本文選題：郯廬帶 + 晚第四紀(jì)�。� 參考：《大地測(cè)量與地球動(dòng)力學(xué)》2017年12期

【摘要】：探槽揭示,郯廬斷裂帶安徽泗縣徐井一帶第四紀(jì)以來(lái)的新活動(dòng)表現(xiàn)為逆斷型崩積楔、張裂楔、碎裂流和地震斷層。根據(jù)現(xiàn)場(chǎng)分析初步認(rèn)為,中更新統(tǒng)沉積后,探槽所在部位先遭受擠壓,晚白堊世磚紅色砂巖自西向東上沖垮塌到中更新世沉積之上,形成逆斷型崩積楔-1;接著發(fā)生張性斷裂活動(dòng),形成開口向上的張裂楔;隨后,所在部位又遭受擠壓,沿張裂楔的東邊界斷面擠壓逆沖活動(dòng)產(chǎn)生碎屑物質(zhì)上拋流動(dòng),形成逆斷型崩積楔-2;其上逐步形成更新沉積,當(dāng)黑土層堆積以后,再次遭受擠壓,使得斷面上下黑土層堆積厚度顯現(xiàn)差異。這表明中更新統(tǒng)沉積以后,斷裂曾先后發(fā)生擠壓-引張-擠壓-擠壓共4次活動(dòng),最新活動(dòng)在全新世早期。根據(jù)逆斷型崩積楔、張裂楔和地震斷層等的成因,這幾次活動(dòng)應(yīng)屬高速粘滑活動(dòng),對(duì)應(yīng)幾次強(qiáng)烈的史前地震活動(dòng)事件。上述認(rèn)識(shí)部分得到原態(tài)微觀觀測(cè)分析結(jié)果的證實(shí)。
[Abstract]:The trench reveals that the new activities since Quaternary in the area of Xujing, Sixian, Anhui Province, the Tanlu fault zone are characterized by reverse fault-type avalanche wedge, extensional wedge, cataclastic flow and seismic fault. Based on the field analysis, it is concluded that after the Middle Pleistocene deposits, the location of the grooves was first squeezed, and the late Cretaceous brick red sandstone collapsed from west to east to the middle Pleistocene deposits. Forming an inverse faulted accretion wedge-1, followed by tensional fracture activity, forming an upward opening fracture wedge, and then the location is squeezed again, and the thrusting activity along the eastern boundary of the tensional wedge results in the upcast flow of debris material, which is caused by the thrusting activity along the eastern boundary of the detritus wedge. The formation of an inverse fault-type caving wedge -2, on which the renewal deposits are gradually formed, and when the black soil layer is accumulated, it is again squeezed, which makes the thickness of the upper and lower black soil layers appear to be different from that of the upper and lower sections. This indicates that the faults had four compression-extension-compression events after the Middle Pleistocene deposition, the latest activity occurred in the early Holocene. According to the origin of inverse fault type accretion wedge, tension wedge and seismic fault, these events should belong to high speed visco-slip activity, corresponding to several strong events of prehistoric seismicity. The above understanding is confirmed by the results of microscopic observation in the original state.
【作者單位】： 安徽省地震局;安徽蒙城地球物理國(guó)家野外科學(xué)觀測(cè)研究站;
【基金】：安徽省公益性地質(zhì)項(xiàng)目(2015-g-25)~~
【分類號(hào)】：P315.2
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本文編號(hào)：2015803