13C Agent is not a direct company₂ Agent, but can be paired directly with a D18O temperature proxy and is continuous. These characteristics make it superior to other CO₂ I think the agent.

I should point out that the exact timing of the major plate tectonic events discussed in this article is the subject of anger debate in geological communities (Hu et al., 2016; Torfstein & Steinberg, 2020, Coates & Stallard, Coates & Stallard, 2013). The exact date for the North Atlantic Ocean, which is closed or open to the Arctic when India collided with Asia, is not clear. They occur over millions of years, and different geological studies can reasonably provide different dates, depending on the data used. Therefore, the dates given in this study are based solely on my best judgment and open to debate.

Download the bibliography here.

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